1 /*
   2  * Copyright (c) 1994, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package java.lang;
  26 
  27 import java.io.BufferedInputStream;
  28 import java.io.BufferedOutputStream;
  29 import java.io.Console;
  30 import java.io.FileDescriptor;
  31 import java.io.FileInputStream;
  32 import java.io.FileOutputStream;
  33 import java.io.IOException;
  34 import java.io.InputStream;
  35 import java.io.OutputStream;
  36 import java.io.PrintStream;
  37 import java.lang.annotation.Annotation;
  38 import java.lang.invoke.MethodHandle;
  39 import java.lang.invoke.MethodType;
  40 import java.lang.invoke.StringConcatFactory;
  41 import java.lang.module.ModuleDescriptor;
  42 import java.lang.reflect.Constructor;
  43 import java.lang.reflect.Executable;
  44 import java.lang.reflect.Method;
  45 import java.lang.reflect.Modifier;
  46 import java.net.URI;
  47 import java.net.URL;
  48 import java.nio.channels.Channel;
  49 import java.nio.channels.spi.SelectorProvider;
  50 import java.nio.charset.CharacterCodingException;
  51 import java.nio.charset.Charset;
  52 import java.security.AccessControlContext;
  53 import java.security.AccessController;
  54 import java.security.CodeSource;
  55 import java.security.PrivilegedAction;
  56 import java.security.ProtectionDomain;
  57 import java.util.Collections;
  58 import java.util.List;
  59 import java.util.Map;
  60 import java.util.Objects;
  61 import java.util.Properties;
  62 import java.util.PropertyPermission;
  63 import java.util.ResourceBundle;
  64 import java.util.Set;
  65 import java.util.WeakHashMap;
  66 import java.util.concurrent.Callable;
  67 import java.util.function.Supplier;
  68 import java.util.concurrent.ConcurrentHashMap;
  69 import java.util.stream.Stream;
  70 
  71 import jdk.internal.misc.CarrierThreadLocal;
  72 import jdk.internal.misc.Unsafe;
  73 import jdk.internal.util.StaticProperty;
  74 import jdk.internal.module.ModuleBootstrap;
  75 import jdk.internal.module.ServicesCatalog;
  76 import jdk.internal.reflect.CallerSensitive;
  77 import jdk.internal.reflect.Reflection;
  78 import jdk.internal.access.JavaLangAccess;
  79 import jdk.internal.access.SharedSecrets;
  80 import jdk.internal.misc.VM;
  81 import jdk.internal.logger.LoggerFinderLoader;
  82 import jdk.internal.logger.LazyLoggers;
  83 import jdk.internal.logger.LocalizedLoggerWrapper;
  84 import jdk.internal.util.SystemProps;
  85 import jdk.internal.vm.Continuation;
  86 import jdk.internal.vm.ContinuationScope;
  87 import jdk.internal.vm.StackableScope;
  88 import jdk.internal.vm.ThreadContainer;
  89 import jdk.internal.vm.annotation.ForceInline;
  90 import jdk.internal.vm.annotation.IntrinsicCandidate;
  91 import jdk.internal.vm.annotation.Stable;
  92 import jdk.internal.vm.annotation.ChangesCurrentThread;
  93 import sun.nio.fs.DefaultFileSystemProvider;
  94 import sun.reflect.annotation.AnnotationType;
  95 import sun.nio.ch.Interruptible;
  96 import sun.nio.cs.UTF_8;
  97 import sun.security.util.SecurityConstants;
  98 
  99 /**
 100  * The {@code System} class contains several useful class fields
 101  * and methods. It cannot be instantiated.
 102  *
 103  * Among the facilities provided by the {@code System} class
 104  * are standard input, standard output, and error output streams;
 105  * access to externally defined properties and environment
 106  * variables; a means of loading files and libraries; and a utility
 107  * method for quickly copying a portion of an array.
 108  *
 109  * @since   1.0
 110  */
 111 public final class System {
 112     /* Register the natives via the static initializer.
 113      *
 114      * The VM will invoke the initPhase1 method to complete the initialization
 115      * of this class separate from <clinit>.
 116      */
 117     private static native void registerNatives();
 118     static {
 119         registerNatives();
 120     }
 121 
 122     /** Don't let anyone instantiate this class */
 123     private System() {
 124     }
 125 
 126     /**
 127      * The "standard" input stream. This stream is already
 128      * open and ready to supply input data. Typically this stream
 129      * corresponds to keyboard input or another input source specified by
 130      * the host environment or user. In case this stream is wrapped
 131      * in a {@link java.io.InputStreamReader}, {@link Console#charset()}
 132      * should be used for the charset, or consider using
 133      * {@link Console#reader()}.
 134      *
 135      * @see Console#charset()
 136      * @see Console#reader()
 137      */
 138     public static final InputStream in = null;
 139 
 140     /**
 141      * The "standard" output stream. This stream is already
 142      * open and ready to accept output data. Typically this stream
 143      * corresponds to display output or another output destination
 144      * specified by the host environment or user. The encoding used
 145      * in the conversion from characters to bytes is equivalent to
 146      * {@link Console#charset()} if the {@code Console} exists,
 147      * <a href="#stdout.encoding">stdout.encoding</a> otherwise.
 148      * <p>
 149      * For simple stand-alone Java applications, a typical way to write
 150      * a line of output data is:
 151      * <blockquote><pre>
 152      *     System.out.println(data)
 153      * </pre></blockquote>
 154      * <p>
 155      * See the {@code println} methods in class {@code PrintStream}.
 156      *
 157      * @see     java.io.PrintStream#println()
 158      * @see     java.io.PrintStream#println(boolean)
 159      * @see     java.io.PrintStream#println(char)
 160      * @see     java.io.PrintStream#println(char[])
 161      * @see     java.io.PrintStream#println(double)
 162      * @see     java.io.PrintStream#println(float)
 163      * @see     java.io.PrintStream#println(int)
 164      * @see     java.io.PrintStream#println(long)
 165      * @see     java.io.PrintStream#println(java.lang.Object)
 166      * @see     java.io.PrintStream#println(java.lang.String)
 167      * @see     Console#charset()
 168      * @see     <a href="#stdout.encoding">stdout.encoding</a>
 169      */
 170     public static final PrintStream out = null;
 171 
 172     /**
 173      * The "standard" error output stream. This stream is already
 174      * open and ready to accept output data.
 175      * <p>
 176      * Typically this stream corresponds to display output or another
 177      * output destination specified by the host environment or user. By
 178      * convention, this output stream is used to display error messages
 179      * or other information that should come to the immediate attention
 180      * of a user even if the principal output stream, the value of the
 181      * variable {@code out}, has been redirected to a file or other
 182      * destination that is typically not continuously monitored.
 183      * The encoding used in the conversion from characters to bytes is
 184      * equivalent to {@link Console#charset()} if the {@code Console}
 185      * exists, <a href="#stderr.encoding">stderr.encoding</a> otherwise.
 186      *
 187      * @see     Console#charset()
 188      * @see     <a href="#stderr.encoding">stderr.encoding</a>
 189      */
 190     public static final PrintStream err = null;
 191 
 192     // Holder for the initial value of `in`, set within `initPhase1()`.
 193     private static InputStream initialIn;
 194 
 195     // indicates if a security manager is possible
 196     private static final int NEVER = 1;
 197     private static final int MAYBE = 2;
 198     private static @Stable int allowSecurityManager;
 199 
 200     // current security manager
 201     @SuppressWarnings("removal")
 202     private static volatile SecurityManager security;   // read by VM
 203 
 204     // `sun.jnu.encoding` if it is not supported. Otherwise null.
 205     // It is initialized in `initPhase1()` before any charset providers
 206     // are initialized.
 207     private static String notSupportedJnuEncoding;
 208 
 209     // return true if a security manager is allowed
 210     private static boolean allowSecurityManager() {
 211         return (allowSecurityManager != NEVER);
 212     }
 213 
 214     /**
 215      * Reassigns the "standard" input stream.
 216      *
 217      * First, if there is a security manager, its {@code checkPermission}
 218      * method is called with a {@code RuntimePermission("setIO")} permission
 219      *  to see if it's ok to reassign the "standard" input stream.
 220      *
 221      * @param in the new standard input stream.
 222      *
 223      * @throws SecurityException
 224      *        if a security manager exists and its
 225      *        {@code checkPermission} method doesn't allow
 226      *        reassigning of the standard input stream.
 227      *
 228      * @see SecurityManager#checkPermission
 229      * @see java.lang.RuntimePermission
 230      *
 231      * @since   1.1
 232      */
 233     public static void setIn(InputStream in) {
 234         checkIO();
 235         setIn0(in);
 236     }
 237 
 238     /**
 239      * Reassigns the "standard" output stream.
 240      *
 241      * First, if there is a security manager, its {@code checkPermission}
 242      * method is called with a {@code RuntimePermission("setIO")} permission
 243      *  to see if it's ok to reassign the "standard" output stream.
 244      *
 245      * @param out the new standard output stream
 246      *
 247      * @throws SecurityException
 248      *        if a security manager exists and its
 249      *        {@code checkPermission} method doesn't allow
 250      *        reassigning of the standard output stream.
 251      *
 252      * @see SecurityManager#checkPermission
 253      * @see java.lang.RuntimePermission
 254      *
 255      * @since   1.1
 256      */
 257     public static void setOut(PrintStream out) {
 258         checkIO();
 259         setOut0(out);
 260     }
 261 
 262     /**
 263      * Reassigns the "standard" error output stream.
 264      *
 265      * First, if there is a security manager, its {@code checkPermission}
 266      * method is called with a {@code RuntimePermission("setIO")} permission
 267      *  to see if it's ok to reassign the "standard" error output stream.
 268      *
 269      * @param err the new standard error output stream.
 270      *
 271      * @throws SecurityException
 272      *        if a security manager exists and its
 273      *        {@code checkPermission} method doesn't allow
 274      *        reassigning of the standard error output stream.
 275      *
 276      * @see SecurityManager#checkPermission
 277      * @see java.lang.RuntimePermission
 278      *
 279      * @since   1.1
 280      */
 281     public static void setErr(PrintStream err) {
 282         checkIO();
 283         setErr0(err);
 284     }
 285 
 286     private static volatile Console cons;
 287 
 288     /**
 289      * Returns the unique {@link java.io.Console Console} object associated
 290      * with the current Java virtual machine, if any.
 291      *
 292      * @return  The system console, if any, otherwise {@code null}.
 293      *
 294      * @since   1.6
 295      */
 296      public static Console console() {
 297          Console c;
 298          if ((c = cons) == null) {
 299              synchronized (System.class) {
 300                  if ((c = cons) == null) {
 301                      cons = c = SharedSecrets.getJavaIOAccess().console();
 302                  }
 303              }
 304          }
 305          return c;
 306      }
 307 
 308     /**
 309      * Returns the channel inherited from the entity that created this
 310      * Java virtual machine.
 311      *
 312      * This method returns the channel obtained by invoking the
 313      * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
 314      * inheritedChannel} method of the system-wide default
 315      * {@link java.nio.channels.spi.SelectorProvider} object.
 316      *
 317      * <p> In addition to the network-oriented channels described in
 318      * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
 319      * inheritedChannel}, this method may return other kinds of
 320      * channels in the future.
 321      *
 322      * @return  The inherited channel, if any, otherwise {@code null}.
 323      *
 324      * @throws  IOException
 325      *          If an I/O error occurs
 326      *
 327      * @throws  SecurityException
 328      *          If a security manager is present and it does not
 329      *          permit access to the channel.
 330      *
 331      * @since 1.5
 332      */
 333     public static Channel inheritedChannel() throws IOException {
 334         return SelectorProvider.provider().inheritedChannel();
 335     }
 336 
 337     private static void checkIO() {
 338         @SuppressWarnings("removal")
 339         SecurityManager sm = getSecurityManager();
 340         if (sm != null) {
 341             sm.checkPermission(new RuntimePermission("setIO"));
 342         }
 343     }
 344 
 345     private static native void setIn0(InputStream in);
 346     private static native void setOut0(PrintStream out);
 347     private static native void setErr0(PrintStream err);
 348 
 349     private static class CallersHolder {
 350         // Remember callers of setSecurityManager() here so that warning
 351         // is only printed once for each different caller
 352         static final Map<Class<?>, Boolean> callers
 353             = Collections.synchronizedMap(new WeakHashMap<>());
 354     }
 355 
 356     // Remember initial System.err. setSecurityManager() warning goes here
 357     private static volatile @Stable PrintStream initialErrStream;
 358 
 359     private static URL codeSource(Class<?> clazz) {
 360         PrivilegedAction<ProtectionDomain> pa = clazz::getProtectionDomain;
 361         @SuppressWarnings("removal")
 362         CodeSource cs = AccessController.doPrivileged(pa).getCodeSource();
 363         return (cs != null) ? cs.getLocation() : null;
 364     }
 365 
 366     /**
 367      * Sets the system-wide security manager.
 368      *
 369      * If there is a security manager already installed, this method first
 370      * calls the security manager's {@code checkPermission} method
 371      * with a {@code RuntimePermission("setSecurityManager")}
 372      * permission to ensure it's ok to replace the existing
 373      * security manager.
 374      * This may result in throwing a {@code SecurityException}.
