1 /*
2 * Copyright (c) 1994, 2024, 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.foreign.MemorySegment;
39 import java.lang.invoke.MethodHandle;
40 import java.lang.invoke.MethodType;
41 import java.lang.module.ModuleDescriptor;
42 import java.lang.reflect.Executable;
43 import java.lang.reflect.Method;
44 import java.net.URI;
45 import java.net.URL;
46 import java.nio.channels.Channel;
47 import java.nio.channels.spi.SelectorProvider;
48 import java.nio.charset.CharacterCodingException;
49 import java.nio.charset.Charset;
50 import java.security.AccessController;
51 import java.security.CodeSource;
52 import java.security.PrivilegedAction;
53 import java.security.ProtectionDomain;
54 import java.util.Collections;
55 import java.util.List;
56 import java.util.Locale;
57 import java.util.Map;
58 import java.util.Objects;
59 import java.util.Properties;
60 import java.util.PropertyPermission;
61 import java.util.ResourceBundle;
62 import java.util.Set;
63 import java.util.WeakHashMap;
64 import java.util.concurrent.Executor;
65 import java.util.concurrent.ScheduledExecutorService;
66 import java.util.function.Supplier;
67 import java.util.concurrent.ConcurrentHashMap;
68 import java.util.stream.Stream;
69
70 import jdk.internal.javac.Restricted;
71 import jdk.internal.loader.NativeLibraries;
72 import jdk.internal.logger.LoggerFinderLoader.TemporaryLoggerFinder;
73 import jdk.internal.misc.Blocker;
74 import jdk.internal.misc.CarrierThreadLocal;
75 import jdk.internal.util.StaticProperty;
76 import jdk.internal.module.ModuleBootstrap;
77 import jdk.internal.module.ServicesCatalog;
78 import jdk.internal.reflect.CallerSensitive;
79 import jdk.internal.reflect.Reflection;
80 import jdk.internal.access.JavaLangAccess;
81 import jdk.internal.access.SharedSecrets;
82 import jdk.internal.logger.LoggerFinderLoader;
83 import jdk.internal.logger.LazyLoggers;
84 import jdk.internal.logger.LocalizedLoggerWrapper;
85 import jdk.internal.misc.VM;
86 import jdk.internal.util.SystemProps;
87 import jdk.internal.vm.Continuation;
88 import jdk.internal.vm.ContinuationScope;
89 import jdk.internal.vm.StackableScope;
90 import jdk.internal.vm.ThreadContainer;
91 import jdk.internal.vm.annotation.IntrinsicCandidate;
92 import jdk.internal.vm.annotation.Stable;
93 import sun.reflect.annotation.AnnotationType;
94 import sun.nio.ch.Interruptible;
95 import sun.nio.cs.UTF_8;
96 import sun.security.util.SecurityConstants;
97
98 /**
99 * The {@code System} class contains several useful class fields
100 * and methods. It cannot be instantiated.
101 *
102 * Among the facilities provided by the {@code System} class
103 * are standard input, standard output, and error output streams;
104 * access to externally defined properties and environment
105 * variables; a means of loading files and libraries; and a utility
106 * method for quickly copying a portion of an array.
107 *
108 * @since 1.0
109 */
110 public final class System {
111 /* Register the natives via the static initializer.
112 *
113 * The VM will invoke the initPhase1 method to complete the initialization
114 * of this class separate from <clinit>.
115 */
116 private static native void registerNatives();
117 static {
118 registerNatives();
119 }
120
121 /** Don't let anyone instantiate this class */
122 private System() {
123 }
124
125 /**
126 * The "standard" input stream. This stream is already
127 * open and ready to supply input data. Typically this stream
128 * corresponds to keyboard input or another input source specified by
129 * the host environment or user. In case this stream is wrapped
130 * in a {@link java.io.InputStreamReader}, {@link Console#charset()}
131 * should be used for the charset, or consider using
132 * {@link Console#reader()}.
133 *
134 * @see Console#charset()
135 * @see Console#reader()
136 */
137 public static final InputStream in = null;
138
139 /**
140 * The "standard" output stream. This stream is already
141 * open and ready to accept output data. Typically this stream
142 * corresponds to display output or another output destination
143 * specified by the host environment or user. The encoding used
144 * in the conversion from characters to bytes is equivalent to
145 * {@link ##stdout.encoding stdout.encoding}.
146 * <p>
147 * For simple stand-alone Java applications, a typical way to write
148 * a line of output data is:
149 * <blockquote><pre>
150 * System.out.println(data)
151 * </pre></blockquote>
152 * <p>
153 * See the {@code println} methods in class {@code PrintStream}.
154 *
155 * @see java.io.PrintStream#println()
156 * @see java.io.PrintStream#println(boolean)
157 * @see java.io.PrintStream#println(char)
158 * @see java.io.PrintStream#println(char[])
159 * @see java.io.PrintStream#println(double)
160 * @see java.io.PrintStream#println(float)
161 * @see java.io.PrintStream#println(int)
162 * @see java.io.PrintStream#println(long)
163 * @see java.io.PrintStream#println(java.lang.Object)
164 * @see java.io.PrintStream#println(java.lang.String)
165 * @see ##stdout.encoding stdout.encoding
166 */
167 public static final PrintStream out = null;
168
169 /**
170 * The "standard" error output stream. This stream is already
171 * open and ready to accept output data.
172 * <p>
173 * Typically this stream corresponds to display output or another
174 * output destination specified by the host environment or user. By
175 * convention, this output stream is used to display error messages
176 * or other information that should come to the immediate attention
177 * of a user even if the principal output stream, the value of the
178 * variable {@code out}, has been redirected to a file or other
179 * destination that is typically not continuously monitored.
180 * The encoding used in the conversion from characters to bytes is
181 * equivalent to {@link ##stderr.encoding stderr.encoding}.
182 *
183 * @see ##stderr.encoding stderr.encoding
184 */
185 public static final PrintStream err = null;
186
187 // Initial values of System.in and System.err, set in initPhase1().
188 private static @Stable InputStream initialIn;
189 private static @Stable PrintStream initialErr;
190
191 // `sun.jnu.encoding` if it is not supported. Otherwise null.
192 // It is initialized in `initPhase1()` before any charset providers
193 // are initialized.
194 private static String notSupportedJnuEncoding;
195
196 /**
197 * Reassigns the "standard" input stream.
198 *
199 * @param in the new standard input stream.
200 *
201 * @since 1.1
202 */
203 public static void setIn(InputStream in) {
204 checkIO();
205 setIn0(in);
206 }
207
208 /**
209 * Reassigns the "standard" output stream.
210 *
211 * @param out the new standard output stream
212 *
213 * @since 1.1
214 */
215 public static void setOut(PrintStream out) {
216 checkIO();
217 setOut0(out);
218 }
219
220 /**
221 * Reassigns the "standard" error output stream.
222 *
223 * @param err the new standard error output stream.
224 *
225 * @since 1.1
226 */
227 public static void setErr(PrintStream err) {
228 checkIO();
229 setErr0(err);
230 }
231
232 private static volatile Console cons;
233
234 /**
235 * Returns the unique {@link java.io.Console Console} object associated
236 * with the current Java virtual machine, if any.
237 *
238 * @return The system console, if any, otherwise {@code null}.
239 *
240 * @since 1.6
241 */
242 public static Console console() {
243 Console c;
244 if ((c = cons) == null) {
245 synchronized (System.class) {
246 if ((c = cons) == null) {
247 cons = c = SharedSecrets.getJavaIOAccess().console();
248 }
249 }
250 }
251 return c;
252 }
253
254 /**
255 * Returns the channel inherited from the entity that created this
256 * Java virtual machine.
257 *
258 * This method returns the channel obtained by invoking the
259 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
260 * inheritedChannel} method of the system-wide default
261 * {@link java.nio.channels.spi.SelectorProvider} object.
262 *
263 * <p> In addition to the network-oriented channels described in
264 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
265 * inheritedChannel}, this method may return other kinds of
266 * channels in the future.
267 *
268 * @return The inherited channel, if any, otherwise {@code null}.
269 *
270 * @throws IOException
271 * If an I/O error occurs
272 *
273 * @since 1.5
274 */
275 public static Channel inheritedChannel() throws IOException {
276 return SelectorProvider.provider().inheritedChannel();
277 }
278
279 private static void checkIO() {
280 @SuppressWarnings("removal")
281 SecurityManager sm = getSecurityManager();
282 if (sm != null) {
283 sm.checkPermission(new RuntimePermission("setIO"));
284 }
285 }
286
287 private static native void setIn0(InputStream in);
288 private static native void setOut0(PrintStream out);
289 private static native void setErr0(PrintStream err);
290
291 private static class CallersHolder {
292 // Remember callers of setSecurityManager() here so that warning
293 // is only printed once for each different caller
294 static final Map<Class<?>, Boolean> callers
295 = Collections.synchronizedMap(new WeakHashMap<>());
296 }
297
298 static URL codeSource(Class<?> clazz) {
299 PrivilegedAction<ProtectionDomain> pa = clazz::getProtectionDomain;
300 @SuppressWarnings("removal")
301 CodeSource cs = AccessController.doPrivileged(pa).getCodeSource();
302 return (cs != null) ? cs.getLocation() : null;
303 }
304
305 /**
306 * Throws {@code UnsupportedOperationException}. Setting a security manager
307 * is not supported.
308 *
309 * @param sm ignored
310 * @throws UnsupportedOperationException always
311 * @see #getSecurityManager
312 * @deprecated This method originally set
313 * {@linkplain SecurityManager the system-wide Security Manager}.
314 * Setting a Security Manager is no longer supported. There is no
315 * replacement for the Security Manager or this method.
316 */
317 @Deprecated(since="17", forRemoval=true)
318 public static void setSecurityManager(@SuppressWarnings("removal") SecurityManager sm) {
319 throw new UnsupportedOperationException(
320 "Setting a Security Manager is not supported");
321 }
322
323 /**
324 * Returns {@code null}. Setting a security manager is not supported.
325 *
326 * @return {@code null}
327 * @see #setSecurityManager
328 * @deprecated This method originally returned
329 * {@linkplain SecurityManager the system-wide Security Manager}.
330 * Setting a Security Manager is no longer supported. There is no
331 * replacement for the Security Manager or this method.
332 */
333 @SuppressWarnings("removal")
334 @Deprecated(since="17", forRemoval=true)
335 public static SecurityManager getSecurityManager() {
336 return null;
337 }
338
339 /**
340 * Returns the current time in milliseconds. Note that
341 * while the unit of time of the return value is a millisecond,
342 * the granularity of the value depends on the underlying
343 * operating system and may be larger. For example, many
344 * operating systems measure time in units of tens of
345 * milliseconds.
346 *
347 * <p> See the description of the class {@code Date} for
348 * a discussion of slight discrepancies that may arise between
349 * "computer time" and coordinated universal time (UTC).
350 *
351 * @return the difference, measured in milliseconds, between
352 * the current time and midnight, January 1, 1970 UTC.
353 * @see java.util.Date
354 */
355 @IntrinsicCandidate
356 public static native long currentTimeMillis();
357
358 /**
359 * Returns the current value of the running Java Virtual Machine's
360 * high-resolution time source, in nanoseconds.
361 *
362 * This method can only be used to measure elapsed time and is
363 * not related to any other notion of system or wall-clock time.
