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