 375      *
 376      * <p> Otherwise, the argument is established as the current
 377      * security manager. If the argument is {@code null} and no
 378      * security manager has been established, then no action is taken and
 379      * the method simply returns.
 380      *
 381      * @implNote In the JDK implementation, if the Java virtual machine is
 382      * started with the system property {@code java.security.manager} not set or set to
 383      * the special token "{@code disallow}" then the {@code setSecurityManager}
 384      * method cannot be used to set a security manager. See the following
 385      * <a href="SecurityManager.html#set-security-manager">section of the
 386      * {@code SecurityManager} class specification</a> for more details.
 387      *
 388      * @param  sm the security manager or {@code null}
 389      * @throws SecurityException
 390      *         if the security manager has already been set and its {@code
 391      *         checkPermission} method doesn't allow it to be replaced
 392      * @throws UnsupportedOperationException
 393      *         if {@code sm} is non-null and a security manager is not allowed
 394      *         to be set dynamically
 395      * @see #getSecurityManager
 396      * @see SecurityManager#checkPermission
 397      * @see java.lang.RuntimePermission
 398      * @deprecated This method is only useful in conjunction with
 399      *       {@linkplain SecurityManager the Security Manager}, which is
 400      *       deprecated and subject to removal in a future release.
 401      *       Consequently, this method is also deprecated and subject to
 402      *       removal. There is no replacement for the Security Manager or this
 403      *       method.
 404      */
 405     @Deprecated(since="17", forRemoval=true)
 406     @CallerSensitive
 407     public static void setSecurityManager(@SuppressWarnings("removal") SecurityManager sm) {
 408         if (allowSecurityManager()) {
 409             var callerClass = Reflection.getCallerClass();
 410             if (CallersHolder.callers.putIfAbsent(callerClass, true) == null) {
 411                 URL url = codeSource(callerClass);
 412                 final String source;
 413                 if (url == null) {
 414                     source = callerClass.getName();
 415                 } else {
 416                     source = callerClass.getName() + " (" + url + ")";
 417                 }
 418                 initialErrStream.printf("""
 419                         WARNING: A terminally deprecated method in java.lang.System has been called
 420                         WARNING: System::setSecurityManager has been called by %s
 421                         WARNING: Please consider reporting this to the maintainers of %s
 422                         WARNING: System::setSecurityManager will be removed in a future release
 423                         """, source, callerClass.getName());
 424             }
 425             implSetSecurityManager(sm);
 426         } else {
 427             // security manager not allowed
 428             if (sm != null) {
 429                 throw new UnsupportedOperationException(
 430                     "The Security Manager is deprecated and will be removed in a future release");
 431             }
 432         }
 433     }
 434 
 435     private static void implSetSecurityManager(@SuppressWarnings("removal") SecurityManager sm) {
 436         if (security == null) {
 437             // ensure image reader is initialized
 438             Object.class.getResource("java/lang/ANY");
 439             // ensure the default file system is initialized
 440             DefaultFileSystemProvider.theFileSystem();
 441         }
 442         if (sm != null) {
 443             try {
 444                 // pre-populates the SecurityManager.packageAccess cache
 445                 // to avoid recursive permission checking issues with custom
 446                 // SecurityManager implementations
 447                 sm.checkPackageAccess("java.lang");
 448             } catch (Exception e) {
 449                 // no-op
 450             }
 451         }
 452         setSecurityManager0(sm);
 453     }
 454 
 455     @SuppressWarnings("removal")
 456     private static synchronized
 457     void setSecurityManager0(final SecurityManager s) {
 458         SecurityManager sm = getSecurityManager();
 459         if (sm != null) {
 460             // ask the currently installed security manager if we
 461             // can replace it.
 462             sm.checkPermission(new RuntimePermission("setSecurityManager"));
 463         }
 464 
 465         if ((s != null) && (s.getClass().getClassLoader() != null)) {
 466             // New security manager class is not on bootstrap classpath.
 467             // Force policy to get initialized before we install the new
 468             // security manager, in order to prevent infinite loops when
 469             // trying to initialize the policy (which usually involves
 470             // accessing some security and/or system properties, which in turn
 471             // calls the installed security manager's checkPermission method
 472             // which will loop infinitely if there is a non-system class
 473             // (in this case: the new security manager class) on the stack).
 474             AccessController.doPrivileged(new PrivilegedAction<>() {
 475                 public Object run() {
 476                     s.getClass().getProtectionDomain().implies
 477                         (SecurityConstants.ALL_PERMISSION);
 478                     return null;
 479                 }
 480             });
 481         }
 482 
 483         security = s;
 484     }
 485 
 486     /**
 487      * Gets the system-wide security manager.
 488      *
 489      * @return  if a security manager has already been established for the
 490      *          current application, then that security manager is returned;
 491      *          otherwise, {@code null} is returned.
 492      * @see     #setSecurityManager
 493      * @deprecated This method is only useful in conjunction with
 494      *       {@linkplain SecurityManager the Security Manager}, which is
 495      *       deprecated and subject to removal in a future release.
 496      *       Consequently, this method is also deprecated and subject to
 497      *       removal. There is no replacement for the Security Manager or this
 498      *       method.
 499      */
 500     @SuppressWarnings("removal")
 501     @Deprecated(since="17", forRemoval=true)
 502     public static SecurityManager getSecurityManager() {
 503         if (allowSecurityManager()) {
 504             return security;
 505         } else {
 506             return null;
 507         }
 508     }
 509 
 510     /**
 511      * Returns the current time in milliseconds.  Note that
 512      * while the unit of time of the return value is a millisecond,
 513      * the granularity of the value depends on the underlying
 514      * operating system and may be larger.  For example, many
 515      * operating systems measure time in units of tens of
 516      * milliseconds.
 517      *
 518      * <p> See the description of the class {@code Date} for
 519      * a discussion of slight discrepancies that may arise between
 520      * "computer time" and coordinated universal time (UTC).
 521      *
 522      * @return  the difference, measured in milliseconds, between
 523      *          the current time and midnight, January 1, 1970 UTC.
 524      * @see     java.util.Date
 525      */
 526     @IntrinsicCandidate
 527     public static native long currentTimeMillis();
 528 
 529     /**
 530      * Returns the current value of the running Java Virtual Machine's
 531      * high-resolution time source, in nanoseconds.
 532      *
 533      * This method can only be used to measure elapsed time and is
 534      * not related to any other notion of system or wall-clock time.
 535      * The value returned represents nanoseconds since some fixed but
 536      * arbitrary <i>origin</i> time (perhaps in the future, so values
 537      * may be negative).  The same origin is used by all invocations of
 538      * this method in an instance of a Java virtual machine; other
 539      * virtual machine instances are likely to use a different origin.
 540      *
 541      * <p>This method provides nanosecond precision, but not necessarily
 542      * nanosecond resolution (that is, how frequently the value changes)
 543      * - no guarantees are made except that the resolution is at least as
 544      * good as that of {@link #currentTimeMillis()}.
 545      *
 546      * <p>Differences in successive calls that span greater than
 547      * approximately 292 years (2<sup>63</sup> nanoseconds) will not
 548      * correctly compute elapsed time due to numerical overflow.
 549      *
 550      * <p>The values returned by this method become meaningful only when
 551      * the difference between two such values, obtained within the same
 552      * instance of a Java virtual machine, is computed.
 553      *
 554      * <p>For example, to measure how long some code takes to execute:
 555      * <pre> {@code
 556      * long startTime = System.nanoTime();
 557      * // ... the code being measured ...
 558      * long elapsedNanos = System.nanoTime() - startTime;}</pre>
 559      *
 560      * <p>To compare elapsed time against a timeout, use <pre> {@code
 561      * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
 562      * instead of <pre> {@code
 563      * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
 564      * because of the possibility of numerical overflow.
 565      *
 566      * @return the current value of the running Java Virtual Machine's
 567      *         high-resolution time source, in nanoseconds
 568      * @since 1.5
 569      */
 570     @IntrinsicCandidate
 571     public static native long nanoTime();
 572 
 573     /**
 574      * Copies an array from the specified source array, beginning at the
 575      * specified position, to the specified position of the destination array.
 576      * A subsequence of array components are copied from the source
 577      * array referenced by {@code src} to the destination array
 578      * referenced by {@code dest}. The number of components copied is
 579      * equal to the {@code length} argument. The components at
 580      * positions {@code srcPos} through
 581      * {@code srcPos+length-1} in the source array are copied into
 582      * positions {@code destPos} through
 583      * {@code destPos+length-1}, respectively, of the destination
 584      * array.
 585      * <p>
 586      * If the {@code src} and {@code dest} arguments refer to the
 587      * same array object, then the copying is performed as if the
 588      * components at positions {@code srcPos} through
 589      * {@code srcPos+length-1} were first copied to a temporary
 590      * array with {@code length} components and then the contents of
 591      * the temporary array were copied into positions
 592      * {@code destPos} through {@code destPos+length-1} of the
 593      * destination array.
 594      * <p>
 595      * If {@code dest} is {@code null}, then a
 596      * {@code NullPointerException} is thrown.
 597      * <p>
 598      * If {@code src} is {@code null}, then a
 599      * {@code NullPointerException} is thrown and the destination
 600      * array is not modified.
 601      * <p>
 602      * Otherwise, if any of the following is true, an
 603      * {@code ArrayStoreException} is thrown and the destination is
 604      * not modified:
 605      * <ul>
 606      * <li>The {@code src} argument refers to an object that is not an
 607      *     array.
 608      * <li>The {@code dest} argument refers to an object that is not an
 609      *     array.
 610      * <li>The {@code src} argument and {@code dest} argument refer
 611      *     to arrays whose component types are different primitive types.
 612      * <li>The {@code src} argument refers to an array with a primitive
 613      *    component type and the {@code dest} argument refers to an array
 614      *     with a reference component type.
 615      * <li>The {@code src} argument refers to an array with a reference
 616      *    component type and the {@code dest} argument refers to an array
 617      *     with a primitive component type.
 618      * </ul>
 619      * <p>
 620      * Otherwise, if any of the following is true, an
 621      * {@code IndexOutOfBoundsException} is
 622      * thrown and the destination is not modified:
 623      * <ul>
 624      * <li>The {@code srcPos} argument is negative.
 625      * <li>The {@code destPos} argument is negative.
 626      * <li>The {@code length} argument is negative.
 627      * <li>{@code srcPos+length} is greater than
 628      *     {@code src.length}, the length of the source array.
 629      * <li>{@code destPos+length} is greater than
 630      *     {@code dest.length}, the length of the destination array.
 631      * </ul>
 632      * <p>
 633      * Otherwise, if any actual component of the source array from
 634      * position {@code srcPos} through
 635      * {@code srcPos+length-1} cannot be converted to the component
 636      * type of the destination array by assignment conversion, an
 637      * {@code ArrayStoreException} is thrown. In this case, let
 638      * <b><i>k</i></b> be the smallest nonnegative integer less than
 639      * length such that {@code src[srcPos+}<i>k</i>{@code ]}
 640      * cannot be converted to the component type of the destination
 641      * array; when the exception is thrown, source array components from
 642      * positions {@code srcPos} through
 643      * {@code srcPos+}<i>k</i>{@code -1}
 644      * will already have been copied to destination array positions
 645      * {@code destPos} through
 646      * {@code destPos+}<i>k</I>{@code -1} and no other
 647      * positions of the destination array will have been modified.
 648      * (Because of the restrictions already itemized, this
 649      * paragraph effectively applies only to the situation where both
 650      * arrays have component types that are reference types.)
 651      *
 652      * @param      src      the source array.
 653      * @param      srcPos   starting position in the source array.
 654      * @param      dest     the destination array.
 655      * @param      destPos  starting position in the destination data.
 656      * @param      length   the number of array elements to be copied.
 657      * @throws     IndexOutOfBoundsException  if copying would cause
 658      *             access of data outside array bounds.
 659      * @throws     ArrayStoreException  if an element in the {@code src}
 660      *             array could not be stored into the {@code dest} array
 661      *             because of a type mismatch.
 662      * @throws     NullPointerException if either {@code src} or
 663      *             {@code dest} is {@code null}.
 664      */
 665     @IntrinsicCandidate
 666     public static native void arraycopy(Object src,  int  srcPos,
 667                                         Object dest, int destPos,
 668                                         int length);
 669 
 670     /**
 671      * Returns the same hash code for the given object as
 672      * would be returned by the default method hashCode(),
 673      * whether or not the given object's class overrides
 674      * hashCode().
 675      * The hash code for the null reference is zero.
 676      *
 677      * @param x object for which the hashCode is to be calculated
 678      * @return  the hashCode
 679      * @since   1.1
 680      * @see Object#hashCode
 681      * @see java.util.Objects#hashCode(Object)
 682      */
 683     @IntrinsicCandidate
 684     public static native int identityHashCode(Object x);
 685 
 686     /**
 687      * System properties.
 688      *
 689      * See {@linkplain #getProperties getProperties} for details.
 690      */
 691     private static Properties props;
 692 
 693     /**
 694      * Determines the current system properties.
 695      *
 696      * First, if there is a security manager, its
 697      * {@code checkPropertiesAccess} method is called with no
 698      * arguments. This may result in a security exception.