364 * The value returned represents nanoseconds since some fixed but
365 * arbitrary <i>origin</i> time (perhaps in the future, so values
366 * may be negative). The same origin is used by all invocations of
367 * this method in an instance of a Java virtual machine; other
368 * virtual machine instances are likely to use a different origin.
369 *
370 * <p>This method provides nanosecond precision, but not necessarily
371 * nanosecond resolution (that is, how frequently the value changes)
372 * - no guarantees are made except that the resolution is at least as
373 * good as that of {@link #currentTimeMillis()}.
374 *
375 * <p>Differences in successive calls that span greater than
376 * approximately 292 years (2<sup>63</sup> nanoseconds) will not
377 * correctly compute elapsed time due to numerical overflow.
378 *
379 * <p>The values returned by this method become meaningful only when
380 * the difference between two such values, obtained within the same
381 * instance of a Java virtual machine, is computed.
382 *
383 * <p>For example, to measure how long some code takes to execute:
384 * <pre> {@code
385 * long startTime = System.nanoTime();
386 * // ... the code being measured ...
387 * long elapsedNanos = System.nanoTime() - startTime;}</pre>
388 *
389 * <p>To compare elapsed time against a timeout, use <pre> {@code
390 * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
391 * instead of <pre> {@code
392 * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
393 * because of the possibility of numerical overflow.
394 *
395 * @return the current value of the running Java Virtual Machine's
396 * high-resolution time source, in nanoseconds
397 * @since 1.5
398 */
399 @IntrinsicCandidate
400 public static native long nanoTime();
401
402 /**
403 * Copies an array from the specified source array, beginning at the
404 * specified position, to the specified position of the destination array.
405 * A subsequence of array components are copied from the source
406 * array referenced by {@code src} to the destination array
407 * referenced by {@code dest}. The number of components copied is
408 * equal to the {@code length} argument. The components at
409 * positions {@code srcPos} through
410 * {@code srcPos+length-1} in the source array are copied into
411 * positions {@code destPos} through
412 * {@code destPos+length-1}, respectively, of the destination
413 * array.
414 * <p>
415 * If the {@code src} and {@code dest} arguments refer to the
416 * same array object, then the copying is performed as if the
417 * components at positions {@code srcPos} through
418 * {@code srcPos+length-1} were first copied to a temporary
419 * array with {@code length} components and then the contents of
420 * the temporary array were copied into positions
421 * {@code destPos} through {@code destPos+length-1} of the
422 * destination array.
423 * <p>
424 * If {@code dest} is {@code null}, then a
425 * {@code NullPointerException} is thrown.
426 * <p>
427 * If {@code src} is {@code null}, then a
428 * {@code NullPointerException} is thrown and the destination
429 * array is not modified.
430 * <p>
431 * Otherwise, if any of the following is true, an
432 * {@code ArrayStoreException} is thrown and the destination is
433 * not modified:
434 * <ul>
435 * <li>The {@code src} argument refers to an object that is not an
436 * array.
437 * <li>The {@code dest} argument refers to an object that is not an
438 * array.
439 * <li>The {@code src} argument and {@code dest} argument refer
440 * to arrays whose component types are different primitive types.
441 * <li>The {@code src} argument refers to an array with a primitive
442 * component type and the {@code dest} argument refers to an array
443 * with a reference component type.
444 * <li>The {@code src} argument refers to an array with a reference
445 * component type and the {@code dest} argument refers to an array
446 * with a primitive component type.
447 * </ul>
448 * <p>
449 * Otherwise, if any of the following is true, an
450 * {@code IndexOutOfBoundsException} is
451 * thrown and the destination is not modified:
452 * <ul>
453 * <li>The {@code srcPos} argument is negative.
454 * <li>The {@code destPos} argument is negative.
455 * <li>The {@code length} argument is negative.
456 * <li>{@code srcPos+length} is greater than
457 * {@code src.length}, the length of the source array.
458 * <li>{@code destPos+length} is greater than
459 * {@code dest.length}, the length of the destination array.
460 * </ul>
461 * <p>
462 * Otherwise, if any actual component of the source array from
463 * position {@code srcPos} through
464 * {@code srcPos+length-1} cannot be converted to the component
465 * type of the destination array by assignment conversion, an
466 * {@code ArrayStoreException} is thrown. In this case, let
467 * <b><i>k</i></b> be the smallest nonnegative integer less than
468 * length such that {@code src[srcPos+}<i>k</i>{@code ]}
469 * cannot be converted to the component type of the destination
470 * array; when the exception is thrown, source array components from
471 * positions {@code srcPos} through
472 * {@code srcPos+}<i>k</i>{@code -1}
473 * will already have been copied to destination array positions
474 * {@code destPos} through
475 * {@code destPos+}<i>k</I>{@code -1} and no other
476 * positions of the destination array will have been modified.
477 * (Because of the restrictions already itemized, this
478 * paragraph effectively applies only to the situation where both
479 * arrays have component types that are reference types.)
480 *
481 * @param src the source array.
482 * @param srcPos starting position in the source array.
483 * @param dest the destination array.
484 * @param destPos starting position in the destination data.
485 * @param length the number of array elements to be copied.
486 * @throws IndexOutOfBoundsException if copying would cause
487 * access of data outside array bounds.
488 * @throws ArrayStoreException if an element in the {@code src}
489 * array could not be stored into the {@code dest} array
490 * because of a type mismatch.
491 * @throws NullPointerException if either {@code src} or
492 * {@code dest} is {@code null}.
493 */
494 @IntrinsicCandidate
495 public static native void arraycopy(Object src, int srcPos,
496 Object dest, int destPos,
497 int length);
498
499 /**
500 * Returns the same hash code for the given object as
501 * would be returned by the default method hashCode(),
502 * whether or not the given object's class overrides
503 * hashCode().
504 * The hash code for the null reference is zero.
505 *
506 * @param x object for which the hashCode is to be calculated
507 * @return the hashCode
508 * @since 1.1
509 * @see Object#hashCode
510 * @see java.util.Objects#hashCode(Object)
511 */
512 @IntrinsicCandidate
513 public static native int identityHashCode(Object x);
514
515 /**
516 * System properties.
517 *
518 * See {@linkplain #getProperties getProperties} for details.
519 */
520 private static Properties props;
521
522 /**
523 * Determines the current system properties.
524 * <p>
525 * The current set of system properties for use by the
526 * {@link #getProperty(String)} method is returned as a
527 * {@code Properties} object. If there is no current set of
528 * system properties, a set of system properties is first created and
529 * initialized. This set of system properties includes a value
530 * for each of the following keys unless the description of the associated
531 * value indicates that the value is optional.
532 * <table class="striped" style="text-align:left">
533 * <caption style="display:none">Shows property keys and associated values</caption>
534 * <thead>
535 * <tr><th scope="col">Key</th>
536 * <th scope="col">Description of Associated Value</th></tr>
537 * </thead>
538 * <tbody>
539 * <tr><th scope="row">{@systemProperty java.version}</th>
540 * <td>Java Runtime Environment version, which may be interpreted
541 * as a {@link Runtime.Version}</td></tr>
542 * <tr><th scope="row">{@systemProperty java.version.date}</th>
543 * <td>Java Runtime Environment version date, in ISO-8601 YYYY-MM-DD
544 * format, which may be interpreted as a {@link
545 * java.time.LocalDate}</td></tr>
546 * <tr><th scope="row">{@systemProperty java.vendor}</th>
547 * <td>Java Runtime Environment vendor</td></tr>
548 * <tr><th scope="row">{@systemProperty java.vendor.url}</th>
549 * <td>Java vendor URL</td></tr>
550 * <tr><th scope="row">{@systemProperty java.vendor.version}</th>
551 * <td>Java vendor version <em>(optional)</em> </td></tr>
552 * <tr><th scope="row">{@systemProperty java.home}</th>
553 * <td>Java installation directory</td></tr>
554 * <tr><th scope="row">{@systemProperty java.vm.specification.version}</th>
555 * <td>Java Virtual Machine specification version, whose value is the
556 * {@linkplain Runtime.Version#feature feature} element of the
557 * {@linkplain Runtime#version() runtime version}</td></tr>
558 * <tr><th scope="row">{@systemProperty java.vm.specification.vendor}</th>
559 * <td>Java Virtual Machine specification vendor</td></tr>
560 * <tr><th scope="row">{@systemProperty java.vm.specification.name}</th>
561 * <td>Java Virtual Machine specification name</td></tr>
562 * <tr><th scope="row">{@systemProperty java.vm.version}</th>
563 * <td>Java Virtual Machine implementation version which may be
564 * interpreted as a {@link Runtime.Version}</td></tr>
565 * <tr><th scope="row">{@systemProperty java.vm.vendor}</th>
566 * <td>Java Virtual Machine implementation vendor</td></tr>
567 * <tr><th scope="row">{@systemProperty java.vm.name}</th>
568 * <td>Java Virtual Machine implementation name</td></tr>
569 * <tr><th scope="row">{@systemProperty java.specification.version}</th>
570 * <td>Java Runtime Environment specification version, whose value is
571 * the {@linkplain Runtime.Version#feature feature} element of the
572 * {@linkplain Runtime#version() runtime version}</td></tr>
573 * <tr><th scope="row">{@systemProperty java.specification.maintenance.version}</th>
574 * <td>Java Runtime Environment specification maintenance version,
575 * may be interpreted as a positive integer <em>(optional, see below)</em></td></tr>
576 * <tr><th scope="row">{@systemProperty java.specification.vendor}</th>
577 * <td>Java Runtime Environment specification vendor</td></tr>
578 * <tr><th scope="row">{@systemProperty java.specification.name}</th>
579 * <td>Java Runtime Environment specification name</td></tr>
580 * <tr><th scope="row">{@systemProperty java.class.version}</th>
581 * <td>{@linkplain java.lang.reflect.ClassFileFormatVersion#latest() Latest}
582 * Java class file format version recognized by the Java runtime as {@code "MAJOR.MINOR"}
583 * where {@link java.lang.reflect.ClassFileFormatVersion#major() MAJOR} and {@code MINOR}
584 * are both formatted as decimal integers</td></tr>
585 * <tr><th scope="row">{@systemProperty java.class.path}</th>
586 * <td>Java class path (refer to
587 * {@link ClassLoader#getSystemClassLoader()} for details)</td></tr>
588 * <tr><th scope="row">{@systemProperty java.library.path}</th>
589 * <td>List of paths to search when loading libraries</td></tr>
590 * <tr><th scope="row">{@systemProperty java.io.tmpdir}</th>
591 * <td>Default temp file path</td></tr>
592 * <tr><th scope="row">{@systemProperty os.name}</th>
593 * <td>Operating system name</td></tr>
594 * <tr><th scope="row">{@systemProperty os.arch}</th>
595 * <td>Operating system architecture</td></tr>
596 * <tr><th scope="row">{@systemProperty os.version}</th>
597 * <td>Operating system version</td></tr>
598 * <tr><th scope="row">{@systemProperty file.separator}</th>
599 * <td>File separator ("/" on UNIX)</td></tr>
600 * <tr><th scope="row">{@systemProperty path.separator}</th>
601 * <td>Path separator (":" on UNIX)</td></tr>
602 * <tr><th scope="row">{@systemProperty line.separator}</th>
603 * <td>Line separator ("\n" on UNIX)</td></tr>
604 * <tr><th scope="row">{@systemProperty user.name}</th>
605 * <td>User's account name</td></tr>
606 * <tr><th scope="row">{@systemProperty user.home}</th>
607 * <td>User's home directory</td></tr>
608 * <tr><th scope="row">{@systemProperty user.dir}</th>
609 * <td>User's current working directory</td></tr>
610 * <tr><th scope="row">{@systemProperty native.encoding}</th>
611 * <td>Character encoding name derived from the host environment and/or
612 * the user's settings. Setting this system property has no effect.</td></tr>
613 * <tr><th scope="row">{@systemProperty stdout.encoding}</th>
614 * <td>Character encoding name for {@link System#out System.out} and
615 * {@link System#console() System.console()}.
