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