 699      * <p>
 700      * The current set of system properties for use by the
 701      * {@link #getProperty(String)} method is returned as a
 702      * {@code Properties} object. If there is no current set of
 703      * system properties, a set of system properties is first created and
 704      * initialized. This set of system properties includes a value
 705      * for each of the following keys unless the description of the associated
 706      * value indicates that the value is optional.
 707      * <table class="striped" style="text-align:left">
 708      * <caption style="display:none">Shows property keys and associated values</caption>
 709      * <thead>
 710      * <tr><th scope="col">Key</th>
 711      *     <th scope="col">Description of Associated Value</th></tr>
 712      * </thead>
 713      * <tbody>
 714      * <tr><th scope="row">{@systemProperty java.version}</th>
 715      *     <td>Java Runtime Environment version, which may be interpreted
 716      *     as a {@link Runtime.Version}</td></tr>
 717      * <tr><th scope="row">{@systemProperty java.version.date}</th>
 718      *     <td>Java Runtime Environment version date, in ISO-8601 YYYY-MM-DD
 719      *     format, which may be interpreted as a {@link
 720      *     java.time.LocalDate}</td></tr>
 721      * <tr><th scope="row">{@systemProperty java.vendor}</th>
 722      *     <td>Java Runtime Environment vendor</td></tr>
 723      * <tr><th scope="row">{@systemProperty java.vendor.url}</th>
 724      *     <td>Java vendor URL</td></tr>
 725      * <tr><th scope="row">{@systemProperty java.vendor.version}</th>
 726      *     <td>Java vendor version <em>(optional)</em> </td></tr>
 727      * <tr><th scope="row">{@systemProperty java.home}</th>
 728      *     <td>Java installation directory</td></tr>
 729      * <tr><th scope="row">{@systemProperty java.vm.specification.version}</th>
 730      *     <td>Java Virtual Machine specification version, whose value is the
 731      *     {@linkplain Runtime.Version#feature feature} element of the
 732      *     {@linkplain Runtime#version() runtime version}</td></tr>
 733      * <tr><th scope="row">{@systemProperty java.vm.specification.vendor}</th>
 734      *     <td>Java Virtual Machine specification vendor</td></tr>
 735      * <tr><th scope="row">{@systemProperty java.vm.specification.name}</th>
 736      *     <td>Java Virtual Machine specification name</td></tr>
 737      * <tr><th scope="row">{@systemProperty java.vm.version}</th>
 738      *     <td>Java Virtual Machine implementation version which may be
 739      *     interpreted as a {@link Runtime.Version}</td></tr>
 740      * <tr><th scope="row">{@systemProperty java.vm.vendor}</th>
 741      *     <td>Java Virtual Machine implementation vendor</td></tr>
 742      * <tr><th scope="row">{@systemProperty java.vm.name}</th>
 743      *     <td>Java Virtual Machine implementation name</td></tr>
 744      * <tr><th scope="row">{@systemProperty java.specification.version}</th>
 745      *     <td>Java Runtime Environment specification version, whose value is
 746      *     the {@linkplain Runtime.Version#feature feature} element of the
 747      *     {@linkplain Runtime#version() runtime version}</td></tr>
 748      * <tr><th scope="row">{@systemProperty java.specification.maintenance.version}</th>
 749      *     <td>Java Runtime Environment specification maintenance version,
 750      *     may be interpreted as a positive integer <em>(optional, see below)</em></td></tr>
 751      * <tr><th scope="row">{@systemProperty java.specification.vendor}</th>
 752      *     <td>Java Runtime Environment specification  vendor</td></tr>
 753      * <tr><th scope="row">{@systemProperty java.specification.name}</th>
 754      *     <td>Java Runtime Environment specification  name</td></tr>
 755      * <tr><th scope="row">{@systemProperty java.class.version}</th>
 756      *     <td>Java class format version number</td></tr>
 757      * <tr><th scope="row">{@systemProperty java.class.path}</th>
 758      *     <td>Java class path  (refer to
 759      *        {@link ClassLoader#getSystemClassLoader()} for details)</td></tr>
 760      * <tr><th scope="row">{@systemProperty java.library.path}</th>
 761      *     <td>List of paths to search when loading libraries</td></tr>
 762      * <tr><th scope="row">{@systemProperty java.io.tmpdir}</th>
 763      *     <td>Default temp file path</td></tr>
 764      * <tr><th scope="row">{@systemProperty java.compiler}</th>
 765      *     <td>Name of JIT compiler to use</td></tr>
 766      * <tr><th scope="row">{@systemProperty os.name}</th>
 767      *     <td>Operating system name</td></tr>
 768      * <tr><th scope="row">{@systemProperty os.arch}</th>
 769      *     <td>Operating system architecture</td></tr>
 770      * <tr><th scope="row">{@systemProperty os.version}</th>
 771      *     <td>Operating system version</td></tr>
 772      * <tr><th scope="row">{@systemProperty file.separator}</th>
 773      *     <td>File separator ("/" on UNIX)</td></tr>
 774      * <tr><th scope="row">{@systemProperty path.separator}</th>
 775      *     <td>Path separator (":" on UNIX)</td></tr>
 776      * <tr><th scope="row">{@systemProperty line.separator}</th>
 777      *     <td>Line separator ("\n" on UNIX)</td></tr>
 778      * <tr><th scope="row">{@systemProperty user.name}</th>
 779      *     <td>User's account name</td></tr>
 780      * <tr><th scope="row">{@systemProperty user.home}</th>
 781      *     <td>User's home directory</td></tr>
 782      * <tr><th scope="row">{@systemProperty user.dir}</th>
 783      *     <td>User's current working directory</td></tr>
 784      * <tr><th scope="row">{@systemProperty native.encoding}</th>
 785      *     <td>Character encoding name derived from the host environment and/or
 786      *     the user's settings. Setting this system property has no effect.</td></tr>
 787      * <tr><th scope="row">{@systemProperty stdout.encoding}</th>
 788      *     <td>Character encoding name for {@link System#out System.out}.
 789      *     The Java runtime can be started with the system property set to {@code UTF-8},
 790      *     starting it with the property set to another value leads to undefined behavior.
 791      * <tr><th scope="row">{@systemProperty stderr.encoding}</th>
 792      *     <td>Character encoding name for {@link System#err System.err}.
 793      *     The Java runtime can be started with the system property set to {@code UTF-8},
 794      *     starting it with the property set to another value leads to undefined behavior.
 795      * </tbody>
 796      * </table>
 797      * <p>
 798      * The {@code java.specification.maintenance.version} property is
 799      * defined if the specification implemented by this runtime at the
 800      * time of its construction had undergone a <a
 801      * href="https://jcp.org/en/procedures/jcp2#3.6.4">maintenance
 802      * release</a>. When defined, its value identifies that
 803      * maintenance release. To indicate the first maintenance release
 804      * this property will have the value {@code "1"}, to indicate the
 805      * second maintenance release this property will have the value
 806      * {@code "2"}, and so on.
 807      * <p>
 808      * Multiple paths in a system property value are separated by the path
 809      * separator character of the platform.
 810      * <p>
 811      * Note that even if the security manager does not permit the
 812      * {@code getProperties} operation, it may choose to permit the
 813      * {@link #getProperty(String)} operation.
 814      *
 815      * @apiNote
 816      * <strong>Changing a standard system property may have unpredictable results
 817      * unless otherwise specified.</strong>
 818      * Property values may be cached during initialization or on first use.
 819      * Setting a standard property after initialization using {@link #getProperties()},
 820      * {@link #setProperties(Properties)}, {@link #setProperty(String, String)}, or
 821      * {@link #clearProperty(String)} may not have the desired effect.
 822      *
 823      * @implNote
 824      * In addition to the standard system properties, the system
 825      * properties may include the following keys:
 826      * <table class="striped">
 827      * <caption style="display:none">Shows property keys and associated values</caption>
 828      * <thead>
 829      * <tr><th scope="col">Key</th>
 830      *     <th scope="col">Description of Associated Value</th></tr>
 831      * </thead>
 832      * <tbody>
 833      * <tr><th scope="row">{@systemProperty jdk.module.path}</th>
 834      *     <td>The application module path</td></tr>
 835      * <tr><th scope="row">{@systemProperty jdk.module.upgrade.path}</th>
 836      *     <td>The upgrade module path</td></tr>
 837      * <tr><th scope="row">{@systemProperty jdk.module.main}</th>
 838      *     <td>The module name of the initial/main module</td></tr>
 839      * <tr><th scope="row">{@systemProperty jdk.module.main.class}</th>
 840      *     <td>The main class name of the initial module</td></tr>
 841      * <tr><th scope="row">{@systemProperty file.encoding}</th>
 842      *     <td>The name of the default charset, defaults to {@code UTF-8}.
 843      *     The property may be set on the command line to the value
 844      *     {@code UTF-8} or {@code COMPAT}. If set on the command line to
 845      *     the value {@code COMPAT} then the value is replaced with the
 846      *     value of the {@code native.encoding} property during startup.
 847      *     Setting the property to a value other than {@code UTF-8} or
 848      *     {@code COMPAT} leads to unspecified behavior.
 849      *     </td></tr>
 850      * </tbody>
 851      * </table>
 852      *
 853      * @return     the system properties
 854      * @throws     SecurityException  if a security manager exists and its
 855      *             {@code checkPropertiesAccess} method doesn't allow access
 856      *             to the system properties.
 857      * @see        #setProperties
 858      * @see        java.lang.SecurityException
 859      * @see        java.lang.SecurityManager#checkPropertiesAccess()
 860      * @see        java.util.Properties
 861      */
 862     public static Properties getProperties() {
 863         @SuppressWarnings("removal")
 864         SecurityManager sm = getSecurityManager();
 865         if (sm != null) {
 866             sm.checkPropertiesAccess();
 867         }
 868 
 869         return props;
 870     }
 871 
 872     /**
 873      * Returns the system-dependent line separator string.  It always
 874      * returns the same value - the initial value of the {@linkplain
 875      * #getProperty(String) system property} {@code line.separator}.
 876      *
 877      * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
 878      * Windows systems it returns {@code "\r\n"}.
 879      *
 880      * @return the system-dependent line separator string
 881      * @since 1.7
 882      */
 883     public static String lineSeparator() {
 884         return lineSeparator;
 885     }
 886 
 887     private static String lineSeparator;
 888 
 889     /**
 890      * Sets the system properties to the {@code Properties} argument.
 891      *
 892      * First, if there is a security manager, its
 893      * {@code checkPropertiesAccess} method is called with no
 894      * arguments. This may result in a security exception.
 895      * <p>
 896      * The argument becomes the current set of system properties for use
 897      * by the {@link #getProperty(String)} method. If the argument is
 898      * {@code null}, then the current set of system properties is
 899      * forgotten.
 900      *
 901      * @apiNote
 902      * <strong>Changing a standard system property may have unpredictable results
 903      * unless otherwise specified</strong>.
 904      * See {@linkplain #getProperties getProperties} for details.
 905      *
 906      * @param      props   the new system properties.
 907      * @throws     SecurityException  if a security manager exists and its
 908      *             {@code checkPropertiesAccess} method doesn't allow access
 909      *             to the system properties.
 910      * @see        #getProperties
 911      * @see        java.util.Properties
 912      * @see        java.lang.SecurityException
 913      * @see        java.lang.SecurityManager#checkPropertiesAccess()
 914      */
 915     public static void setProperties(Properties props) {
 916         @SuppressWarnings("removal")
 917         SecurityManager sm = getSecurityManager();
 918         if (sm != null) {
 919             sm.checkPropertiesAccess();
 920         }
 921 
 922         if (props == null) {
 923             Map<String, String> tempProps = SystemProps.initProperties();
 924             VersionProps.init(tempProps);
 925             props = createProperties(tempProps);
 926         }
 927         System.props = props;
 928     }
 929 
 930     /**
 931      * Gets the system property indicated by the specified key.
 932      *
 933      * First, if there is a security manager, its
 934      * {@code checkPropertyAccess} method is called with the key as
 935      * its argument. This may result in a SecurityException.
 936      * <p>
 937      * If there is no current set of system properties, a set of system
 938      * properties is first created and initialized in the same manner as
 939      * for the {@code getProperties} method.
 940      *
 941      * @apiNote
 942      * <strong>Changing a standard system property may have unpredictable results
 943      * unless otherwise specified</strong>.
 944      * See {@linkplain #getProperties getProperties} for details.
 945      *
 946      * @param      key   the name of the system property.
 947      * @return     the string value of the system property,
 948      *             or {@code null} if there is no property with that key.
 949      *
 950      * @throws     SecurityException  if a security manager exists and its
 951      *             {@code checkPropertyAccess} method doesn't allow
 952      *             access to the specified system property.
 953      * @throws     NullPointerException if {@code key} is {@code null}.
 954      * @throws     IllegalArgumentException if {@code key} is empty.
 955      * @see        #setProperty
 956      * @see        java.lang.SecurityException
 957      * @see        java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
 958      * @see        java.lang.System#getProperties()
 959      */
 960     public static String getProperty(String key) {
 961         checkKey(key);
 962         @SuppressWarnings("removal")
 963         SecurityManager sm = getSecurityManager();
 964         if (sm != null) {
 965             sm.checkPropertyAccess(key);
 966         }
 967 
 968         return props.getProperty(key);
 969     }
 970 
 971     /**
 972      * Gets the system property indicated by the specified key.
 973      *
 974      * First, if there is a security manager, its
 975      * {@code checkPropertyAccess} method is called with the
 976      * {@code key} as its argument.