616 * The Java runtime can be started with the system property set to {@code UTF-8},
617 * starting it with the property set to another value leads to undefined behavior.
618 * <tr><th scope="row">{@systemProperty stderr.encoding}</th>
619 * <td>Character encoding name for {@link System#err System.err}.
620 * The Java runtime can be started with the system property set to {@code UTF-8},
621 * starting it with the property set to another value leads to undefined behavior.
622 * </tbody>
623 * </table>
624 * <p>
625 * The {@code java.specification.maintenance.version} property is
626 * defined if the specification implemented by this runtime at the
627 * time of its construction had undergone a <a
628 * href="https://jcp.org/en/procedures/jcp2#3.6.4">maintenance
629 * release</a>. When defined, its value identifies that
630 * maintenance release. To indicate the first maintenance release
631 * this property will have the value {@code "1"}, to indicate the
632 * second maintenance release this property will have the value
633 * {@code "2"}, and so on.
634 * <p>
635 * Multiple paths in a system property value are separated by the path
636 * separator character of the platform.
637 * <p>
638 * Additional locale-related system properties defined by the
639 * {@link Locale##default_locale Default Locale} section in the {@code Locale}
640 * class description may also be obtained with this method.
641 *
642 * @apiNote
643 * <strong>Changing a standard system property may have unpredictable results
644 * unless otherwise specified.</strong>
645 * Property values may be cached during initialization or on first use.
646 * Setting a standard property after initialization using {@link #getProperties()},
647 * {@link #setProperties(Properties)}, {@link #setProperty(String, String)}, or
648 * {@link #clearProperty(String)} may not have the desired effect.
649 *
650 * @implNote
651 * In addition to the standard system properties, the system
652 * properties may include the following keys:
653 * <table class="striped">
654 * <caption style="display:none">Shows property keys and associated values</caption>
655 * <thead>
656 * <tr><th scope="col">Key</th>
657 * <th scope="col">Description of Associated Value</th></tr>
658 * </thead>
659 * <tbody>
660 * <tr><th scope="row">{@systemProperty jdk.module.path}</th>
661 * <td>The application module path</td></tr>
662 * <tr><th scope="row">{@systemProperty jdk.module.upgrade.path}</th>
663 * <td>The upgrade module path</td></tr>
664 * <tr><th scope="row">{@systemProperty jdk.module.main}</th>
665 * <td>The module name of the initial/main module</td></tr>
666 * <tr><th scope="row">{@systemProperty jdk.module.main.class}</th>
667 * <td>The main class name of the initial module</td></tr>
668 * <tr><th scope="row">{@systemProperty file.encoding}</th>
669 * <td>The name of the default charset, defaults to {@code UTF-8}.
670 * The property may be set on the command line to the value
671 * {@code UTF-8} or {@code COMPAT}. If set on the command line to
672 * the value {@code COMPAT} then the value is replaced with the
673 * value of the {@code native.encoding} property during startup.
674 * Setting the property to a value other than {@code UTF-8} or
675 * {@code COMPAT} leads to unspecified behavior.
676 * </td></tr>
677 * </tbody>
678 * </table>
679 *
680 * @return the system properties
681 * @see #setProperties
682 * @see java.util.Properties
683 */
684 public static Properties getProperties() {
685 @SuppressWarnings("removal")
686 SecurityManager sm = getSecurityManager();
687 if (sm != null) {
688 sm.checkPropertiesAccess();
689 }
690
691 return props;
692 }
693
694 /**
695 * Returns the system-dependent line separator string. It always
696 * returns the same value - the initial value of the {@linkplain
697 * #getProperty(String) system property} {@code line.separator}.
698 *
699 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
700 * Windows systems it returns {@code "\r\n"}.
701 *
702 * @return the system-dependent line separator string
703 * @since 1.7
704 */
705 public static String lineSeparator() {
706 return lineSeparator;
707 }
708
709 private static String lineSeparator;
710
711 /**
712 * Sets the system properties to the {@code Properties} argument.
713 * <p>
714 * The argument becomes the current set of system properties for use
715 * by the {@link #getProperty(String)} method. If the argument is
716 * {@code null}, then the current set of system properties is
717 * forgotten.
718 *
719 * @apiNote
720 * <strong>Changing a standard system property may have unpredictable results
721 * unless otherwise specified</strong>.
722 * See {@linkplain #getProperties getProperties} for details.
723 *
724 * @param props the new system properties.
725 * @see #getProperties
726 * @see java.util.Properties
727 */
728 public static void setProperties(Properties props) {
729 @SuppressWarnings("removal")
730 SecurityManager sm = getSecurityManager();
731 if (sm != null) {
732 sm.checkPropertiesAccess();
733 }
734
735 if (props == null) {
736 Map<String, String> tempProps = SystemProps.initProperties();
737 VersionProps.init(tempProps);
738 props = createProperties(tempProps);
739 }
740 System.props = props;
741 }
742
743 /**
744 * Gets the system property indicated by the specified key.
745 * <p>
746 * If there is no current set of system properties, a set of system
747 * properties is first created and initialized in the same manner as
748 * for the {@code getProperties} method.
749 *
750 * @apiNote
751 * <strong>Changing a standard system property may have unpredictable results
752 * unless otherwise specified</strong>.
753 * See {@linkplain #getProperties getProperties} for details.
754 *
755 * @param key the name of the system property.
756 * @return the string value of the system property,
757 * or {@code null} if there is no property with that key.
758 *
759 * @throws NullPointerException if {@code key} is {@code null}.
760 * @throws IllegalArgumentException if {@code key} is empty.
761 * @see #setProperty
762 * @see java.lang.System#getProperties()
763 */
764 public static String getProperty(String key) {
765 checkKey(key);
766 @SuppressWarnings("removal")
767 SecurityManager sm = getSecurityManager();
768 if (sm != null) {
769 sm.checkPropertyAccess(key);
770 }
771
772 return props.getProperty(key);
773 }
774
775 /**
776 * Gets the system property indicated by the specified key.
777 * <p>
778 * If there is no current set of system properties, a set of system
779 * properties is first created and initialized in the same manner as
780 * for the {@code getProperties} method.
781 *
782 * @param key the name of the system property.
783 * @param def a default value.
784 * @return the string value of the system property,
785 * or the default value if there is no property with that key.
786 *
787 * @throws NullPointerException if {@code key} is {@code null}.
788 * @throws IllegalArgumentException if {@code key} is empty.
789 * @see #setProperty
790 * @see java.lang.System#getProperties()
791 */
792 public static String getProperty(String key, String def) {
793 checkKey(key);
794 @SuppressWarnings("removal")
795 SecurityManager sm = getSecurityManager();
796 if (sm != null) {
797 sm.checkPropertyAccess(key);
798 }
799
800 return props.getProperty(key, def);
801 }
802
803 /**
804 * Sets the system property indicated by the specified key.
805 *
806 * @apiNote
807 * <strong>Changing a standard system property may have unpredictable results
808 * unless otherwise specified</strong>.
809 * See {@linkplain #getProperties getProperties} for details.
810 *
811 * @param key the name of the system property.
812 * @param value the value of the system property.
813 * @return the previous value of the system property,
814 * or {@code null} if it did not have one.
815 *
816 * @throws NullPointerException if {@code key} or
817 * {@code value} is {@code null}.
818 * @throws IllegalArgumentException if {@code key} is empty.
819 * @see #getProperty
820 * @see java.lang.System#getProperty(java.lang.String)
821 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
822 * @since 1.2
823 */
824 public static String setProperty(String key, String value) {
825 checkKey(key);
826 @SuppressWarnings("removal")
827 SecurityManager sm = getSecurityManager();
828 if (sm != null) {
829 sm.checkPermission(new PropertyPermission(key,
830 SecurityConstants.PROPERTY_WRITE_ACTION));
831 }
832
833 return (String) props.setProperty(key, value);
834 }
835
836 /**
837 * Removes the system property indicated by the specified key.
838 *
839 * @apiNote
840 * <strong>Changing a standard system property may have unpredictable results
841 * unless otherwise specified</strong>.
842 * See {@linkplain #getProperties getProperties} method for details.
843 *
844 * @param key the name of the system property to be removed.
845 * @return the previous string value of the system property,
846 * or {@code null} if there was no property with that key.
847 *
848 * @throws NullPointerException if {@code key} is {@code null}.
849 * @throws IllegalArgumentException if {@code key} is empty.
850 * @see #getProperty
851 * @see #setProperty
852 * @see java.util.Properties
853 * @since 1.5
854 */
855 public static String clearProperty(String key) {
856 checkKey(key);
857 @SuppressWarnings("removal")
858 SecurityManager sm = getSecurityManager();
859 if (sm != null) {
860 sm.checkPermission(new PropertyPermission(key, "write"));
861 }
862
863 return (String) props.remove(key);
864 }
865
866 private static void checkKey(String key) {
867 if (key == null) {
868 throw new NullPointerException("key can't be null");
869 }
870 if (key.isEmpty()) {
871 throw new IllegalArgumentException("key can't be empty");
872 }
873 }
874
875 /**
876 * Gets the value of the specified environment variable. An
877 * environment variable is a system-dependent external named
878 * value.
879 *
880 * <p><a id="EnvironmentVSSystemProperties"><i>System
881 * properties</i> and <i>environment variables</i></a> are both
882 * conceptually mappings between names and values. Both
883 * mechanisms can be used to pass user-defined information to a
884 * Java process. Environment variables have a more global effect,
885 * because they are visible to all descendants of the process
886 * which defines them, not just the immediate Java subprocess.
887 * They can have subtly different semantics, such as case
888 * insensitivity, on different operating systems. For these
889 * reasons, environment variables are more likely to have
890 * unintended side effects. It is best to use system properties
891 * where possible. Environment variables should be used when a
892 * global effect is desired, or when an external system interface
893 * requires an environment variable (such as {@code PATH}).
894 *
895 * <p>On UNIX systems the alphabetic case of {@code name} is
896 * typically significant, while on Microsoft Windows systems it is
897 * typically not. For example, the expression
898 * {@code System.getenv("FOO").equals(System.getenv("foo"))}
899 * is likely to be true on Microsoft Windows.
900 *
901 * @param name the name of the environment variable
902 * @return the string value of the variable, or {@code null}
903 * if the variable is not defined in the system environment
904 * @throws NullPointerException if {@code name} is {@code null}
905 * @see #getenv()
906 * @see ProcessBuilder#environment()
907 */
908 public static String getenv(String name) {
909 @SuppressWarnings("removal")
910 SecurityManager sm = getSecurityManager();
911 if (sm != null) {
912 sm.checkPermission(new RuntimePermission("getenv."+name));
913 }
914
915 return ProcessEnvironment.getenv(name);
916 }
917
918
919 /**
920 * Returns an unmodifiable string map view of the current system environment.