 977      * <p>
 978      * If there is no current set of system properties, a set of system
 979      * properties is first created and initialized in the same manner as
 980      * for the {@code getProperties} method.
 981      *
 982      * @param      key   the name of the system property.
 983      * @param      def   a default value.
 984      * @return     the string value of the system property,
 985      *             or the default value if there is no property with that key.
 986      *
 987      * @throws     SecurityException  if a security manager exists and its
 988      *             {@code checkPropertyAccess} method doesn't allow
 989      *             access to the specified system property.
 990      * @throws     NullPointerException if {@code key} is {@code null}.
 991      * @throws     IllegalArgumentException if {@code key} is empty.
 992      * @see        #setProperty
 993      * @see        java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
 994      * @see        java.lang.System#getProperties()
 995      */
 996     public static String getProperty(String key, String def) {
 997         checkKey(key);
 998         @SuppressWarnings("removal")
 999         SecurityManager sm = getSecurityManager();
1000         if (sm != null) {
1001             sm.checkPropertyAccess(key);
1002         }
1003 
1004         return props.getProperty(key, def);
1005     }
1006 
1007     /**
1008      * Sets the system property indicated by the specified key.
1009      *
1010      * First, if a security manager exists, its
1011      * {@code SecurityManager.checkPermission} method
1012      * is called with a {@code PropertyPermission(key, "write")}
1013      * permission. This may result in a SecurityException being thrown.
1014      * If no exception is thrown, the specified property is set to the given
1015      * value.
1016      *
1017      * @apiNote
1018      * <strong>Changing a standard system property may have unpredictable results
1019      * unless otherwise specified</strong>.
1020      * See {@linkplain #getProperties getProperties} for details.
1021      *
1022      * @param      key   the name of the system property.
1023      * @param      value the value of the system property.
1024      * @return     the previous value of the system property,
1025      *             or {@code null} if it did not have one.
1026      *
1027      * @throws     SecurityException  if a security manager exists and its
1028      *             {@code checkPermission} method doesn't allow
1029      *             setting of the specified property.
1030      * @throws     NullPointerException if {@code key} or
1031      *             {@code value} is {@code null}.
1032      * @throws     IllegalArgumentException if {@code key} is empty.
1033      * @see        #getProperty
1034      * @see        java.lang.System#getProperty(java.lang.String)
1035      * @see        java.lang.System#getProperty(java.lang.String, java.lang.String)
1036      * @see        java.util.PropertyPermission
1037      * @see        SecurityManager#checkPermission
1038      * @since      1.2
1039      */
1040     public static String setProperty(String key, String value) {
1041         checkKey(key);
1042         @SuppressWarnings("removal")
1043         SecurityManager sm = getSecurityManager();
1044         if (sm != null) {
1045             sm.checkPermission(new PropertyPermission(key,
1046                 SecurityConstants.PROPERTY_WRITE_ACTION));
1047         }
1048 
1049         return (String) props.setProperty(key, value);
1050     }
1051 
1052     /**
1053      * Removes the system property indicated by the specified key.
1054      *
1055      * First, if a security manager exists, its
1056      * {@code SecurityManager.checkPermission} method
1057      * is called with a {@code PropertyPermission(key, "write")}
1058      * permission. This may result in a SecurityException being thrown.
1059      * If no exception is thrown, the specified property is removed.
1060      *
1061      * @apiNote
1062      * <strong>Changing a standard system property may have unpredictable results
1063      * unless otherwise specified</strong>.
1064      * See {@linkplain #getProperties getProperties} method for details.
1065      *
1066      * @param      key   the name of the system property to be removed.
1067      * @return     the previous string value of the system property,
1068      *             or {@code null} if there was no property with that key.
1069      *
1070      * @throws     SecurityException  if a security manager exists and its
1071      *             {@code checkPropertyAccess} method doesn't allow
1072      *              access to the specified system property.
1073      * @throws     NullPointerException if {@code key} is {@code null}.
1074      * @throws     IllegalArgumentException if {@code key} is empty.
1075      * @see        #getProperty
1076      * @see        #setProperty
1077      * @see        java.util.Properties
1078      * @see        java.lang.SecurityException
1079      * @see        java.lang.SecurityManager#checkPropertiesAccess()
1080      * @since 1.5
1081      */
1082     public static String clearProperty(String key) {
1083         checkKey(key);
1084         @SuppressWarnings("removal")
1085         SecurityManager sm = getSecurityManager();
1086         if (sm != null) {
1087             sm.checkPermission(new PropertyPermission(key, "write"));
1088         }
1089 
1090         return (String) props.remove(key);
1091     }
1092 
1093     private static void checkKey(String key) {
1094         if (key == null) {
1095             throw new NullPointerException("key can't be null");
1096         }
1097         if (key.isEmpty()) {
1098             throw new IllegalArgumentException("key can't be empty");
1099         }
1100     }
1101 
1102     /**
1103      * Gets the value of the specified environment variable. An
1104      * environment variable is a system-dependent external named
1105      * value.
1106      *
1107      * <p>If a security manager exists, its
1108      * {@link SecurityManager#checkPermission checkPermission}
1109      * method is called with a
1110      * {@link RuntimePermission RuntimePermission("getenv."+name)}
1111      * permission.  This may result in a {@link SecurityException}
1112      * being thrown.  If no exception is thrown the value of the
1113      * variable {@code name} is returned.
1114      *
1115      * <p><a id="EnvironmentVSSystemProperties"><i>System
1116      * properties</i> and <i>environment variables</i></a> are both
1117      * conceptually mappings between names and values.  Both
1118      * mechanisms can be used to pass user-defined information to a
1119      * Java process.  Environment variables have a more global effect,
1120      * because they are visible to all descendants of the process
1121      * which defines them, not just the immediate Java subprocess.
1122      * They can have subtly different semantics, such as case
1123      * insensitivity, on different operating systems.  For these
1124      * reasons, environment variables are more likely to have
1125      * unintended side effects.  It is best to use system properties
1126      * where possible.  Environment variables should be used when a
1127      * global effect is desired, or when an external system interface
1128      * requires an environment variable (such as {@code PATH}).
1129      *
1130      * <p>On UNIX systems the alphabetic case of {@code name} is
1131      * typically significant, while on Microsoft Windows systems it is
1132      * typically not.  For example, the expression
1133      * {@code System.getenv("FOO").equals(System.getenv("foo"))}
1134      * is likely to be true on Microsoft Windows.
1135      *
1136      * @param  name the name of the environment variable
1137      * @return the string value of the variable, or {@code null}
1138      *         if the variable is not defined in the system environment
1139      * @throws NullPointerException if {@code name} is {@code null}
1140      * @throws SecurityException
1141      *         if a security manager exists and its
1142      *         {@link SecurityManager#checkPermission checkPermission}
1143      *         method doesn't allow access to the environment variable
1144      *         {@code name}
1145      * @see    #getenv()
1146      * @see    ProcessBuilder#environment()
1147      */
1148     public static String getenv(String name) {
1149         @SuppressWarnings("removal")
1150         SecurityManager sm = getSecurityManager();
1151         if (sm != null) {
1152             sm.checkPermission(new RuntimePermission("getenv."+name));
1153         }
1154 
1155         return ProcessEnvironment.getenv(name);
1156     }
1157 
1158 
1159     /**
1160      * Returns an unmodifiable string map view of the current system environment.
1161      * The environment is a system-dependent mapping from names to
1162      * values which is passed from parent to child processes.
1163      *
1164      * <p>If the system does not support environment variables, an
1165      * empty map is returned.
1166      *
1167      * <p>The returned map will never contain null keys or values.
1168      * Attempting to query the presence of a null key or value will
1169      * throw a {@link NullPointerException}.  Attempting to query
1170      * the presence of a key or value which is not of type
1171      * {@link String} will throw a {@link ClassCastException}.
1172      *
1173      * <p>The returned map and its collection views may not obey the
1174      * general contract of the {@link Object#equals} and
1175      * {@link Object#hashCode} methods.
1176      *
1177      * <p>The returned map is typically case-sensitive on all platforms.
1178      *
1179      * <p>If a security manager exists, its
1180      * {@link SecurityManager#checkPermission checkPermission}
1181      * method is called with a
1182      * {@link RuntimePermission RuntimePermission("getenv.*")} permission.
1183      * This may result in a {@link SecurityException} being thrown.
1184      *
1185      * <p>When passing information to a Java subprocess,
1186      * <a href=#EnvironmentVSSystemProperties>system properties</a>
1187      * are generally preferred over environment variables.
1188      *
1189      * @return the environment as a map of variable names to values
1190      * @throws SecurityException
1191      *         if a security manager exists and its
1192      *         {@link SecurityManager#checkPermission checkPermission}
1193      *         method doesn't allow access to the process environment
1194      * @see    #getenv(String)
1195      * @see    ProcessBuilder#environment()
1196      * @since  1.5
1197      */
1198     public static java.util.Map<String,String> getenv() {
1199         @SuppressWarnings("removal")
1200         SecurityManager sm = getSecurityManager();
1201         if (sm != null) {
1202             sm.checkPermission(new RuntimePermission("getenv.*"));
1203         }
1204 
1205         return ProcessEnvironment.getenv();
1206     }
1207 
1208     /**
1209      * {@code System.Logger} instances log messages that will be
1210      * routed to the underlying logging framework the {@link System.LoggerFinder
1211      * LoggerFinder} uses.
1212      *
1213      * {@code System.Logger} instances are typically obtained from
1214      * the {@link java.lang.System System} class, by calling
1215      * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
1216      * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1217      * System.getLogger(loggerName, bundle)}.
1218      *
1219      * @see java.lang.System#getLogger(java.lang.String)
1220      * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1221      * @see java.lang.System.LoggerFinder
1222      *
1223      * @since 9
1224      */
1225     public interface Logger {
1226 
1227         /**
1228          * System {@linkplain Logger loggers} levels.
1229          *
1230          * A level has a {@linkplain #getName() name} and {@linkplain
1231          * #getSeverity() severity}.
1232          * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
1233          * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
1234          * by order of increasing severity.
1235          * <br>
1236          * {@link #ALL} and {@link #OFF}
1237          * are simple markers with severities mapped respectively to
1238          * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
1239          * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
1240          * <p>
1241          * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
1242          * <p>
1243          * {@linkplain System.Logger.Level System logger levels} are mapped to
1244          * {@linkplain java.logging/java.util.logging.Level  java.util.logging levels}
1245          * of corresponding severity.
1246          * <br>The mapping is as follows:
1247          * <br><br>
1248          * <table class="striped">
1249          * <caption>System.Logger Severity Level Mapping</caption>
1250          * <thead>
1251          * <tr><th scope="col">System.Logger Levels</th>
1252          *     <th scope="col">java.util.logging Levels</th>
1253          * </thead>
1254          * <tbody>
1255          * <tr><th scope="row">{@link Logger.Level#ALL ALL}</th>
1256          *     <td>{@link java.logging/java.util.logging.Level#ALL ALL}</td>
1257          * <tr><th scope="row">{@link Logger.Level#TRACE TRACE}</th>
1258          *     <td>{@link java.logging/java.util.logging.Level#FINER FINER}</td>
1259          * <tr><th scope="row">{@link Logger.Level#DEBUG DEBUG}</th>
1260          *     <td>{@link java.logging/java.util.logging.Level#FINE FINE}</td>
1261          * <tr><th scope="row">{@link Logger.Level#INFO INFO}</th>
1262          *     <td>{@link java.logging/java.util.logging.Level#INFO INFO}</td>
1263          * <tr><th scope="row">{@link Logger.Level#WARNING WARNING}</th>
1264          *     <td>{@link java.logging/java.util.logging.Level#WARNING WARNING}</td>
1265          * <tr><th scope="row">{@link Logger.Level#ERROR ERROR}</th>
1266          *     <td>{@link java.logging/java.util.logging.Level#SEVERE SEVERE}</td>
1267          * <tr><th scope="row">{@link Logger.Level#OFF OFF}</th>
1268          *     <td>{@link java.logging/java.util.logging.Level#OFF OFF}</td>
1269          * </tbody>
1270          * </table>
1271          *
1272          * @since 9
1273          *
1274          * @see java.lang.System.LoggerFinder
1275          * @see java.lang.System.Logger
1276          */
1277         @SuppressWarnings("doclint:reference") // cross-module links
1278         public enum Level {
1279 
1280             // for convenience, we're reusing java.util.logging.Level int values
1281             // the mapping logic in sun.util.logging.PlatformLogger depends
1282             // on this.
1283             /**
1284              * A marker to indicate that all levels are enabled.
1285              * This level {@linkplain #getSeverity() severity} is
1286              * {@link Integer#MIN_VALUE}.
1287              */
1288             ALL(Integer.MIN_VALUE),  // typically mapped to/from j.u.l.Level.ALL
1289             /**
1290              * {@code TRACE} level: usually used to log diagnostic information.
1291              * This level {@linkplain #getSeverity() severity} is
1292              * {@code 400}.
1293              */
1294             TRACE(400),   // typically mapped to/from j.u.l.Level.FINER
1295             /**
1296              * {@code DEBUG} level: usually used to log debug information traces.
1297              * This level {@linkplain #getSeverity() severity} is
1298              * {@code 500}.