921 * The environment is a system-dependent mapping from names to
922 * values which is passed from parent to child processes.
923 *
924 * <p>If the system does not support environment variables, an
925 * empty map is returned.
926 *
927 * <p>The returned map will never contain null keys or values.
928 * Attempting to query the presence of a null key or value will
929 * throw a {@link NullPointerException}. Attempting to query
930 * the presence of a key or value which is not of type
931 * {@link String} will throw a {@link ClassCastException}.
932 *
933 * <p>The returned map and its collection views may not obey the
934 * general contract of the {@link Object#equals} and
935 * {@link Object#hashCode} methods.
936 *
937 * <p>The returned map is typically case-sensitive on all platforms.
938 *
939 * <p>When passing information to a Java subprocess,
940 * <a href=#EnvironmentVSSystemProperties>system properties</a>
941 * are generally preferred over environment variables.
942 *
943 * @return the environment as a map of variable names to values
944 * @see #getenv(String)
945 * @see ProcessBuilder#environment()
946 * @since 1.5
947 */
948 public static java.util.Map<String,String> getenv() {
949 @SuppressWarnings("removal")
950 SecurityManager sm = getSecurityManager();
951 if (sm != null) {
952 sm.checkPermission(new RuntimePermission("getenv.*"));
953 }
954
955 return ProcessEnvironment.getenv();
956 }
957
958 /**
959 * {@code System.Logger} instances log messages that will be
960 * routed to the underlying logging framework the {@link System.LoggerFinder
961 * LoggerFinder} uses.
962 *
963 * {@code System.Logger} instances are typically obtained from
964 * the {@link java.lang.System System} class, by calling
965 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
966 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
967 * System.getLogger(loggerName, bundle)}.
968 *
969 * @see java.lang.System#getLogger(java.lang.String)
970 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
971 * @see java.lang.System.LoggerFinder
972 *
973 * @since 9
974 */
975 public interface Logger {
976
977 /**
978 * System {@linkplain Logger loggers} levels.
979 *
980 * A level has a {@linkplain #getName() name} and {@linkplain
981 * #getSeverity() severity}.
982 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
983 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
984 * by order of increasing severity.
985 * <br>
986 * {@link #ALL} and {@link #OFF}
987 * are simple markers with severities mapped respectively to
988 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
989 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
990 * <p>
991 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
992 * <p>
993 * {@linkplain System.Logger.Level System logger levels} are mapped to
994 * {@linkplain java.logging/java.util.logging.Level java.util.logging levels}
995 * of corresponding severity.
996 * <br>The mapping is as follows:
997 * <br><br>
998 * <table class="striped">
999 * <caption>System.Logger Severity Level Mapping</caption>
1000 * <thead>
1001 * <tr><th scope="col">System.Logger Levels</th>
1002 * <th scope="col">java.util.logging Levels</th>
1003 * </thead>
1004 * <tbody>
1005 * <tr><th scope="row">{@link Logger.Level#ALL ALL}</th>
1006 * <td>{@link java.logging/java.util.logging.Level#ALL ALL}</td>
1007 * <tr><th scope="row">{@link Logger.Level#TRACE TRACE}</th>
1008 * <td>{@link java.logging/java.util.logging.Level#FINER FINER}</td>
1009 * <tr><th scope="row">{@link Logger.Level#DEBUG DEBUG}</th>
1010 * <td>{@link java.logging/java.util.logging.Level#FINE FINE}</td>
1011 * <tr><th scope="row">{@link Logger.Level#INFO INFO}</th>
1012 * <td>{@link java.logging/java.util.logging.Level#INFO INFO}</td>
1013 * <tr><th scope="row">{@link Logger.Level#WARNING WARNING}</th>
1014 * <td>{@link java.logging/java.util.logging.Level#WARNING WARNING}</td>
1015 * <tr><th scope="row">{@link Logger.Level#ERROR ERROR}</th>
1016 * <td>{@link java.logging/java.util.logging.Level#SEVERE SEVERE}</td>
1017 * <tr><th scope="row">{@link Logger.Level#OFF OFF}</th>
1018 * <td>{@link java.logging/java.util.logging.Level#OFF OFF}</td>
1019 * </tbody>
1020 * </table>
1021 *
1022 * @since 9
1023 *
1024 * @see java.lang.System.LoggerFinder
1025 * @see java.lang.System.Logger
1026 */
1027 @SuppressWarnings("doclint:reference") // cross-module links
1028 public enum Level {
1029
1030 // for convenience, we're reusing java.util.logging.Level int values
1031 // the mapping logic in sun.util.logging.PlatformLogger depends
1032 // on this.
1033 /**
1034 * A marker to indicate that all levels are enabled.
1035 * This level {@linkplain #getSeverity() severity} is
1036 * {@link Integer#MIN_VALUE}.
1037 */
1038 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
1039 /**
1040 * {@code TRACE} level: usually used to log diagnostic information.
1041 * This level {@linkplain #getSeverity() severity} is
1042 * {@code 400}.
1043 */
1044 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1045 /**
1046 * {@code DEBUG} level: usually used to log debug information traces.
1047 * This level {@linkplain #getSeverity() severity} is
1048 * {@code 500}.
1049 */
1050 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1051 /**
1052 * {@code INFO} level: usually used to log information messages.
1053 * This level {@linkplain #getSeverity() severity} is
1054 * {@code 800}.
1055 */
1056 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1057 /**
1058 * {@code WARNING} level: usually used to log warning messages.
1059 * This level {@linkplain #getSeverity() severity} is
1060 * {@code 900}.
1061 */
1062 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1063 /**
1064 * {@code ERROR} level: usually used to log error messages.
1065 * This level {@linkplain #getSeverity() severity} is
1066 * {@code 1000}.
1067 */
1068 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1069 /**
1070 * A marker to indicate that all levels are disabled.
1071 * This level {@linkplain #getSeverity() severity} is
1072 * {@link Integer#MAX_VALUE}.
1073 */
1074 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1075
1076 private final int severity;
1077
1078 private Level(int severity) {
1079 this.severity = severity;
1080 }
1081
1082 /**
1083 * Returns the name of this level.
1084 * @return this level {@linkplain #name()}.
1085 */
1086 public final String getName() {
1087 return name();
1088 }
1089
1090 /**
1091 * Returns the severity of this level.
1092 * A higher severity means a more severe condition.
1093 * @return this level severity.
1094 */
1095 public final int getSeverity() {
1096 return severity;
1097 }
1098 }
1099
1100 /**
1101 * Returns the name of this logger.
1102 *
1103 * @return the logger name.
1104 */
1105 public String getName();
1106
1107 /**
1108 * Checks if a message of the given level would be logged by
1109 * this logger.
1110 *
1111 * @param level the log message level.
1112 * @return {@code true} if the given log message level is currently
1113 * being logged.
1114 *
1115 * @throws NullPointerException if {@code level} is {@code null}.
1116 */
1117 public boolean isLoggable(Level level);
1118
1119 /**
1120 * Logs a message.
1121 *
1122 * @implSpec The default implementation for this method calls
1123 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1124 *
1125 * @param level the log message level.
1126 * @param msg the string message (or a key in the message catalog, if
1127 * this logger is a {@link
1128 * LoggerFinder#getLocalizedLogger(java.lang.String,
1129 * java.util.ResourceBundle, java.lang.Module) localized logger});
1130 * can be {@code null}.
1131 *
1132 * @throws NullPointerException if {@code level} is {@code null}.
1133 */
1134 public default void log(Level level, String msg) {
1135 log(level, (ResourceBundle) null, msg, (Object[]) null);
1136 }
1137
1138 /**
1139 * Logs a lazily supplied message.
1140 *
1141 * If the logger is currently enabled for the given log message level
1142 * then a message is logged that is the result produced by the
1143 * given supplier function. Otherwise, the supplier is not operated on.
1144 *
1145 * @implSpec When logging is enabled for the given level, the default
1146 * implementation for this method calls
1147 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1148 *
1149 * @param level the log message level.
1150 * @param msgSupplier a supplier function that produces a message.
1151 *
1152 * @throws NullPointerException if {@code level} is {@code null},
1153 * or {@code msgSupplier} is {@code null}.
1154 */
1155 public default void log(Level level, Supplier<String> msgSupplier) {
1156 Objects.requireNonNull(msgSupplier);
1157 if (isLoggable(Objects.requireNonNull(level))) {
1158 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1159 }
1160 }
1161
1162 /**
1163 * Logs a message produced from the given object.
1164 *
1165 * If the logger is currently enabled for the given log message level then
1166 * a message is logged that, by default, is the result produced from
1167 * calling toString on the given object.
1168 * Otherwise, the object is not operated on.
1169 *
1170 * @implSpec When logging is enabled for the given level, the default
1171 * implementation for this method calls
1172 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1173 *
1174 * @param level the log message level.
1175 * @param obj the object to log.
1176 *
1177 * @throws NullPointerException if {@code level} is {@code null}, or
1178 * {@code obj} is {@code null}.
1179 */
1180 public default void log(Level level, Object obj) {
1181 Objects.requireNonNull(obj);
1182 if (isLoggable(Objects.requireNonNull(level))) {
1183 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1184 }
1185 }
1186
1187 /**
1188 * Logs a message associated with a given throwable.
1189 *
1190 * @implSpec The default implementation for this method calls
1191 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1192 *
1193 * @param level the log message level.
1194 * @param msg the string message (or a key in the message catalog, if
1195 * this logger is a {@link
1196 * LoggerFinder#getLocalizedLogger(java.lang.String,
1197 * java.util.ResourceBundle, java.lang.Module) localized logger});
1198 * can be {@code null}.
1199 * @param thrown a {@code Throwable} associated with the log message;
1200 * can be {@code null}.
1201 *
1202 * @throws NullPointerException if {@code level} is {@code null}.
1203 */
1204 public default void log(Level level, String msg, Throwable thrown) {
1205 this.log(level, null, msg, thrown);
1206 }
1207
1208 /**
1209 * Logs a lazily supplied message associated with a given throwable.
1210 *
1211 * If the logger is currently enabled for the given log message level
1212 * then a message is logged that is the result produced by the
1213 * given supplier function. Otherwise, the supplier is not operated on.
1214 *
1215 * @implSpec When logging is enabled for the given level, the default
1216 * implementation for this method calls
1217 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1218 *
1219 * @param level one of the log message level identifiers.
1220 * @param msgSupplier a supplier function that produces a message.
1221 * @param thrown a {@code Throwable} associated with log message;
1222 * can be {@code null}.
1223 *
1224 * @throws NullPointerException if {@code level} is {@code null}, or
1225 * {@code msgSupplier} is {@code null}.
1226 */
1227 public default void log(Level level, Supplier<String> msgSupplier,
1228 Throwable thrown) {
1229 Objects.requireNonNull(msgSupplier);
1230 if (isLoggable(Objects.requireNonNull(level))) {
1231 this.log(level, null, msgSupplier.get(), thrown);
1232 }
1233 }
1234
1235 /**
1236 * Logs a message with an optional list of parameters.
1237 *
1238 * @implSpec The default implementation for this method calls
1239 * {@code this.log(level, (ResourceBundle)null, format, params);}
1240 *
1241 * @param level one of the log message level identifiers.
1242 * @param format the string message format in {@link
1243 * java.text.MessageFormat} format, (or a key in the message
1244 * catalog, if this logger is a {@link
1245 * LoggerFinder#getLocalizedLogger(java.lang.String,
1246 * java.util.ResourceBundle, java.lang.Module) localized logger});
1247 * can be {@code null}.
1248 * @param params an optional list of parameters to the message (may be
1249 * none).
1250 *
1251 * @throws NullPointerException if {@code level} is {@code null}.
1252 */
1253 public default void log(Level level, String format, Object... params) {
1254 this.log(level, null, format, params);
1255 }
1256
1257 /**
1258 * Logs a localized message associated with a given throwable.
1259 *
1260 * If the given resource bundle is non-{@code null}, the {@code msg}
1261 * string is localized using the given resource bundle.
1262 * Otherwise the {@code msg} string is not localized.
1263 *
1264 * @param level the log message level.
1265 * @param bundle a resource bundle to localize {@code msg}; can be
1266 * {@code null}.
1267 * @param msg the string message (or a key in the message catalog,
1268 * if {@code bundle} is not {@code null}); can be {@code null}.
1269 * @param thrown a {@code Throwable} associated with the log message;
1270 * can be {@code null}.
1271 *
1272 * @throws NullPointerException if {@code level} is {@code null}.
1273 */
1274 public void log(Level level, ResourceBundle bundle, String msg,
1275 Throwable thrown);
1276
1277 /**
1278 * Logs a message with resource bundle and an optional list of
1279 * parameters.
1280 *
1281 * If the given resource bundle is non-{@code null}, the {@code format}
1282 * string is localized using the given resource bundle.
1283 * Otherwise the {@code format} string is not localized.
1284 *
1285 * @param level the log message level.
1286 * @param bundle a resource bundle to localize {@code format}; can be
1287 * {@code null}.
1288 * @param format the string message format in {@link
1289 * java.text.MessageFormat} format, (or a key in the message
1290 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1291 * @param params an optional list of parameters to the message (may be
1292 * none).
1293 *
1294 * @throws NullPointerException if {@code level} is {@code null}.
1295 */
1296 public void log(Level level, ResourceBundle bundle, String format,
1297 Object... params);
1298 }
1299
1300 /**
1301 * The {@code LoggerFinder} service is responsible for creating, managing,
1302 * and configuring loggers to the underlying framework it uses.
1303 *
1304 * A logger finder is a concrete implementation of this class that has a
1305 * zero-argument constructor and implements the abstract methods defined
1306 * by this class.
1307 * The loggers returned from a logger finder are capable of routing log
1308 * messages to the logging backend this provider supports.
1309 * A given invocation of the Java Runtime maintains a single
1310 * system-wide LoggerFinder instance that is loaded as follows:
1311 * <ul>
1312 * <li>First it finds any custom {@code LoggerFinder} provider
1313 * using the {@link java.util.ServiceLoader} facility with the
1314 * {@linkplain ClassLoader#getSystemClassLoader() system class
1315 * loader}.</li>
1316 * <li>If no {@code LoggerFinder} provider is found, the system default
1317 * {@code LoggerFinder} implementation will be used.</li>
1318 * </ul>
1319 * <p>
1320 * An application can replace the logging backend
1321 * <i>even when the java.logging module is present</i>, by simply providing
1322 * and declaring an implementation of the {@link LoggerFinder} service.
1323 * <p>
1324 * <b>Default Implementation</b>
1325 * <p>
1326 * The system default {@code LoggerFinder} implementation uses
1327 * {@code java.util.logging} as the backend framework when the
1328 * {@code java.logging} module is present.
1329 * It returns a {@linkplain System.Logger logger} instance
1330 * that will route log messages to a {@link java.logging/java.util.logging.Logger
1331 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1332 * present, the default implementation will return a simple logger
1333 * instance that will route log messages of {@code INFO} level and above to
1334 * the console ({@code System.err}).
1335 * <p>
1336 * <b>Logging Configuration</b>
1337 * <p>
1338 * {@linkplain Logger Logger} instances obtained from the
1339 * {@code LoggerFinder} factory methods are not directly configurable by
1340 * the application. Configuration is the responsibility of the underlying
1341 * logging backend, and usually requires using APIs specific to that backend.
1342 * <p>For the default {@code LoggerFinder} implementation
1343 * using {@code java.util.logging} as its backend, refer to
1344 * {@link java.logging/java.util.logging java.util.logging} for logging configuration.
1345 * For the default {@code LoggerFinder} implementation returning simple loggers
1346 * when the {@code java.logging} module is absent, the configuration
1347 * is implementation dependent.
1348 * <p>
1349 * Usually an application that uses a logging framework will log messages
1350 * through a logger facade defined (or supported) by that framework.
1351 * Applications that wish to use an external framework should log
1352 * through the facade associated with that framework.
1353 * <p>
1354 * A system class that needs to log messages will typically obtain
1355 * a {@link System.Logger} instance to route messages to the logging
1356 * framework selected by the application.
1357 * <p>
1358 * Libraries and classes that only need loggers to produce log messages
1359 * should not attempt to configure loggers by themselves, as that
1360 * would make them dependent from a specific implementation of the
1361 * {@code LoggerFinder} service.
1362 * <p>
1363 * <b>Message Levels and Mapping to backend levels</b>
1364 * <p>
1365 * A logger finder is responsible for mapping from a {@code
1366 * System.Logger.Level} to a level supported by the logging backend it uses.
1367 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1368 * maps {@code System.Logger} levels to
1369 * {@linkplain java.logging/java.util.logging.Level java.util.logging} levels
1370 * of corresponding severity - as described in {@link Logger.Level
1371 * Logger.Level}.
1372 *
1373 * @see java.lang.System
1374 * @see java.lang.System.Logger
1375 *
1376 * @since 9
1377 */
1378 @SuppressWarnings("doclint:reference") // cross-module links
1379 public abstract static class LoggerFinder {
1380 /**
1381 * The {@code RuntimePermission("loggerFinder")} is
1382 * necessary to subclass and instantiate the {@code LoggerFinder} class,
1383 * as well as to obtain loggers from an instance of that class.
1384 */
1385 static final RuntimePermission LOGGERFINDER_PERMISSION =
1386 new RuntimePermission("loggerFinder");
1387
1388 /**
1389 * Creates a new instance of {@code LoggerFinder}.
1390 *
1391 * @implNote It is recommended that a {@code LoggerFinder} service
1392 * implementation does not perform any heavy initialization in its
1393 * constructor, in order to avoid possible risks of deadlock or class
1394 * loading cycles during the instantiation of the service provider.
1395 */
1396 protected LoggerFinder() {
1397 this(checkPermission());
1398 }
1399
1400 private LoggerFinder(Void unused) {
1401 // nothing to do.
1402 }
1403
1404 private static Void checkPermission() {
1405 @SuppressWarnings("removal")
1406 final SecurityManager sm = System.getSecurityManager();
1407 if (sm != null) {
1408 sm.checkPermission(LOGGERFINDER_PERMISSION);
1409 }
1410 return null;
1411 }
1412
1413 /**
1414 * Returns an instance of {@link Logger Logger}
1415 * for the given {@code module}.
1416 *
1417 * @param name the name of the logger.
1418 * @param module the module for which the logger is being requested.
1419 *
1420 * @return a {@link Logger logger} suitable for use within the given
1421 * module.
1422 * @throws NullPointerException if {@code name} is {@code null} or
1423 * {@code module} is {@code null}.
1424 */
1425 public abstract Logger getLogger(String name, Module module);
1426
1427 /**
1428 * Returns a localizable instance of {@link Logger Logger}
1429 * for the given {@code module}.
1430 * The returned logger will use the provided resource bundle for
1431 * message localization.
1432 *
1433 * @implSpec By default, this method calls {@link
1434 * #getLogger(java.lang.String, java.lang.Module)
1435 * this.getLogger(name, module)} to obtain a logger, then wraps that
1436 * logger in a {@link Logger} instance where all methods that do not
1437 * take a {@link ResourceBundle} as parameter are redirected to one
1438 * which does - passing the given {@code bundle} for
1439 * localization. So for instance, a call to {@link
1440 * Logger#log(Logger.Level, String) Logger.log(Level.INFO, msg)}
1441 * will end up as a call to {@link
1442 * Logger#log(Logger.Level, ResourceBundle, String, Object...)
1443 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1444 * logger instance.
1445 * Note however that by default, string messages returned by {@link
1446 * java.util.function.Supplier Supplier<String>} will not be
1447 * localized, as it is assumed that such strings are messages which are
1448 * already constructed, rather than keys in a resource bundle.
1449 * <p>
1450 * An implementation of {@code LoggerFinder} may override this method,
1451 * for example, when the underlying logging backend provides its own
1452 * mechanism for localizing log messages, then such a
1453 * {@code LoggerFinder} would be free to return a logger
1454 * that makes direct use of the mechanism provided by the backend.
1455 *
1456 * @param name the name of the logger.
1457 * @param bundle a resource bundle; can be {@code null}.
1458 * @param module the module for which the logger is being requested.
1459 * @return an instance of {@link Logger Logger} which will use the
1460 * provided resource bundle for message localization.
1461 *
1462 * @throws NullPointerException if {@code name} is {@code null} or
1463 * {@code module} is {@code null}.
1464 */
1465 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1466 Module module) {
1467 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1468 }
1469
1470 /**
1471 * Returns the {@code LoggerFinder} instance. There is one
1472 * single system-wide {@code LoggerFinder} instance in
1473 * the Java Runtime. See the class specification of how the
1474 * {@link LoggerFinder LoggerFinder} implementation is located and
1475 * loaded.
1476 *
1477 * @return the {@link LoggerFinder LoggerFinder} instance.
1478 */
1479 public static LoggerFinder getLoggerFinder() {
1480 @SuppressWarnings("removal")
1481 final SecurityManager sm = System.getSecurityManager();
1482 if (sm != null) {
1483 sm.checkPermission(LOGGERFINDER_PERMISSION);
1484 }
1485 return accessProvider();
1486 }
1487
1488
1489 private static volatile LoggerFinder service;
1490 @SuppressWarnings("removal")
1491 static LoggerFinder accessProvider() {
1492 // We do not need to synchronize: LoggerFinderLoader will
1493 // always return the same instance, so if we don't have it,
1494 // just fetch it again.
1495 LoggerFinder finder = service;
1496 if (finder == null) {
1497 PrivilegedAction<LoggerFinder> pa =
1498 () -> LoggerFinderLoader.getLoggerFinder();
1499 finder = AccessController.doPrivileged(pa, null,
1500 LOGGERFINDER_PERMISSION);
1501 if (finder instanceof TemporaryLoggerFinder) return finder;
1502 service = finder;
1503 }
1504 return finder;
1505 }
1506
1507 }
1508
1509
1510 /**
1511 * Returns an instance of {@link Logger Logger} for the caller's
1512 * use.
1513 *
1514 * @implSpec
1515 * Instances returned by this method route messages to loggers
1516 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1517 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1518 * {@code module} is the caller's module.
1519 * In cases where {@code System.getLogger} is called from a context where
1520 * there is no caller frame on the stack (e.g when called directly
1521 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1522 * To obtain a logger in such a context, use an auxiliary class that will
1523 * implicitly be identified as the caller, or use the system {@link
1524 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1525 * Note that doing the latter may eagerly initialize the underlying
1526 * logging system.