1299              */
1300             DEBUG(500),   // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1301             /**
1302              * {@code INFO} level: usually used to log information messages.
1303              * This level {@linkplain #getSeverity() severity} is
1304              * {@code 800}.
1305              */
1306             INFO(800),    // typically mapped to/from j.u.l.Level.INFO
1307             /**
1308              * {@code WARNING} level: usually used to log warning messages.
1309              * This level {@linkplain #getSeverity() severity} is
1310              * {@code 900}.
1311              */
1312             WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1313             /**
1314              * {@code ERROR} level: usually used to log error messages.
1315              * This level {@linkplain #getSeverity() severity} is
1316              * {@code 1000}.
1317              */
1318             ERROR(1000),  // typically mapped to/from j.u.l.Level.SEVERE
1319             /**
1320              * A marker to indicate that all levels are disabled.
1321              * This level {@linkplain #getSeverity() severity} is
1322              * {@link Integer#MAX_VALUE}.
1323              */
1324             OFF(Integer.MAX_VALUE);  // typically mapped to/from j.u.l.Level.OFF
1325 
1326             private final int severity;
1327 
1328             private Level(int severity) {
1329                 this.severity = severity;
1330             }
1331 
1332             /**
1333              * Returns the name of this level.
1334              * @return this level {@linkplain #name()}.
1335              */
1336             public final String getName() {
1337                 return name();
1338             }
1339 
1340             /**
1341              * Returns the severity of this level.
1342              * A higher severity means a more severe condition.
1343              * @return this level severity.
1344              */
1345             public final int getSeverity() {
1346                 return severity;
1347             }
1348         }
1349 
1350         /**
1351          * Returns the name of this logger.
1352          *
1353          * @return the logger name.
1354          */
1355         public String getName();
1356 
1357         /**
1358          * Checks if a message of the given level would be logged by
1359          * this logger.
1360          *
1361          * @param level the log message level.
1362          * @return {@code true} if the given log message level is currently
1363          *         being logged.
1364          *
1365          * @throws NullPointerException if {@code level} is {@code null}.
1366          */
1367         public boolean isLoggable(Level level);
1368 
1369         /**
1370          * Logs a message.
1371          *
1372          * @implSpec The default implementation for this method calls
1373          * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1374          *
1375          * @param level the log message level.
1376          * @param msg the string message (or a key in the message catalog, if
1377          * this logger is a {@link
1378          * LoggerFinder#getLocalizedLogger(java.lang.String,
1379          * java.util.ResourceBundle, java.lang.Module) localized logger});
1380          * can be {@code null}.
1381          *
1382          * @throws NullPointerException if {@code level} is {@code null}.
1383          */
1384         public default void log(Level level, String msg) {
1385             log(level, (ResourceBundle) null, msg, (Object[]) null);
1386         }
1387 
1388         /**
1389          * Logs a lazily supplied message.
1390          *
1391          * If the logger is currently enabled for the given log message level
1392          * then a message is logged that is the result produced by the
1393          * given supplier function.  Otherwise, the supplier is not operated on.
1394          *
1395          * @implSpec When logging is enabled for the given level, the default
1396          * implementation for this method calls
1397          * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1398          *
1399          * @param level the log message level.
1400          * @param msgSupplier a supplier function that produces a message.
1401          *
1402          * @throws NullPointerException if {@code level} is {@code null},
1403          *         or {@code msgSupplier} is {@code null}.
1404          */
1405         public default void log(Level level, Supplier<String> msgSupplier) {
1406             Objects.requireNonNull(msgSupplier);
1407             if (isLoggable(Objects.requireNonNull(level))) {
1408                 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1409             }
1410         }
1411 
1412         /**
1413          * Logs a message produced from the given object.
1414          *
1415          * If the logger is currently enabled for the given log message level then
1416          * a message is logged that, by default, is the result produced from
1417          * calling  toString on the given object.
1418          * Otherwise, the object is not operated on.
1419          *
1420          * @implSpec When logging is enabled for the given level, the default
1421          * implementation for this method calls
1422          * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1423          *
1424          * @param level the log message level.
1425          * @param obj the object to log.
1426          *
1427          * @throws NullPointerException if {@code level} is {@code null}, or
1428          *         {@code obj} is {@code null}.
1429          */
1430         public default void log(Level level, Object obj) {
1431             Objects.requireNonNull(obj);
1432             if (isLoggable(Objects.requireNonNull(level))) {
1433                 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1434             }
1435         }
1436 
1437         /**
1438          * Logs a message associated with a given throwable.
1439          *
1440          * @implSpec The default implementation for this method calls
1441          * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1442          *
1443          * @param level the log message level.
1444          * @param msg the string message (or a key in the message catalog, if
1445          * this logger is a {@link
1446          * LoggerFinder#getLocalizedLogger(java.lang.String,
1447          * java.util.ResourceBundle, java.lang.Module) localized logger});
1448          * can be {@code null}.
1449          * @param thrown a {@code Throwable} associated with the log message;
1450          *        can be {@code null}.
1451          *
1452          * @throws NullPointerException if {@code level} is {@code null}.
1453          */
1454         public default void log(Level level, String msg, Throwable thrown) {
1455             this.log(level, null, msg, thrown);
1456         }
1457 
1458         /**
1459          * Logs a lazily supplied message associated with a given throwable.
1460          *
1461          * If the logger is currently enabled for the given log message level
1462          * then a message is logged that is the result produced by the
1463          * given supplier function.  Otherwise, the supplier is not operated on.
1464          *
1465          * @implSpec When logging is enabled for the given level, the default
1466          * implementation for this method calls
1467          * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1468          *
1469          * @param level one of the log message level identifiers.
1470          * @param msgSupplier a supplier function that produces a message.
1471          * @param thrown a {@code Throwable} associated with log message;
1472          *               can be {@code null}.
1473          *
1474          * @throws NullPointerException if {@code level} is {@code null}, or
1475          *                               {@code msgSupplier} is {@code null}.
1476          */
1477         public default void log(Level level, Supplier<String> msgSupplier,
1478                 Throwable thrown) {
1479             Objects.requireNonNull(msgSupplier);
1480             if (isLoggable(Objects.requireNonNull(level))) {
1481                 this.log(level, null, msgSupplier.get(), thrown);
1482             }
1483         }
1484 
1485         /**
1486          * Logs a message with an optional list of parameters.
1487          *
1488          * @implSpec The default implementation for this method calls
1489          * {@code this.log(level, (ResourceBundle)null, format, params);}
1490          *
1491          * @param level one of the log message level identifiers.
1492          * @param format the string message format in {@link
1493          * java.text.MessageFormat} format, (or a key in the message
1494          * catalog, if this logger is a {@link
1495          * LoggerFinder#getLocalizedLogger(java.lang.String,
1496          * java.util.ResourceBundle, java.lang.Module) localized logger});
1497          * can be {@code null}.
1498          * @param params an optional list of parameters to the message (may be
1499          * none).
1500          *
1501          * @throws NullPointerException if {@code level} is {@code null}.
1502          */
1503         public default void log(Level level, String format, Object... params) {
1504             this.log(level, null, format, params);
1505         }
1506 
1507         /**
1508          * Logs a localized message associated with a given throwable.
1509          *
1510          * If the given resource bundle is non-{@code null},  the {@code msg}
1511          * string is localized using the given resource bundle.
1512          * Otherwise the {@code msg} string is not localized.
1513          *
1514          * @param level the log message level.
1515          * @param bundle a resource bundle to localize {@code msg}; can be
1516          * {@code null}.
1517          * @param msg the string message (or a key in the message catalog,
1518          *            if {@code bundle} is not {@code null}); can be {@code null}.
1519          * @param thrown a {@code Throwable} associated with the log message;
1520          *        can be {@code null}.
1521          *
1522          * @throws NullPointerException if {@code level} is {@code null}.
1523          */
1524         public void log(Level level, ResourceBundle bundle, String msg,
1525                 Throwable thrown);
1526 
1527         /**
1528          * Logs a message with resource bundle and an optional list of
1529          * parameters.
1530          *
1531          * If the given resource bundle is non-{@code null},  the {@code format}
1532          * string is localized using the given resource bundle.
1533          * Otherwise the {@code format} string is not localized.
1534          *
1535          * @param level the log message level.
1536          * @param bundle a resource bundle to localize {@code format}; can be
1537          * {@code null}.
1538          * @param format the string message format in {@link
1539          * java.text.MessageFormat} format, (or a key in the message
1540          * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1541          * @param params an optional list of parameters to the message (may be
1542          * none).
1543          *
1544          * @throws NullPointerException if {@code level} is {@code null}.
1545          */
1546         public void log(Level level, ResourceBundle bundle, String format,
1547                 Object... params);
1548     }
1549 
1550     /**
1551      * The {@code LoggerFinder} service is responsible for creating, managing,
1552      * and configuring loggers to the underlying framework it uses.
1553      *
1554      * A logger finder is a concrete implementation of this class that has a
1555      * zero-argument constructor and implements the abstract methods defined
1556      * by this class.
1557      * The loggers returned from a logger finder are capable of routing log
1558      * messages to the logging backend this provider supports.
1559      * A given invocation of the Java Runtime maintains a single
1560      * system-wide LoggerFinder instance that is loaded as follows:
1561      * <ul>
1562      *    <li>First it finds any custom {@code LoggerFinder} provider
1563      *        using the {@link java.util.ServiceLoader} facility with the
1564      *        {@linkplain ClassLoader#getSystemClassLoader() system class
1565      *        loader}.</li>
1566      *    <li>If no {@code LoggerFinder} provider is found, the system default
1567      *        {@code LoggerFinder} implementation will be used.</li>
1568      * </ul>
1569      * <p>
1570      * An application can replace the logging backend
1571      * <i>even when the java.logging module is present</i>, by simply providing
1572      * and declaring an implementation of the {@link LoggerFinder} service.
1573      * <p>
1574      * <b>Default Implementation</b>
1575      * <p>
1576      * The system default {@code LoggerFinder} implementation uses
1577      * {@code java.util.logging} as the backend framework when the
1578      * {@code java.logging} module is present.
1579      * It returns a {@linkplain System.Logger logger} instance
1580      * that will route log messages to a {@link java.logging/java.util.logging.Logger
1581      * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1582      * present, the default implementation will return a simple logger
1583      * instance that will route log messages of {@code INFO} level and above to
1584      * the console ({@code System.err}).
1585      * <p>
1586      * <b>Logging Configuration</b>
1587      * <p>
1588      * {@linkplain Logger Logger} instances obtained from the
1589      * {@code LoggerFinder} factory methods are not directly configurable by
1590      * the application. Configuration is the responsibility of the underlying
1591      * logging backend, and usually requires using APIs specific to that backend.
1592      * <p>For the default {@code LoggerFinder} implementation
1593      * using {@code java.util.logging} as its backend, refer to
1594      * {@link java.logging/java.util.logging java.util.logging} for logging configuration.
1595      * For the default {@code LoggerFinder} implementation returning simple loggers
1596      * when the {@code java.logging} module is absent, the configuration
1597      * is implementation dependent.
1598      * <p>
1599      * Usually an application that uses a logging framework will log messages
1600      * through a logger facade defined (or supported) by that framework.
1601      * Applications that wish to use an external framework should log
1602      * through the facade associated with that framework.
1603      * <p>
1604      * A system class that needs to log messages will typically obtain
1605      * a {@link System.Logger} instance to route messages to the logging
1606      * framework selected by the application.
1607      * <p>
1608      * Libraries and classes that only need loggers to produce log messages
1609      * should not attempt to configure loggers by themselves, as that
1610      * would make them dependent from a specific implementation of the
1611      * {@code LoggerFinder} service.
1612      * <p>
1613      * In addition, when a security manager is present, loggers provided to
1614      * system classes should not be directly configurable through the logging
1615      * backend without requiring permissions.
1616      * <br>
1617      * It is the responsibility of the provider of
1618      * the concrete {@code LoggerFinder} implementation to ensure that
1619      * these loggers are not configured by untrusted code without proper
1620      * permission checks, as configuration performed on such loggers usually
1621      * affects all applications in the same Java Runtime.
1622      * <p>
1623      * <b>Message Levels and Mapping to backend levels</b>
1624      * <p>
1625      * A logger finder is responsible for mapping from a {@code
1626      * System.Logger.Level} to a level supported by the logging backend it uses.
1627      * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1628      * maps {@code System.Logger} levels to
1629      * {@linkplain java.logging/java.util.logging.Level java.util.logging} levels
1630      * of corresponding severity - as described in {@link Logger.Level
1631      * Logger.Level}.
1632      *
1633      * @see java.lang.System
1634      * @see java.lang.System.Logger
1635      *
1636      * @since 9
1637      */
1638     @SuppressWarnings("doclint:reference") // cross-module links
1639     public abstract static class LoggerFinder {
1640         /**
1641          * The {@code RuntimePermission("loggerFinder")} is
1642          * necessary to subclass and instantiate the {@code LoggerFinder} class,
1643          * as well as to obtain loggers from an instance of that class.
1644          */
1645         static final RuntimePermission LOGGERFINDER_PERMISSION =
1646                 new RuntimePermission("loggerFinder");
1647 
1648         /**
1649          * Creates a new instance of {@code LoggerFinder}.