1527 *
1528 * @apiNote
1529 * This method may defer calling the {@link
1530 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1531 * LoggerFinder.getLogger} method to create an actual logger supplied by
1532 * the logging backend, for instance, to allow loggers to be obtained during
1533 * the system initialization time.
1534 *
1535 * @param name the name of the logger.
1536 * @return an instance of {@link Logger} that can be used by the calling
1537 * class.
1538 * @throws NullPointerException if {@code name} is {@code null}.
1539 * @throws IllegalCallerException if there is no Java caller frame on the
1540 * stack.
1541 *
1542 * @since 9
1543 */
1544 @CallerSensitive
1545 public static Logger getLogger(String name) {
1546 Objects.requireNonNull(name);
1547 final Class<?> caller = Reflection.getCallerClass();
1548 if (caller == null) {
1549 throw new IllegalCallerException("no caller frame");
1550 }
1551 return LazyLoggers.getLogger(name, caller.getModule());
1552 }
1553
1554 /**
1555 * Returns a localizable instance of {@link Logger
1556 * Logger} for the caller's use.
1557 * The returned logger will use the provided resource bundle for message
1558 * localization.
1559 *
1560 * @implSpec
1561 * The returned logger will perform message localization as specified
1562 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1563 * java.util.ResourceBundle, java.lang.Module)
1564 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1565 * {@code module} is the caller's module.
1566 * In cases where {@code System.getLogger} is called from a context where
1567 * there is no caller frame on the stack (e.g when called directly
1568 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1569 * To obtain a logger in such a context, use an auxiliary class that
1570 * will implicitly be identified as the caller, or use the system {@link
1571 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1572 * Note that doing the latter may eagerly initialize the underlying
1573 * logging system.
1574 *
1575 * @apiNote
1576 * This method is intended to be used after the system is fully initialized.
1577 * This method may trigger the immediate loading and initialization
1578 * of the {@link LoggerFinder} service, which may cause issues if the
1579 * Java Runtime is not ready to initialize the concrete service
1580 * implementation yet.
1581 * System classes which may be loaded early in the boot sequence and
1582 * need to log localized messages should create a logger using
1583 * {@link #getLogger(java.lang.String)} and then use the log methods that
1584 * take a resource bundle as parameter.
1585 *
1586 * @param name the name of the logger.
1587 * @param bundle a resource bundle.
1588 * @return an instance of {@link Logger} which will use the provided
1589 * resource bundle for message localization.
1590 * @throws NullPointerException if {@code name} is {@code null} or
1591 * {@code bundle} is {@code null}.
1592 * @throws IllegalCallerException if there is no Java caller frame on the
1593 * stack.
1594 *
1595 * @since 9
1596 */
1597 @SuppressWarnings("removal")
1598 @CallerSensitive
1599 public static Logger getLogger(String name, ResourceBundle bundle) {
1600 final ResourceBundle rb = Objects.requireNonNull(bundle);
1601 Objects.requireNonNull(name);
1602 final Class<?> caller = Reflection.getCallerClass();
1603 if (caller == null) {
1604 throw new IllegalCallerException("no caller frame");
1605 }
1606 final SecurityManager sm = System.getSecurityManager();
1607 // We don't use LazyLoggers if a resource bundle is specified.
1608 // Bootstrap sensitive classes in the JDK do not use resource bundles
1609 // when logging. This could be revisited later, if it needs to.
1610 if (sm != null) {
1611 final PrivilegedAction<Logger> pa =
1612 () -> LoggerFinder.accessProvider()
1613 .getLocalizedLogger(name, rb, caller.getModule());
1614 return AccessController.doPrivileged(pa, null,
1615 LoggerFinder.LOGGERFINDER_PERMISSION);
1616 }
1617 return LoggerFinder.accessProvider()
1618 .getLocalizedLogger(name, rb, caller.getModule());
1619 }
1620
1621 /**
1622 * Initiates the {@linkplain Runtime##shutdown shutdown sequence} of the Java Virtual
1623 * Machine. This method initiates the shutdown sequence (if it is not already initiated)
1624 * and then blocks indefinitely. This method neither returns nor throws an exception;
1625 * that is, it does not complete either normally or abruptly.
1626 * <p>
1627 * The argument serves as a status code. By convention, a nonzero status code
1628 * indicates abnormal termination.
1629 * <p>
1630 * The call {@code System.exit(n)} is effectively equivalent to the call:
1631 * {@snippet :
1632 * Runtime.getRuntime().exit(n)
1633 * }
1634 *
1635 * @implNote
1636 * The initiation of the shutdown sequence is logged by {@link Runtime#exit(int)}.
1637 *
1638 * @param status exit status.
1639 * @see java.lang.Runtime#exit(int)
1640 */
1641 public static void exit(int status) {
1642 Runtime.getRuntime().exit(status);
1643 }
1644
1645 /**
1646 * Runs the garbage collector in the Java Virtual Machine.
1647 * <p>
1648 * Calling the {@code gc} method suggests that the Java Virtual Machine
1649 * expend effort toward recycling unused objects in order to
1650 * make the memory they currently occupy available for reuse
1651 * by the Java Virtual Machine.
1652 * When control returns from the method call, the Java Virtual Machine
1653 * has made a best effort to reclaim space from all unused objects.
1654 * There is no guarantee that this effort will recycle any particular
1655 * number of unused objects, reclaim any particular amount of space, or
1656 * complete at any particular time, if at all, before the method returns or ever.
1657 * There is also no guarantee that this effort will determine
1658 * the change of reachability in any particular number of objects,
1659 * or that any particular number of {@link java.lang.ref.Reference Reference}
1660 * objects will be cleared and enqueued.
1661 *
1662 * <p>
1663 * The call {@code System.gc()} is effectively equivalent to the
1664 * call:
1665 * <blockquote><pre>
1666 * Runtime.getRuntime().gc()
1667 * </pre></blockquote>
1668 *
1669 * @see java.lang.Runtime#gc()
1670 */
1671 public static void gc() {
1672 Runtime.getRuntime().gc();
1673 }
1674
1675 /**
1676 * Runs the finalization methods of any objects pending finalization.
1677 *
1678 * Calling this method suggests that the Java Virtual Machine expend
1679 * effort toward running the {@code finalize} methods of objects
1680 * that have been found to be discarded but whose {@code finalize}
1681 * methods have not yet been run. When control returns from the
1682 * method call, the Java Virtual Machine has made a best effort to
1683 * complete all outstanding finalizations.
1684 * <p>
1685 * The call {@code System.runFinalization()} is effectively
1686 * equivalent to the call:
1687 * <blockquote><pre>
1688 * Runtime.getRuntime().runFinalization()
1689 * </pre></blockquote>
1690 *
1691 * @deprecated Finalization has been deprecated for removal. See
1692 * {@link java.lang.Object#finalize} for background information and details
1693 * about migration options.
1694 * <p>
1695 * When running in a JVM in which finalization has been disabled or removed,
1696 * no objects will be pending finalization, so this method does nothing.
1697 *
1698 * @see java.lang.Runtime#runFinalization()
1699 * @jls 12.6 Finalization of Class Instances
1700 */
1701 @Deprecated(since="18", forRemoval=true)
1702 @SuppressWarnings("removal")
1703 public static void runFinalization() {
1704 Runtime.getRuntime().runFinalization();
1705 }
1706
1707 /**
1708 * Loads the native library specified by the filename argument. The filename
1709 * argument must be an absolute path name.
1710 *
1711 * If the filename argument, when stripped of any platform-specific library
1712 * prefix, path, and file extension, indicates a library whose name is,
1713 * for example, L, and a native library called L is statically linked
1714 * with the VM, then the JNI_OnLoad_L function exported by the library
1715 * is invoked rather than attempting to load a dynamic library.
1716 * A filename matching the argument does not have to exist in the
1717 * file system.
1718 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1719 * for more details.
1720 *
1721 * Otherwise, the filename argument is mapped to a native library image in
1722 * an implementation-dependent manner.
1723 *
1724 * <p>
1725 * The call {@code System.load(name)} is effectively equivalent
1726 * to the call:
1727 * <blockquote><pre>
1728 * Runtime.getRuntime().load(name)
1729 * </pre></blockquote>
1730 *
1731 * @param filename the file to load.
1732 * @throws UnsatisfiedLinkError if either the filename is not an
1733 * absolute path name, the native library is not statically
1734 * linked with the VM, or the library cannot be mapped to
1735 * a native library image by the host system.
1736 * @throws NullPointerException if {@code filename} is {@code null}
1737 * @throws IllegalCallerException if the caller is in a module that
1738 * does not have native access enabled.
1739 *
1740 * @spec jni/index.html Java Native Interface Specification
1741 * @see java.lang.Runtime#load(java.lang.String)
1742 */
1743 @CallerSensitive
1744 @Restricted
1745 public static void load(String filename) {
1746 Class<?> caller = Reflection.getCallerClass();
1747 Reflection.ensureNativeAccess(caller, System.class, "load", false);
1748 Runtime.getRuntime().load0(caller, filename);
1749 }
1750
1751 /**
1752 * Loads the native library specified by the {@code libname}
1753 * argument. The {@code libname} argument must not contain any platform
1754 * specific prefix, file extension or path. If a native library
1755 * called {@code libname} is statically linked with the VM, then the
1756 * JNI_OnLoad_{@code libname} function exported by the library is invoked.
1757 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1758 * for more details.
1759 *
1760 * Otherwise, the libname argument is loaded from a system library
1761 * location and mapped to a native library image in an
1762 * implementation-dependent manner.
1763 * <p>
1764 * The call {@code System.loadLibrary(name)} is effectively
1765 * equivalent to the call
1766 * <blockquote><pre>
1767 * Runtime.getRuntime().loadLibrary(name)
1768 * </pre></blockquote>
1769 *
1770 * @param libname the name of the library.
1771 * @throws UnsatisfiedLinkError if either the libname argument
1772 * contains a file path, the native library is not statically
1773 * linked with the VM, or the library cannot be mapped to a
1774 * native library image by the host system.
1775 * @throws NullPointerException if {@code libname} is {@code null}
1776 * @throws IllegalCallerException if the caller is in a module that
1777 * does not have native access enabled.
1778 *
1779 * @spec jni/index.html Java Native Interface Specification
1780 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1781 */
1782 @CallerSensitive
1783 @Restricted
1784 public static void loadLibrary(String libname) {
1785 Class<?> caller = Reflection.getCallerClass();
1786 Reflection.ensureNativeAccess(caller, System.class, "loadLibrary", false);
1787 Runtime.getRuntime().loadLibrary0(caller, libname);
1788 }
1789
1790 /**
1791 * Maps a library name into a platform-specific string representing
1792 * a native library.
1793 *
1794 * @param libname the name of the library.
1795 * @return a platform-dependent native library name.
1796 * @throws NullPointerException if {@code libname} is {@code null}
1797 * @see java.lang.System#loadLibrary(java.lang.String)
1798 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1799 * @since 1.2
1800 */
1801 public static native String mapLibraryName(String libname);
1802
1803 /**
1804 * Create PrintStream for stdout/err based on encoding.
1805 */
1806 private static PrintStream newPrintStream(OutputStream out, String enc) {
1807 if (enc != null) {
1808 return new PrintStream(new BufferedOutputStream(out, 128), true,
1809 Charset.forName(enc, UTF_8.INSTANCE));
1810 }
1811 return new PrintStream(new BufferedOutputStream(out, 128), true);
1812 }
1813
1814 /**
1815 * Logs an exception/error at initialization time to stdout or stderr.
1816 *
1817 * @param printToStderr to print to stderr rather than stdout
1818 * @param printStackTrace to print the stack trace
1819 * @param msg the message to print before the exception, can be {@code null}
1820 * @param e the exception or error
1821 */
1822 private static void logInitException(boolean printToStderr,
1823 boolean printStackTrace,
1824 String msg,
1825 Throwable e) {
1826 if (VM.initLevel() < 1) {
1827 throw new InternalError("system classes not initialized");
1828 }
1829 PrintStream log = (printToStderr) ? err : out;
1830 if (msg != null) {
1831 log.println(msg);
1832 }
1833 if (printStackTrace) {
1834 e.printStackTrace(log);
1835 } else {
1836 log.println(e);
1837 for (Throwable suppressed : e.getSuppressed()) {
1838 log.println("Suppressed: " + suppressed);
1839 }
1840 Throwable cause = e.getCause();
1841 if (cause != null) {
1842 log.println("Caused by: " + cause);
1843 }
1844 }
1845 }
1846
1847 /**
1848 * Create the Properties object from a map - masking out system properties
1849 * that are not intended for public access.
1850 */
1851 private static Properties createProperties(Map<String, String> initialProps) {
1852 Properties properties = new Properties(initialProps.size());
1853 for (var entry : initialProps.entrySet()) {
1854 String prop = entry.getKey();
1855 switch (prop) {
1856 // Do not add private system properties to the Properties
1857 case "sun.nio.MaxDirectMemorySize":
1858 case "sun.nio.PageAlignDirectMemory":
1859 // used by java.lang.Integer.IntegerCache
1860 case "java.lang.Integer.IntegerCache.high":
1861 // used by sun.launcher.LauncherHelper
1862 case "sun.java.launcher.diag":
1863 // used by jdk.internal.loader.ClassLoaders
1864 case "jdk.boot.class.path.append":
1865 break;
1866 default:
1867 properties.put(prop, entry.getValue());
1868 }
1869 }
1870 return properties;
1871 }
1872
1873 /**
1874 * Initialize the system class. Called after thread initialization.
1875 */
1876 private static void initPhase1() {
1877
1878 // register the shared secrets - do this first, since SystemProps.initProperties
1879 // might initialize CharsetDecoders that rely on it
1880 setJavaLangAccess();
1881
1882 // VM might invoke JNU_NewStringPlatform() to set those encoding
1883 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1884 // during "props" initialization.
1885 // The charset is initialized in System.c and does not depend on the Properties.
1886 Map<String, String> tempProps = SystemProps.initProperties();
1887 VersionProps.init(tempProps);
1888
1889 // There are certain system configurations that may be controlled by
1890 // VM options such as the maximum amount of direct memory and
1891 // Integer cache size used to support the object identity semantics
1892 // of autoboxing. Typically, the library will obtain these values
1893 // from the properties set by the VM. If the properties are for
1894 // internal implementation use only, these properties should be
1895 // masked from the system properties.
1896 //
1897 // Save a private copy of the system properties object that
1898 // can only be accessed by the internal implementation.
1899 VM.saveProperties(tempProps);
1900 props = createProperties(tempProps);
1901
1902 // Check if sun.jnu.encoding is supported. If not, replace it with UTF-8.
1903 var jnuEncoding = props.getProperty("sun.jnu.encoding");
1904 if (jnuEncoding == null || !Charset.isSupported(jnuEncoding)) {
1905 notSupportedJnuEncoding = jnuEncoding == null ? "null" : jnuEncoding;
1906 props.setProperty("sun.jnu.encoding", "UTF-8");
1907 }
1908
1909 StaticProperty.javaHome(); // Load StaticProperty to cache the property values
1910
1911 lineSeparator = props.getProperty("line.separator");
1912
1913 FileInputStream fdIn = new In(FileDescriptor.in);
1914 FileOutputStream fdOut = new Out(FileDescriptor.out);
1915 FileOutputStream fdErr = new Out(FileDescriptor.err);
1916 initialIn = new BufferedInputStream(fdIn);
1917 setIn0(initialIn);
1918 // stdout/err.encoding are set when the VM is associated with the terminal,
1919 // thus they are equivalent to Console.charset(), otherwise the encodings
1920 // of those properties default to native.encoding
1921 setOut0(newPrintStream(fdOut, props.getProperty("stdout.encoding")));
1922 initialErr = newPrintStream(fdErr, props.getProperty("stderr.encoding"));
1923 setErr0(initialErr);
1924
1925 // Setup Java signal handlers for HUP, TERM, and INT (where available).
1926 Terminator.setup();
1927
1928 // Initialize any miscellaneous operating system settings that need to be
1929 // set for the class libraries. Currently this is no-op everywhere except
1930 // for Windows where the process-wide error mode is set before the java.io
1931 // classes are used.
1932 VM.initializeOSEnvironment();
1933
1934 // start Finalizer and Reference Handler threads
1935 SharedSecrets.getJavaLangRefAccess().startThreads();
1936
1937 // system properties, java.lang and other core classes are now initialized
1938 VM.initLevel(1);
1939 }
1940
1941 /**
1942 * System.in.
1943 */
1944 private static class In extends FileInputStream {
1945 In(FileDescriptor fd) {
1946 super(fd);
1947 }
1948
1949 @Override
1950 public int read() throws IOException {
1951 boolean attempted = Blocker.begin();
1952 try {
1953 return super.read();
1954 } finally {
1955 Blocker.end(attempted);
1956 }
1957 }
1958
1959 @Override
1960 public int read(byte[] b) throws IOException {
1961 boolean attempted = Blocker.begin();
1962 try {
1963 return super.read(b);
1964 } finally {
1965 Blocker.end(attempted);
1966 }
1967 }
1968
1969 @Override
1970 public int read(byte[] b, int off, int len) throws IOException {
1971 boolean attempted = Blocker.begin();
1972 try {
1973 return super.read(b, off, len);
1974 } finally {
1975 Blocker.end(attempted);
1976 }
1977 }
1978 }
1979
1980 /**
1981 * System.out/System.err wrap this output stream.
1982 */
1983 private static class Out extends FileOutputStream {
1984 Out(FileDescriptor fd) {
1985 super(fd);
1986 }
1987
1988 @Override
1989 public void write(int b) throws IOException {
1990 boolean attempted = Blocker.begin();
1991 try {
1992 super.write(b);
1993 } finally {
1994 Blocker.end(attempted);
1995 }
1996 }
1997
1998 @Override
1999 public void write(byte[] b) throws IOException {
2000 boolean attempted = Blocker.begin();
2001 try {
2002 super.write(b);
2003 } finally {
2004 Blocker.end(attempted);
2005 }
2006 }
2007
2008 @Override
2009 public void write(byte[] b, int off, int len) throws IOException {
2010 boolean attempted = Blocker.begin();
2011 try {
2012 super.write(b, off, len);
2013 } finally {
2014 Blocker.end(attempted);
2015 }
2016 }
2017 }
2018
2019 // @see #initPhase2()
2020 static ModuleLayer bootLayer;
2021
2022 /*
2023 * Invoked by VM. Phase 2 module system initialization.
2024 * Only classes in java.base can be loaded in this phase.
2025 *
2026 * @param printToStderr print exceptions to stderr rather than stdout
2027 * @param printStackTrace print stack trace when exception occurs
2028 *
2029 * @return JNI_OK for success, JNI_ERR for failure
2030 */
2031 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
2032
2033 try {
2034 bootLayer = ModuleBootstrap.boot();
2035 } catch (Exception | Error e) {
2036 logInitException(printToStderr, printStackTrace,
2037 "Error occurred during initialization of boot layer", e);
2038 return -1; // JNI_ERR
2039 }
2040
2041 // module system initialized
2042 VM.initLevel(2);
2043
2044 return 0; // JNI_OK
2045 }
2046
2047 /*
2048 * Invoked by VM. Phase 3 is the final system initialization:
2049 * 1. set system class loader
2050 * 2. set TCCL
2051 *
2052 * This method must be called after the module system initialization.
2053 */
2054 private static void initPhase3() {
2055
2056 // Emit a warning if java.io.tmpdir is set via the command line
2057 // to a directory that doesn't exist
2058 if (SystemProps.isBadIoTmpdir()) {
2059 System.err.println("WARNING: java.io.tmpdir directory does not exist");
2060 }
2061
2062 String smProp = System.getProperty("java.security.manager");
2063 if (smProp != null) {
2064 switch (smProp) {
2065 case "disallow":
2066 break;
2067 case "allow":
2068 case "":
2069 case "default":
2070 default:
2071 throw new Error("A command line option has attempted to allow or enable the Security Manager."
2072 + " Enabling a Security Manager is not supported.");
2073 }
2074 }
2075
2076 // Emit a warning if `sun.jnu.encoding` is not supported.