1650          *
1651          * @implNote It is recommended that a {@code LoggerFinder} service
1652          *   implementation does not perform any heavy initialization in its
1653          *   constructor, in order to avoid possible risks of deadlock or class
1654          *   loading cycles during the instantiation of the service provider.
1655          *
1656          * @throws SecurityException if a security manager is present and its
1657          *         {@code checkPermission} method doesn't allow the
1658          *         {@code RuntimePermission("loggerFinder")}.
1659          */
1660         protected LoggerFinder() {
1661             this(checkPermission());
1662         }
1663 
1664         private LoggerFinder(Void unused) {
1665             // nothing to do.
1666         }
1667 
1668         private static Void checkPermission() {
1669             @SuppressWarnings("removal")
1670             final SecurityManager sm = System.getSecurityManager();
1671             if (sm != null) {
1672                 sm.checkPermission(LOGGERFINDER_PERMISSION);
1673             }
1674             return null;
1675         }
1676 
1677         /**
1678          * Returns an instance of {@link Logger Logger}
1679          * for the given {@code module}.
1680          *
1681          * @param name the name of the logger.
1682          * @param module the module for which the logger is being requested.
1683          *
1684          * @return a {@link Logger logger} suitable for use within the given
1685          *         module.
1686          * @throws NullPointerException if {@code name} is {@code null} or
1687          *        {@code module} is {@code null}.
1688          * @throws SecurityException if a security manager is present and its
1689          *         {@code checkPermission} method doesn't allow the
1690          *         {@code RuntimePermission("loggerFinder")}.
1691          */
1692         public abstract Logger getLogger(String name, Module module);
1693 
1694         /**
1695          * Returns a localizable instance of {@link Logger Logger}
1696          * for the given {@code module}.
1697          * The returned logger will use the provided resource bundle for
1698          * message localization.
1699          *
1700          * @implSpec By default, this method calls {@link
1701          * #getLogger(java.lang.String, java.lang.Module)
1702          * this.getLogger(name, module)} to obtain a logger, then wraps that
1703          * logger in a {@link Logger} instance where all methods that do not
1704          * take a {@link ResourceBundle} as parameter are redirected to one
1705          * which does - passing the given {@code bundle} for
1706          * localization. So for instance, a call to {@link
1707          * Logger#log(Logger.Level, String) Logger.log(Level.INFO, msg)}
1708          * will end up as a call to {@link
1709          * Logger#log(Logger.Level, ResourceBundle, String, Object...)
1710          * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1711          * logger instance.
1712          * Note however that by default, string messages returned by {@link
1713          * java.util.function.Supplier Supplier&lt;String&gt;} will not be
1714          * localized, as it is assumed that such strings are messages which are
1715          * already constructed, rather than keys in a resource bundle.
1716          * <p>
1717          * An implementation of {@code LoggerFinder} may override this method,
1718          * for example, when the underlying logging backend provides its own
1719          * mechanism for localizing log messages, then such a
1720          * {@code LoggerFinder} would be free to return a logger
1721          * that makes direct use of the mechanism provided by the backend.
1722          *
1723          * @param name    the name of the logger.
1724          * @param bundle  a resource bundle; can be {@code null}.
1725          * @param module  the module for which the logger is being requested.
1726          * @return an instance of {@link Logger Logger}  which will use the
1727          * provided resource bundle for message localization.
1728          *
1729          * @throws NullPointerException if {@code name} is {@code null} or
1730          *         {@code module} is {@code null}.
1731          * @throws SecurityException if a security manager is present and its
1732          *         {@code checkPermission} method doesn't allow the
1733          *         {@code RuntimePermission("loggerFinder")}.
1734          */
1735         public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1736                                          Module module) {
1737             return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1738         }
1739 
1740         /**
1741          * Returns the {@code LoggerFinder} instance. There is one
1742          * single system-wide {@code LoggerFinder} instance in
1743          * the Java Runtime.  See the class specification of how the
1744          * {@link LoggerFinder LoggerFinder} implementation is located and
1745          * loaded.
1746          *
1747          * @return the {@link LoggerFinder LoggerFinder} instance.
1748          * @throws SecurityException if a security manager is present and its
1749          *         {@code checkPermission} method doesn't allow the
1750          *         {@code RuntimePermission("loggerFinder")}.
1751          */
1752         public static LoggerFinder getLoggerFinder() {
1753             @SuppressWarnings("removal")
1754             final SecurityManager sm = System.getSecurityManager();
1755             if (sm != null) {
1756                 sm.checkPermission(LOGGERFINDER_PERMISSION);
1757             }
1758             return accessProvider();
1759         }
1760 
1761 
1762         private static volatile LoggerFinder service;
1763         @SuppressWarnings("removal")
1764         static LoggerFinder accessProvider() {
1765             // We do not need to synchronize: LoggerFinderLoader will
1766             // always return the same instance, so if we don't have it,
1767             // just fetch it again.
1768             if (service == null) {
1769                 PrivilegedAction<LoggerFinder> pa =
1770                         () -> LoggerFinderLoader.getLoggerFinder();
1771                 service = AccessController.doPrivileged(pa, null,
1772                         LOGGERFINDER_PERMISSION);
1773             }
1774             return service;
1775         }
1776 
1777     }
1778 
1779 
1780     /**
1781      * Returns an instance of {@link Logger Logger} for the caller's
1782      * use.
1783      *
1784      * @implSpec
1785      * Instances returned by this method route messages to loggers
1786      * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1787      * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1788      * {@code module} is the caller's module.
1789      * In cases where {@code System.getLogger} is called from a context where
1790      * there is no caller frame on the stack (e.g when called directly
1791      * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1792      * To obtain a logger in such a context, use an auxiliary class that will
1793      * implicitly be identified as the caller, or use the system {@link
1794      * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1795      * Note that doing the latter may eagerly initialize the underlying
1796      * logging system.
1797      *
1798      * @apiNote
1799      * This method may defer calling the {@link
1800      * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1801      * LoggerFinder.getLogger} method to create an actual logger supplied by
1802      * the logging backend, for instance, to allow loggers to be obtained during
1803      * the system initialization time.
1804      *
1805      * @param name the name of the logger.
1806      * @return an instance of {@link Logger} that can be used by the calling
1807      *         class.
1808      * @throws NullPointerException if {@code name} is {@code null}.
1809      * @throws IllegalCallerException if there is no Java caller frame on the
1810      *         stack.
1811      *
1812      * @since 9
1813      */
1814     @CallerSensitive
1815     public static Logger getLogger(String name) {
1816         Objects.requireNonNull(name);
1817         final Class<?> caller = Reflection.getCallerClass();
1818         if (caller == null) {
1819             throw new IllegalCallerException("no caller frame");
1820         }
1821         return LazyLoggers.getLogger(name, caller.getModule());
1822     }
1823 
1824     /**
1825      * Returns a localizable instance of {@link Logger
1826      * Logger} for the caller's use.
1827      * The returned logger will use the provided resource bundle for message
1828      * localization.
1829      *
1830      * @implSpec
1831      * The returned logger will perform message localization as specified
1832      * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1833      * java.util.ResourceBundle, java.lang.Module)
1834      * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1835      * {@code module} is the caller's module.
1836      * In cases where {@code System.getLogger} is called from a context where
1837      * there is no caller frame on the stack (e.g when called directly
1838      * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1839      * To obtain a logger in such a context, use an auxiliary class that
1840      * will implicitly be identified as the caller, or use the system {@link
1841      * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1842      * Note that doing the latter may eagerly initialize the underlying
1843      * logging system.
1844      *
1845      * @apiNote
1846      * This method is intended to be used after the system is fully initialized.
1847      * This method may trigger the immediate loading and initialization
1848      * of the {@link LoggerFinder} service, which may cause issues if the
1849      * Java Runtime is not ready to initialize the concrete service
1850      * implementation yet.
1851      * System classes which may be loaded early in the boot sequence and
1852      * need to log localized messages should create a logger using
1853      * {@link #getLogger(java.lang.String)} and then use the log methods that
1854      * take a resource bundle as parameter.
1855      *
1856      * @param name    the name of the logger.
1857      * @param bundle  a resource bundle.
1858      * @return an instance of {@link Logger} which will use the provided
1859      * resource bundle for message localization.
1860      * @throws NullPointerException if {@code name} is {@code null} or
1861      *         {@code bundle} is {@code null}.
1862      * @throws IllegalCallerException if there is no Java caller frame on the
1863      *         stack.
1864      *
1865      * @since 9
1866      */
1867     @SuppressWarnings("removal")
1868     @CallerSensitive
1869     public static Logger getLogger(String name, ResourceBundle bundle) {
1870         final ResourceBundle rb = Objects.requireNonNull(bundle);
1871         Objects.requireNonNull(name);
1872         final Class<?> caller = Reflection.getCallerClass();
1873         if (caller == null) {
1874             throw new IllegalCallerException("no caller frame");
1875         }
1876         final SecurityManager sm = System.getSecurityManager();
1877         // We don't use LazyLoggers if a resource bundle is specified.
1878         // Bootstrap sensitive classes in the JDK do not use resource bundles
1879         // when logging. This could be revisited later, if it needs to.
1880         if (sm != null) {
1881             final PrivilegedAction<Logger> pa =
1882                     () -> LoggerFinder.accessProvider()
1883                             .getLocalizedLogger(name, rb, caller.getModule());
1884             return AccessController.doPrivileged(pa, null,
1885                                          LoggerFinder.LOGGERFINDER_PERMISSION);
1886         }
1887         return LoggerFinder.accessProvider()
1888                 .getLocalizedLogger(name, rb, caller.getModule());
1889     }
1890 
1891     /**
1892      * Initiates the <a href="Runtime.html#shutdown">shutdown sequence</a> of the
1893      * Java Virtual Machine. This method always blocks indefinitely. The argument
1894      * serves as a status code; by convention, a nonzero status code indicates
1895      * abnormal termination.
1896      * <p>
1897      * This method calls the {@code exit} method in class {@code Runtime}. This
1898      * method never returns normally.
1899      * <p>
1900      * The call {@code System.exit(n)} is effectively equivalent to the call:
1901      * <blockquote><pre>
1902      * Runtime.getRuntime().exit(n)
1903      * </pre></blockquote>
1904      *
1905      * @param  status exit status.
1906      * @throws SecurityException
1907      *         if a security manager exists and its {@code checkExit} method
1908      *         doesn't allow exit with the specified status.
1909      * @see    java.lang.Runtime#exit(int)
1910      */
1911     public static void exit(int status) {
1912         Runtime.getRuntime().exit(status);
1913     }
1914 
1915     /**
1916      * Runs the garbage collector in the Java Virtual Machine.
1917      * <p>
1918      * Calling the {@code gc} method suggests that the Java Virtual Machine
1919      * expend effort toward recycling unused objects in order to
1920      * make the memory they currently occupy available for reuse
1921      * by the Java Virtual Machine.
1922      * When control returns from the method call, the Java Virtual Machine
1923      * has made a best effort to reclaim space from all unused objects.
1924      * There is no guarantee that this effort will recycle any particular
1925      * number of unused objects, reclaim any particular amount of space, or
1926      * complete at any particular time, if at all, before the method returns or ever.
1927      * There is also no guarantee that this effort will determine
1928      * the change of reachability in any particular number of objects,
1929      * or that any particular number of {@link java.lang.ref.Reference Reference}
1930      * objects will be cleared and enqueued.
1931      *
1932      * <p>
1933      * The call {@code System.gc()} is effectively equivalent to the
1934      * call:
1935      * <blockquote><pre>
1936      * Runtime.getRuntime().gc()
1937      * </pre></blockquote>
1938      *
1939      * @see     java.lang.Runtime#gc()
1940      */
1941     public static void gc() {
1942         Runtime.getRuntime().gc();
1943     }
1944 
1945     /**
1946      * Runs the finalization methods of any objects pending finalization.
1947      *
1948      * Calling this method suggests that the Java Virtual Machine expend
1949      * effort toward running the {@code finalize} methods of objects
1950      * that have been found to be discarded but whose {@code finalize}
1951      * methods have not yet been run. When control returns from the
1952      * method call, the Java Virtual Machine has made a best effort to
1953      * complete all outstanding finalizations.
1954      * <p>
1955      * The call {@code System.runFinalization()} is effectively
1956      * equivalent to the call:
1957      * <blockquote><pre>
1958      * Runtime.getRuntime().runFinalization()
1959      * </pre></blockquote>
1960      *
1961      * @deprecated Finalization has been deprecated for removal.  See
1962      * {@link java.lang.Object#finalize} for background information and details
1963      * about migration options.
1964      * <p>
1965      * When running in a JVM in which finalization has been disabled or removed,
1966      * no objects will be pending finalization, so this method does nothing.
1967      *
1968      * @see     java.lang.Runtime#runFinalization()
1969      * @jls 12.6 Finalization of Class Instances
1970      */
1971     @Deprecated(since="18", forRemoval=true)
1972     @SuppressWarnings("removal")
1973     public static void runFinalization() {
1974         Runtime.getRuntime().runFinalization();
1975     }
1976 
1977     /**
1978      * Loads the native library specified by the filename argument.  The filename
1979      * argument must be an absolute path name.
1980      *
1981      * If the filename argument, when stripped of any platform-specific library
1982      * prefix, path, and file extension, indicates a library whose name is,
1983      * for example, L, and a native library called L is statically linked
1984      * with the VM, then the JNI_OnLoad_L function exported by the library
1985      * is invoked rather than attempting to load a dynamic library.