2077 if (notSupportedJnuEncoding != null) {
2078 System.err.println(
2079 "WARNING: The encoding of the underlying platform's" +
2080 " file system is not supported: " +
2081 notSupportedJnuEncoding);
2082 }
2083
2084 // initializing the system class loader
2085 VM.initLevel(3);
2086
2087 // system class loader initialized
2088 ClassLoader scl = ClassLoader.initSystemClassLoader();
2089
2090 // set TCCL
2091 Thread.currentThread().setContextClassLoader(scl);
2092
2093 // system is fully initialized
2094 VM.initLevel(4);
2095 }
2096
2097 private static void setJavaLangAccess() {
2098 // Allow privileged classes outside of java.lang
2099 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2100 public List<Method> getDeclaredPublicMethods(Class<?> klass, String name, Class<?>... parameterTypes) {
2101 return klass.getDeclaredPublicMethods(name, parameterTypes);
2102 }
2103 public Method findMethod(Class<?> klass, boolean publicOnly, String name, Class<?>... parameterTypes) {
2104 return klass.findMethod(publicOnly, name, parameterTypes);
2105 }
2106 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2107 return klass.getConstantPool();
2108 }
2109 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2110 return klass.casAnnotationType(oldType, newType);
2111 }
2112 public AnnotationType getAnnotationType(Class<?> klass) {
2113 return klass.getAnnotationType();
2114 }
2115 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2116 return klass.getDeclaredAnnotationMap();
2117 }
2118 public byte[] getRawClassAnnotations(Class<?> klass) {
2119 return klass.getRawAnnotations();
2120 }
2121 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2122 return klass.getRawTypeAnnotations();
2123 }
2124 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2125 return Class.getExecutableTypeAnnotationBytes(executable);
2126 }
2127 public <E extends Enum<E>>
2128 E[] getEnumConstantsShared(Class<E> klass) {
2129 return klass.getEnumConstantsShared();
2130 }
2131 public void blockedOn(Interruptible b) {
2132 Thread.currentThread().blockedOn(b);
2133 }
2134 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2135 Shutdown.add(slot, registerShutdownInProgress, hook);
2136 }
2137 @SuppressWarnings("removal")
2138 public void invokeFinalize(Object o) throws Throwable {
2139 o.finalize();
2140 }
2141 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2142 return cl.createOrGetClassLoaderValueMap();
2143 }
2144 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2145 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2146 }
2147 public Class<?> defineClass(ClassLoader loader, Class<?> lookup, String name, byte[] b, ProtectionDomain pd,
2148 boolean initialize, int flags, Object classData) {
2149 return ClassLoader.defineClass0(loader, lookup, name, b, 0, b.length, pd, initialize, flags, classData);
2150 }
2151 public Class<?> findBootstrapClassOrNull(String name) {
2152 return ClassLoader.findBootstrapClassOrNull(name);
2153 }
2154 public Package definePackage(ClassLoader cl, String name, Module module) {
2155 return cl.definePackage(name, module);
2156 }
2157 public Module defineModule(ClassLoader loader,
2158 ModuleDescriptor descriptor,
2159 URI uri) {
2160 return new Module(null, loader, descriptor, uri);
2161 }
2162 public Module defineUnnamedModule(ClassLoader loader) {
2163 return new Module(loader);
2164 }
2165 public void addReads(Module m1, Module m2) {
2166 m1.implAddReads(m2);
2167 }
2168 public void addReadsAllUnnamed(Module m) {
2169 m.implAddReadsAllUnnamed();
2170 }
2171 public void addExports(Module m, String pn) {
2172 m.implAddExports(pn);
2173 }
2174 public void addExports(Module m, String pn, Module other) {
2175 m.implAddExports(pn, other);
2176 }
2177 public void addExportsToAllUnnamed(Module m, String pn) {
2178 m.implAddExportsToAllUnnamed(pn);
2179 }
2180 public void addOpens(Module m, String pn, Module other) {
2181 m.implAddOpens(pn, other);
2182 }
2183 public void addOpensToAllUnnamed(Module m, String pn) {
2184 m.implAddOpensToAllUnnamed(pn);
2185 }
2186 public void addOpensToAllUnnamed(Module m, Set<String> concealedPackages, Set<String> exportedPackages) {
2187 m.implAddOpensToAllUnnamed(concealedPackages, exportedPackages);
2188 }
2189 public void addUses(Module m, Class<?> service) {
2190 m.implAddUses(service);
2191 }
2192 public boolean isReflectivelyExported(Module m, String pn, Module other) {
2193 return m.isReflectivelyExported(pn, other);
2194 }
2195 public boolean isReflectivelyOpened(Module m, String pn, Module other) {
2196 return m.isReflectivelyOpened(pn, other);
2197 }
2198 public Module addEnableNativeAccess(Module m) {
2199 return m.implAddEnableNativeAccess();
2200 }
2201 public boolean addEnableNativeAccess(ModuleLayer layer, String name) {
2202 return layer.addEnableNativeAccess(name);
2203 }
2204 public void addEnableNativeAccessToAllUnnamed() {
2205 Module.implAddEnableNativeAccessToAllUnnamed();
2206 }
2207 public void ensureNativeAccess(Module m, Class<?> owner, String methodName, Class<?> currentClass, boolean jni) {
2208 m.ensureNativeAccess(owner, methodName, currentClass, jni);
2209 }
2210 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2211 return layer.getServicesCatalog();
2212 }
2213 public void bindToLoader(ModuleLayer layer, ClassLoader loader) {
2214 layer.bindToLoader(loader);
2215 }
2216 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2217 return layer.layers();
2218 }
2219 public Stream<ModuleLayer> layers(ClassLoader loader) {
2220 return ModuleLayer.layers(loader);
2221 }
2222
2223 public int countPositives(byte[] bytes, int offset, int length) {
2224 return StringCoding.countPositives(bytes, offset, length);
2225 }
2226 public int countNonZeroAscii(String s) {
2227 return StringCoding.countNonZeroAscii(s);
2228 }
2229 public String newStringNoRepl(byte[] bytes, Charset cs) throws CharacterCodingException {
2230 return String.newStringNoRepl(bytes, cs);
2231 }
2232 public char getUTF16Char(byte[] bytes, int index) {
2233 return StringUTF16.getChar(bytes, index);
2234 }
2235 public void putCharUTF16(byte[] bytes, int index, int ch) {
2236 StringUTF16.putChar(bytes, index, ch);
2237 }
2238 public byte[] getBytesNoRepl(String s, Charset cs) throws CharacterCodingException {
2239 return String.getBytesNoRepl(s, cs);
2240 }
2241
2242 public String newStringUTF8NoRepl(byte[] bytes, int off, int len) {
2243 return String.newStringUTF8NoRepl(bytes, off, len, true);
2244 }
2245
2246 public byte[] getBytesUTF8NoRepl(String s) {
2247 return String.getBytesUTF8NoRepl(s);
2248 }
2249
2250 public void inflateBytesToChars(byte[] src, int srcOff, char[] dst, int dstOff, int len) {
2251 StringLatin1.inflate(src, srcOff, dst, dstOff, len);
2252 }
2253
2254 public int decodeASCII(byte[] src, int srcOff, char[] dst, int dstOff, int len) {
2255 return String.decodeASCII(src, srcOff, dst, dstOff, len);
2256 }
2257
2258 public int encodeASCII(char[] src, int srcOff, byte[] dst, int dstOff, int len) {
2259 return StringCoding.implEncodeAsciiArray(src, srcOff, dst, dstOff, len);
2260 }
2261
2262 public InputStream initialSystemIn() {
2263 return initialIn;
2264 }
2265
2266 public PrintStream initialSystemErr() {
2267 return initialErr;
2268 }
2269
2270 public void setCause(Throwable t, Throwable cause) {
2271 t.setCause(cause);
2272 }
2273
2274 public ProtectionDomain protectionDomain(Class<?> c) {
2275 return c.protectionDomain();
2276 }
2277
2278 public MethodHandle stringConcatHelper(String name, MethodType methodType) {
2279 return StringConcatHelper.lookupStatic(name, methodType);
2280 }
2281
2282 public long stringConcatInitialCoder() {
2283 return StringConcatHelper.initialCoder();
2284 }
2285
2286 public long stringConcatMix(long lengthCoder, String constant) {
2287 return StringConcatHelper.mix(lengthCoder, constant);
2288 }
2289
2290 public long stringConcatMix(long lengthCoder, char value) {
2291 return StringConcatHelper.mix(lengthCoder, value);
2292 }
2293
2294 public Object stringConcat1(String[] constants) {
2295 return new StringConcatHelper.Concat1(constants);
2296 }
2297
2298 public byte stringInitCoder() {
2299 return String.COMPACT_STRINGS ? String.LATIN1 : String.UTF16;
2300 }
2301
2302 public byte stringCoder(String str) {
2303 return str.coder();
2304 }
2305
2306 public int getCharsLatin1(long i, int index, byte[] buf) {
2307 return StringLatin1.getChars(i, index, buf);
2308 }
2309
2310 public int getCharsUTF16(long i, int index, byte[] buf) {
2311 return StringUTF16.getChars(i, index, buf);
2312 }
2313
2314 public String join(String prefix, String suffix, String delimiter, String[] elements, int size) {
2315 return String.join(prefix, suffix, delimiter, elements, size);
2316 }
2317
2318 public String concat(String prefix, Object value, String suffix) {
2319 return StringConcatHelper.concat(prefix, value, suffix);
2320 }
2321
2322 public Object classData(Class<?> c) {
2323 return c.getClassData();
2324 }
2325
2326 @Override
2327 public NativeLibraries nativeLibrariesFor(ClassLoader loader) {
2328 return ClassLoader.nativeLibrariesFor(loader);
2329 }
2330
2331 @Override
2332 public void exit(int statusCode) {
2333 Shutdown.exit(statusCode);
2334 }
2335
2336 public Thread[] getAllThreads() {
2337 return Thread.getAllThreads();
2338 }
2339
2340 public ThreadContainer threadContainer(Thread thread) {
2341 return thread.threadContainer();
2342 }
2343
2344 public void start(Thread thread, ThreadContainer container) {
2345 thread.start(container);
2346 }
2347
2348 public StackableScope headStackableScope(Thread thread) {
2349 return thread.headStackableScopes();
2350 }
2351
2352 public void setHeadStackableScope(StackableScope scope) {
2353 Thread.setHeadStackableScope(scope);
2354 }
2355
2356 public Thread currentCarrierThread() {
2357 return Thread.currentCarrierThread();
2358 }
2359
2360 public <T> T getCarrierThreadLocal(CarrierThreadLocal<T> local) {
2361 return ((ThreadLocal<T>)local).getCarrierThreadLocal();
2362 }
2363
2364 public <T> void setCarrierThreadLocal(CarrierThreadLocal<T> local, T value) {
2365 ((ThreadLocal<T>)local).setCarrierThreadLocal(value);
2366 }
2367
2368 public void removeCarrierThreadLocal(CarrierThreadLocal<?> local) {
2369 ((ThreadLocal<?>)local).removeCarrierThreadLocal();
2370 }
2371
2372 public boolean isCarrierThreadLocalPresent(CarrierThreadLocal<?> local) {
2373 return ((ThreadLocal<?>)local).isCarrierThreadLocalPresent();
2374 }
2375
2376 public Object[] scopedValueCache() {
2377 return Thread.scopedValueCache();
2378 }
2379
2380 public void setScopedValueCache(Object[] cache) {
2381 Thread.setScopedValueCache(cache);
2382 }
2383
2384 public Object scopedValueBindings() {
2385 return Thread.scopedValueBindings();
2386 }
2387
2388 public Continuation getContinuation(Thread thread) {
2389 return thread.getContinuation();
2390 }
2391
2392 public void setContinuation(Thread thread, Continuation continuation) {
2393 thread.setContinuation(continuation);
2394 }
2395
2396 public ContinuationScope virtualThreadContinuationScope() {
2397 return VirtualThread.continuationScope();
2398 }
2399
2400 public void parkVirtualThread() {
2401 Thread thread = Thread.currentThread();
2402 if (thread instanceof BaseVirtualThread vthread) {
2403 vthread.park();
2404 } else {
2405 throw new WrongThreadException();
2406 }
2407 }
2408
2409 public void parkVirtualThread(long nanos) {
2410 Thread thread = Thread.currentThread();
2411 if (thread instanceof BaseVirtualThread vthread) {
2412 vthread.parkNanos(nanos);
2413 } else {
2414 throw new WrongThreadException();
2415 }
2416 }
2417
2418 public void unparkVirtualThread(Thread thread) {
2419 if (thread instanceof BaseVirtualThread vthread) {
2420 vthread.unpark();
2421 } else {
2422 throw new WrongThreadException();
2423 }
2424 }
2425
2426 public Executor virtualThreadDefaultScheduler() {
2427 return VirtualThread.defaultScheduler();
2428 }
2429
2430 public Stream<ScheduledExecutorService> virtualThreadDelayedTaskSchedulers() {
2431 return VirtualThread.delayedTaskSchedulers();
2432 }
2433
2434 public StackWalker newStackWalkerInstance(Set<StackWalker.Option> options,
2435 ContinuationScope contScope,
2436 Continuation continuation) {
2437 return StackWalker.newInstance(options, null, contScope, continuation);
2438 }
2439
2440 public String getLoaderNameID(ClassLoader loader) {
2441 return loader != null ? loader.nameAndId() : "null";
2442 }
2443
2444 @Override
2445 public void copyToSegmentRaw(String string, MemorySegment segment, long offset) {
2446 string.copyToSegmentRaw(segment, offset);
2447 }
2448
2449 @Override
2450 public boolean bytesCompatible(String string, Charset charset) {
2451 return string.bytesCompatible(charset);
2452 }
2453 });
2454 }
2455 }