1986      * A filename matching the argument does not have to exist in the
1987      * file system.
1988      * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1989      * for more details.
1990      *
1991      * Otherwise, the filename argument is mapped to a native library image in
1992      * an implementation-dependent manner.
1993      *
1994      * <p>
1995      * The call {@code System.load(name)} is effectively equivalent
1996      * to the call:
1997      * <blockquote><pre>
1998      * Runtime.getRuntime().load(name)
1999      * </pre></blockquote>
2000      *
2001      * @param      filename   the file to load.
2002      * @throws     SecurityException  if a security manager exists and its
2003      *             {@code checkLink} method doesn't allow
2004      *             loading of the specified dynamic library
2005      * @throws     UnsatisfiedLinkError  if either the filename is not an
2006      *             absolute path name, the native library is not statically
2007      *             linked with the VM, or the library cannot be mapped to
2008      *             a native library image by the host system.
2009      * @throws     NullPointerException if {@code filename} is {@code null}
2010      * @see        java.lang.Runtime#load(java.lang.String)
2011      * @see        java.lang.SecurityManager#checkLink(java.lang.String)
2012      */
2013     @CallerSensitive
2014     public static void load(String filename) {
2015         Runtime.getRuntime().load0(Reflection.getCallerClass(), filename);
2016     }
2017 
2018     /**
2019      * Loads the native library specified by the {@code libname}
2020      * argument.  The {@code libname} argument must not contain any platform
2021      * specific prefix, file extension or path. If a native library
2022      * called {@code libname} is statically linked with the VM, then the
2023      * JNI_OnLoad_{@code libname} function exported by the library is invoked.
2024      * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
2025      * for more details.
2026      *
2027      * Otherwise, the libname argument is loaded from a system library
2028      * location and mapped to a native library image in an
2029      * implementation-dependent manner.
2030      * <p>
2031      * The call {@code System.loadLibrary(name)} is effectively
2032      * equivalent to the call
2033      * <blockquote><pre>
2034      * Runtime.getRuntime().loadLibrary(name)
2035      * </pre></blockquote>
2036      *
2037      * @param      libname   the name of the library.
2038      * @throws     SecurityException  if a security manager exists and its
2039      *             {@code checkLink} method doesn't allow
2040      *             loading of the specified dynamic library
2041      * @throws     UnsatisfiedLinkError if either the libname argument
2042      *             contains a file path, the native library is not statically
2043      *             linked with the VM,  or the library cannot be mapped to a
2044      *             native library image by the host system.
2045      * @throws     NullPointerException if {@code libname} is {@code null}
2046      * @see        java.lang.Runtime#loadLibrary(java.lang.String)
2047      * @see        java.lang.SecurityManager#checkLink(java.lang.String)
2048      */
2049     @CallerSensitive
2050     public static void loadLibrary(String libname) {
2051         Runtime.getRuntime().loadLibrary0(Reflection.getCallerClass(), libname);
2052     }
2053 
2054     /**
2055      * Maps a library name into a platform-specific string representing
2056      * a native library.
2057      *
2058      * @param      libname the name of the library.
2059      * @return     a platform-dependent native library name.
2060      * @throws     NullPointerException if {@code libname} is {@code null}
2061      * @see        java.lang.System#loadLibrary(java.lang.String)
2062      * @see        java.lang.ClassLoader#findLibrary(java.lang.String)
2063      * @since      1.2
2064      */
2065     public static native String mapLibraryName(String libname);
2066 
2067     /**
2068      * Create PrintStream for stdout/err based on encoding.
2069      */
2070     private static PrintStream newPrintStream(OutputStream out, String enc) {
2071         if (enc != null) {
2072             return new PrintStream(new BufferedOutputStream(out, 128), true,
2073                                    Charset.forName(enc, UTF_8.INSTANCE));
2074         }
2075         return new PrintStream(new BufferedOutputStream(out, 128), true);
2076     }
2077 
2078     /**
2079      * Logs an exception/error at initialization time to stdout or stderr.
2080      *
2081      * @param printToStderr to print to stderr rather than stdout
2082      * @param printStackTrace to print the stack trace
2083      * @param msg the message to print before the exception, can be {@code null}
2084      * @param e the exception or error
2085      */
2086     private static void logInitException(boolean printToStderr,
2087                                          boolean printStackTrace,
2088                                          String msg,
2089                                          Throwable e) {
2090         if (VM.initLevel() < 1) {
2091             throw new InternalError("system classes not initialized");
2092         }
2093         PrintStream log = (printToStderr) ? err : out;
2094         if (msg != null) {
2095             log.println(msg);
2096         }
2097         if (printStackTrace) {
2098             e.printStackTrace(log);
2099         } else {
2100             log.println(e);
2101             for (Throwable suppressed : e.getSuppressed()) {
2102                 log.println("Suppressed: " + suppressed);
2103             }
2104             Throwable cause = e.getCause();
2105             if (cause != null) {
2106                 log.println("Caused by: " + cause);
2107             }
2108         }
2109     }
2110 
2111     /**
2112      * Create the Properties object from a map - masking out system properties
2113      * that are not intended for public access.
2114      */
2115     private static Properties createProperties(Map<String, String> initialProps) {
2116         Properties properties = new Properties(initialProps.size());
2117         for (var entry : initialProps.entrySet()) {
2118             String prop = entry.getKey();
2119             switch (prop) {
2120                 // Do not add private system properties to the Properties
2121                 case "sun.nio.MaxDirectMemorySize":
2122                 case "sun.nio.PageAlignDirectMemory":
2123                     // used by java.lang.Integer.IntegerCache
2124                 case "java.lang.Integer.IntegerCache.high":
2125                     // used by sun.launcher.LauncherHelper
2126                 case "sun.java.launcher.diag":
2127                     // used by jdk.internal.loader.ClassLoaders
2128                 case "jdk.boot.class.path.append":
2129                     break;
2130                 default:
2131                     properties.put(prop, entry.getValue());
2132             }
2133         }
2134         return properties;
2135     }
2136 
2137     /**
2138      * Initialize the system class.  Called after thread initialization.
2139      */
2140     private static void initPhase1() {
2141 
2142         // register the shared secrets - do this first, since SystemProps.initProperties
2143         // might initialize CharsetDecoders that rely on it
2144         setJavaLangAccess();
2145 
2146         // VM might invoke JNU_NewStringPlatform() to set those encoding
2147         // sensitive properties (user.home, user.name, boot.class.path, etc.)
2148         // during "props" initialization.
2149         // The charset is initialized in System.c and does not depend on the Properties.
2150         Map<String, String> tempProps = SystemProps.initProperties();
2151         VersionProps.init(tempProps);
2152 
2153         // There are certain system configurations that may be controlled by
2154         // VM options such as the maximum amount of direct memory and
2155         // Integer cache size used to support the object identity semantics
2156         // of autoboxing.  Typically, the library will obtain these values
2157         // from the properties set by the VM.  If the properties are for
2158         // internal implementation use only, these properties should be
2159         // masked from the system properties.
2160         //
2161         // Save a private copy of the system properties object that
2162         // can only be accessed by the internal implementation.
2163         VM.saveProperties(tempProps);
2164         props = createProperties(tempProps);
2165 
2166         // Check if sun.jnu.encoding is supported. If not, replace it with UTF-8.
2167         var jnuEncoding = props.getProperty("sun.jnu.encoding");
2168         if (jnuEncoding == null || !Charset.isSupported(jnuEncoding)) {
2169             notSupportedJnuEncoding = jnuEncoding == null ? "null" : jnuEncoding;
2170             props.setProperty("sun.jnu.encoding", "UTF-8");
2171         }
2172 
2173         StaticProperty.javaHome();          // Load StaticProperty to cache the property values
2174 
2175         lineSeparator = props.getProperty("line.separator");
2176 
2177         FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
2178         FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
2179         FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
2180         initialIn = new BufferedInputStream(fdIn);
2181         setIn0(initialIn);
2182         // stdout/err.encoding are set when the VM is associated with the terminal,
2183         // thus they are equivalent to Console.charset(), otherwise the encodings
2184         // of those properties default to native.encoding
2185         setOut0(newPrintStream(fdOut, props.getProperty("stdout.encoding")));
2186         setErr0(newPrintStream(fdErr, props.getProperty("stderr.encoding")));
2187 
2188         // Setup Java signal handlers for HUP, TERM, and INT (where available).
2189         Terminator.setup();
2190 
2191         // Initialize any miscellaneous operating system settings that need to be
2192         // set for the class libraries. Currently this is no-op everywhere except
2193         // for Windows where the process-wide error mode is set before the java.io
2194         // classes are used.
2195         VM.initializeOSEnvironment();
2196 
2197         // start Finalizer and Reference Handler threads
2198         SharedSecrets.getJavaLangRefAccess().startThreads();
2199 
2200         // system properties, java.lang and other core classes are now initialized
2201         VM.initLevel(1);
2202     }
2203 
2204     // @see #initPhase2()
2205     static ModuleLayer bootLayer;
2206 
2207     /*
2208      * Invoked by VM.  Phase 2 module system initialization.
2209      * Only classes in java.base can be loaded in this phase.
2210      *
2211      * @param printToStderr print exceptions to stderr rather than stdout
2212      * @param printStackTrace print stack trace when exception occurs
2213      *
2214      * @return JNI_OK for success, JNI_ERR for failure
2215      */
2216     private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
2217 
2218         try {
2219             bootLayer = ModuleBootstrap.boot();
2220         } catch (Exception | Error e) {
2221             logInitException(printToStderr, printStackTrace,
2222                              "Error occurred during initialization of boot layer", e);
2223             return -1; // JNI_ERR
2224         }
2225 
2226         // module system initialized
2227         VM.initLevel(2);
2228 
2229         return 0; // JNI_OK
2230     }
2231 
2232     /*
2233      * Invoked by VM.  Phase 3 is the final system initialization:
2234      * 1. eagerly initialize bootstrap method factories that might interact
2235      *    negatively with custom security managers and custom class loaders
2236      * 2. set security manager
2237      * 3. set system class loader
2238      * 4. set TCCL
2239      *
2240      * This method must be called after the module system initialization.
2241      * The security manager and system class loader may be a custom class from
2242      * the application classpath or modulepath.
2243      */
2244     @SuppressWarnings("removal")
2245     private static void initPhase3() {
2246 
2247         // Initialize the StringConcatFactory eagerly to avoid potential
2248         // bootstrap circularity issues that could be caused by a custom
2249         // SecurityManager
2250         Unsafe.getUnsafe().ensureClassInitialized(StringConcatFactory.class);
2251 
2252         // Emit a warning if java.io.tmpdir is set via the command line
2253         // to a directory that doesn't exist
2254         if (SystemProps.isBadIoTmpdir()) {
2255             System.err.println("WARNING: java.io.tmpdir directory does not exist");
2256         }
2257 
2258         String smProp = System.getProperty("java.security.manager");
2259         boolean needWarning = false;
2260         if (smProp != null) {
2261             switch (smProp) {
2262                 case "disallow":
2263                     allowSecurityManager = NEVER;
2264                     break;
2265                 case "allow":
2266                     allowSecurityManager = MAYBE;
2267                     break;
2268                 case "":
2269                 case "default":
2270                     implSetSecurityManager(new SecurityManager());
2271                     allowSecurityManager = MAYBE;
2272                     needWarning = true;
2273                     break;
2274                 default:
2275                     try {
2276                         ClassLoader cl = ClassLoader.getBuiltinAppClassLoader();
2277                         Class<?> c = Class.forName(smProp, false, cl);
2278                         Constructor<?> ctor = c.getConstructor();
2279                         // Must be a public subclass of SecurityManager with
2280                         // a public no-arg constructor
2281                         if (!SecurityManager.class.isAssignableFrom(c) ||
2282                             !Modifier.isPublic(c.getModifiers()) ||
2283                             !Modifier.isPublic(ctor.getModifiers())) {
2284                             throw new Error("Could not create SecurityManager: "
2285                                              + ctor.toString());
2286                         }
2287                         // custom security manager may be in non-exported package
2288                         ctor.setAccessible(true);
2289                         SecurityManager sm = (SecurityManager) ctor.newInstance();
2290                         implSetSecurityManager(sm);
2291                         needWarning = true;
2292                     } catch (Exception e) {
2293                         throw new InternalError("Could not create SecurityManager", e);
2294                     }
2295                     allowSecurityManager = MAYBE;
2296             }
2297         } else {
2298             allowSecurityManager = NEVER;
2299         }
2300 
2301         if (needWarning) {
2302             System.err.println("""
2303                     WARNING: A command line option has enabled the Security Manager
2304                     WARNING: The Security Manager is deprecated and will be removed in a future release""");
2305         }
2306 
2307         // Emit a warning if `sun.jnu.encoding` is not supported.
2308         if (notSupportedJnuEncoding != null) {
2309             System.err.println(
2310                     "WARNING: The encoding of the underlying platform's" +
2311                     " file system is not supported: " +
2312                     notSupportedJnuEncoding);
2313         }
2314 
2315         initialErrStream = System.err;
2316 
2317         // initializing the system class loader
2318         VM.initLevel(3);
2319 
2320         // system class loader initialized
2321         ClassLoader scl = ClassLoader.initSystemClassLoader();
2322 
2323         // set TCCL
2324         Thread.currentThread().setContextClassLoader(scl);
2325 
2326         // system is fully initialized
2327         VM.initLevel(4);
2328     }
2329 
2330     private static void setJavaLangAccess() {
2331         // Allow privileged classes outside of java.lang
2332         SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2333             public List<Method> getDeclaredPublicMethods(Class<?> klass, String name, Class<?>... parameterTypes) {
2334                 return klass.getDeclaredPublicMethods(name, parameterTypes);
2335             }
2336             public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2337                 return klass.getConstantPool();
2338             }
2339             public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2340                 return klass.casAnnotationType(oldType, newType);
2341             }
2342             public AnnotationType getAnnotationType(Class<?> klass) {
2343                 return klass.getAnnotationType();
2344             }
2345             public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2346                 return klass.getDeclaredAnnotationMap();
2347             }
2348             public byte[] getRawClassAnnotations(Class<?> klass) {
2349                 return klass.getRawAnnotations();
2350             }
2351             public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2352                 return klass.getRawTypeAnnotations();
2353             }
2354             public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2355                 return Class.getExecutableTypeAnnotationBytes(executable);
2356             }
2357             public <E extends Enum<E>>
2358             E[] getEnumConstantsShared(Class<E> klass) {
2359                 return klass.getEnumConstantsShared();
2360             }
2361             public void blockedOn(Interruptible b) {
2362                 Thread.blockedOn(b);
2363             }
2364             public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2365                 Shutdown.add(slot, registerShutdownInProgress, hook);
2366             }
2367             public Thread newThreadWithAcc(Runnable target, @SuppressWarnings("removal") AccessControlContext acc) {
2368                 return new Thread(target, acc);
2369             }
2370             @SuppressWarnings("removal")
2371             public void invokeFinalize(Object o) throws Throwable {
2372                 o.finalize();
2373             }
2374             public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2375                 return cl.createOrGetClassLoaderValueMap();
2376             }
2377             public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2378                 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2379             }
2380             public Class<?> defineClass(ClassLoader loader, Class<?> lookup, String name, byte[] b, ProtectionDomain pd,
2381                                         boolean initialize, int flags, Object classData) {
2382                 return ClassLoader.defineClass0(loader, lookup, name, b, 0, b.length, pd, initialize, flags, classData);
2383             }
2384             public Class<?> findBootstrapClassOrNull(String name) {
2385                 return ClassLoader.findBootstrapClassOrNull(name);
2386             }
2387             public Package definePackage(ClassLoader cl, String name, Module module) {
2388                 return cl.definePackage(name, module);
2389             }
2390             public String fastUUID(long lsb, long msb) {
2391                 return Long.fastUUID(lsb, msb);
2392             }
2393             @SuppressWarnings("removal")
2394             public void addNonExportedPackages(ModuleLayer layer) {
2395                 SecurityManager.addNonExportedPackages(layer);
2396             }
2397             @SuppressWarnings("removal")
2398             public void invalidatePackageAccessCache() {
2399                 SecurityManager.invalidatePackageAccessCache();
2400             }
2401             public Module defineModule(ClassLoader loader,
2402                                        ModuleDescriptor descriptor,
2403                                        URI uri) {
2404                 return new Module(null, loader, descriptor, uri);
2405             }
2406             public Module defineUnnamedModule(ClassLoader loader) {
2407                 return new Module(loader);
2408             }
2409             public void addReads(Module m1, Module m2) {
2410                 m1.implAddReads(m2);
2411             }
2412             public void addReadsAllUnnamed(Module m) {
2413                 m.implAddReadsAllUnnamed();
2414             }
2415             public void addExports(Module m, String pn) {
2416                 m.implAddExports(pn);
2417             }
2418             public void addExports(Module m, String pn, Module other) {
2419                 m.implAddExports(pn, other);
2420             }
2421             public void addExportsToAllUnnamed(Module m, String pn) {
2422                 m.implAddExportsToAllUnnamed(pn);
2423             }
2424             public void addOpens(Module m, String pn, Module other) {
2425                 m.implAddOpens(pn, other);
2426             }
2427             public void addOpensToAllUnnamed(Module m, String pn) {
2428                 m.implAddOpensToAllUnnamed(pn);
2429             }
2430             public void addOpensToAllUnnamed(Module m, Set<String> concealedPackages, Set<String> exportedPackages) {
2431                 m.implAddOpensToAllUnnamed(concealedPackages, exportedPackages);
2432             }
2433             public void addUses(Module m, Class<?> service) {
2434                 m.implAddUses(service);
2435             }
2436             public boolean isReflectivelyExported(Module m, String pn, Module other) {
2437                 return m.isReflectivelyExported(pn, other);
2438             }
2439             public boolean isReflectivelyOpened(Module m, String pn, Module other) {
2440                 return m.isReflectivelyOpened(pn, other);
2441             }
2442             public Module addEnableNativeAccess(Module m) {
2443                 return m.implAddEnableNativeAccess();
2444             }
2445             public void addEnableNativeAccessToAllUnnamed() {
2446                 Module.implAddEnableNativeAccessToAllUnnamed();
2447             }
2448             public void ensureNativeAccess(Module m, Class<?> owner, String methodName) {
2449                 m.ensureNativeAccess(owner, methodName);
2450             }
2451             public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2452                 return layer.getServicesCatalog();
2453             }
2454             public void bindToLoader(ModuleLayer layer, ClassLoader loader) {
2455                 layer.bindToLoader(loader);
2456             }
2457             public Stream<ModuleLayer> layers(ModuleLayer layer) {
2458                 return layer.layers();
2459             }
2460             public Stream<ModuleLayer> layers(ClassLoader loader) {
2461                 return ModuleLayer.layers(loader);
2462             }
2463 
2464             public String newStringNoRepl(byte[] bytes, Charset cs) throws CharacterCodingException  {
2465                 return String.newStringNoRepl(bytes, cs);
2466             }
2467 
2468             public byte[] getBytesNoRepl(String s, Charset cs) throws CharacterCodingException {
2469                 return String.getBytesNoRepl(s, cs);
2470             }
2471 
2472             public String newStringUTF8NoRepl(byte[] bytes, int off, int len) {
2473                 return String.newStringUTF8NoRepl(bytes, off, len);
2474             }
2475 
2476             public byte[] getBytesUTF8NoRepl(String s) {
2477                 return String.getBytesUTF8NoRepl(s);
2478             }
2479 
2480             public void inflateBytesToChars(byte[] src, int srcOff, char[] dst, int dstOff, int len) {
2481                 StringLatin1.inflate(src, srcOff, dst, dstOff, len);
2482             }
2483 
2484             public int decodeASCII(byte[] src, int srcOff, char[] dst, int dstOff, int len) {
2485                 return String.decodeASCII(src, srcOff, dst, dstOff, len);
2486             }
2487 
2488             public int encodeASCII(char[] src, int srcOff, byte[] dst, int dstOff, int len) {
2489                 return StringCoding.implEncodeAsciiArray(src, srcOff, dst, dstOff, len);
2490             }
2491 
2492             public InputStream initialSystemIn() {
2493                 return initialIn;
2494             }
2495 
2496             public void setCause(Throwable t, Throwable cause) {
2497                 t.setCause(cause);
2498             }
2499 
2500             public ProtectionDomain protectionDomain(Class<?> c) {
2501                 return c.protectionDomain();
2502             }
2503 
2504             public MethodHandle stringConcatHelper(String name, MethodType methodType) {
2505                 return StringConcatHelper.lookupStatic(name, methodType);
2506             }
2507 
2508             public long stringConcatInitialCoder() {
2509                 return StringConcatHelper.initialCoder();
2510             }
2511 
2512             public long stringConcatMix(long lengthCoder, String constant) {
2513                 return StringConcatHelper.mix(lengthCoder, constant);
2514             }
2515 
2516             public String join(String prefix, String suffix, String delimiter, String[] elements, int size) {
2517                 return String.join(prefix, suffix, delimiter, elements, size);
2518             }
2519 
2520             public Object classData(Class<?> c) {
2521                 return c.getClassData();
2522             }
2523 
2524             @Override
2525             public long findNative(ClassLoader loader, String entry) {
2526                 return ClassLoader.findNative(loader, entry);
2527             }
2528 
2529             @Override
2530             public void exit(int statusCode) {
2531                 Shutdown.exit(statusCode);
2532             }
2533 
2534             public Thread[] getAllThreads() {
2535                 return Thread.getAllThreads();
2536             }
2537 
2538             public ThreadContainer threadContainer(Thread thread) {
2539                 return thread.threadContainer();
2540             }
2541 
2542             public void start(Thread thread, ThreadContainer container) {
2543                 thread.start(container);
2544             }
2545 
2546             public StackableScope headStackableScope(Thread thread) {
2547                 return thread.headStackableScopes();
2548             }
2549 
2550             public void setHeadStackableScope(StackableScope scope) {
2551                 Thread.setHeadStackableScope(scope);
2552             }
2553 
2554             public Thread currentCarrierThread() {
2555                 return Thread.currentCarrierThread();
2556             }
2557 
2558             @ChangesCurrentThread
2559             public <V> V executeOnCarrierThread(Callable<V> task) throws Exception {
2560                 Thread thread = Thread.currentThread();
2561                 if (thread.isVirtual()) {
2562                     Thread carrier = Thread.currentCarrierThread();
2563                     carrier.setCurrentThread(carrier);
2564                     try {
2565                         return task.call();
2566                     } finally {
2567                         carrier.setCurrentThread(thread);
2568                     }
2569                 } else {
2570                     return task.call();
2571                 }
2572             }
2573 
2574             public <T> T getCarrierThreadLocal(CarrierThreadLocal<T> local) {
2575                 return ((ThreadLocal<T>)local).getCarrierThreadLocal();
2576             }
2577 
2578             public <T> void setCarrierThreadLocal(CarrierThreadLocal<T> local, T value) {
2579                 ((ThreadLocal<T>)local).setCarrierThreadLocal(value);
2580             }
2581 
2582             public void removeCarrierThreadLocal(CarrierThreadLocal<?> local) {
2583                 ((ThreadLocal<?>)local).removeCarrierThreadLocal();
2584             }
2585 
2586             public boolean isCarrierThreadLocalPresent(CarrierThreadLocal<?> local) {
2587                 return ((ThreadLocal<?>)local).isCarrierThreadLocalPresent();
2588             }
2589 
2590             public Object[] scopedValueCache() {
2591                 return Thread.scopedValueCache();
2592             }
2593 
2594             public void setScopedValueCache(Object[] cache) {
2595                 Thread.setScopedValueCache(cache);
2596             }
2597 
2598             public Object scopedValueBindings() {
2599                 return Thread.scopedValueBindings();
2600             }
2601 
2602             public Object findScopedValueBindings() {
2603                 return Thread.findScopedValueBindings();
2604             }
2605 
2606             public void setScopedValueBindings(Object bindings) {
2607                 Thread.setScopedValueBindings(bindings);
2608             }
2609 
2610             @ForceInline
2611             public void ensureMaterializedForStackWalk(Object value) {
2612                 Thread.ensureMaterializedForStackWalk(value);
2613             }
2614 
2615             public Continuation getContinuation(Thread thread) {
2616                 return thread.getContinuation();
2617             }
2618 
2619             public void setContinuation(Thread thread, Continuation continuation) {
2620                 thread.setContinuation(continuation);
2621             }
2622 
2623             public ContinuationScope virtualThreadContinuationScope() {
2624                 return VirtualThread.continuationScope();
2625             }
2626 
2627             public void parkVirtualThread() {
2628                 Thread thread = Thread.currentThread();
2629                 if (thread instanceof BaseVirtualThread vthread) {
2630                     vthread.park();
2631                 } else {
2632                     throw new WrongThreadException();
2633                 }
2634             }
2635 
2636             public void parkVirtualThread(long nanos) {
2637                 Thread thread = Thread.currentThread();
2638                 if (thread instanceof BaseVirtualThread vthread) {
2639                     vthread.parkNanos(nanos);
2640                 } else {
2641                     throw new WrongThreadException();
2642                 }
2643             }
2644 
2645             public void unparkVirtualThread(Thread thread) {
2646                 if (thread instanceof BaseVirtualThread vthread) {
2647                     vthread.unpark();
2648                 } else {
2649                     throw new WrongThreadException();
2650                 }
2651             }
2652 
2653             public StackWalker newStackWalkerInstance(Set<StackWalker.Option> options,
2654                                                       ContinuationScope contScope,
2655                                                       Continuation continuation) {
2656                 return StackWalker.newInstance(options, null, contScope, continuation);
2657             }
2658 
2659             @Override
2660             public Class<?> asPrimaryType(Class<?> clazz) {
2661                 return clazz.asPrimaryType();
2662             }
2663             public Class<?> asValueType(Class<?> clazz) {
2664                 return clazz.asValueType();
2665             }
2666 
2667             public boolean isPrimaryType(Class<?> clazz) {
2668                 return clazz.isPrimaryType();
2669             }
2670             public boolean isPrimitiveValueType(Class<?> clazz) {
2671                 return clazz.isPrimitiveValueType();
2672             }
2673             public boolean isPrimitiveClass(Class<?> clazz) {
2674                 return clazz.isPrimitiveClass();
2675             }
2676         });
2677     }
2678 }