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.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. This stream
120 * corresponds to keyboard input or another input source specified by
121 * the host environment or user. Applications should use the encoding
122 * specified by the {@link ##stdin.encoding stdin.encoding} property
123 * to convert input bytes to character data.
124 *
125 * @apiNote
126 * The typical approach to read character data is to wrap {@code System.in}
127 * within the object that handles character encoding. After this is done,
128 * subsequent reading should use only the wrapper object; continuing to
129 * operate directly on {@code System.in} results in unspecified behavior.
130 * <p>
131 * Here are two common examples. Using an {@link java.io.InputStreamReader
132 * InputStreamReader}:
133 * {@snippet lang=java :
134 * new InputStreamReader(System.in, System.getProperty("stdin.encoding"));
135 * }
136 * Or using a {@link java.util.Scanner Scanner}:
137 * {@snippet lang=java :
138 * new Scanner(System.in, System.getProperty("stdin.encoding"));
139 * }
140 * <p>
141 * For handling interactive input, consider using {@link Console}.
142 *
143 * @see Console
144 * @see ##stdin.encoding stdin.encoding
145 */
146 public static final InputStream in = null;
147
148 /**
149 * The "standard" output stream. This stream is already
150 * open and ready to accept output data. Typically this stream
151 * corresponds to display output or another output destination
152 * specified by the host environment or user. The encoding used
153 * in the conversion from characters to bytes is equivalent to
154 * {@link ##stdout.encoding stdout.encoding}.
155 * <p>
156 * For simple stand-alone Java applications, a typical way to write
157 * a line of output data is:
158 * <blockquote><pre>
159 * System.out.println(data)
160 * </pre></blockquote>
161 * <p>
162 * See the {@code println} methods in class {@code PrintStream}.
163 *
164 * @see java.io.PrintStream#println()
165 * @see java.io.PrintStream#println(boolean)
166 * @see java.io.PrintStream#println(char)
167 * @see java.io.PrintStream#println(char[])
168 * @see java.io.PrintStream#println(double)
169 * @see java.io.PrintStream#println(float)
170 * @see java.io.PrintStream#println(int)
171 * @see java.io.PrintStream#println(long)
172 * @see java.io.PrintStream#println(java.lang.Object)
173 * @see java.io.PrintStream#println(java.lang.String)
174 * @see ##stdout.encoding stdout.encoding
175 */
176 public static final PrintStream out = null;
177
178 /**
179 * The "standard" error output stream. This stream is already
180 * open and ready to accept output data.
181 * <p>
182 * Typically this stream corresponds to display output or another
183 * output destination specified by the host environment or user. By
184 * convention, this output stream is used to display error messages
185 * or other information that should come to the immediate attention
186 * of a user even if the principal output stream, the value of the
187 * variable {@code out}, has been redirected to a file or other
188 * destination that is typically not continuously monitored.
189 * The encoding used in the conversion from characters to bytes is
190 * equivalent to {@link ##stderr.encoding stderr.encoding}.
191 *
192 * @see ##stderr.encoding stderr.encoding
193 */
194 public static final PrintStream err = null;
195
196 // Initial values of System.in and System.err, set in initPhase1().
197 private static @Stable InputStream initialIn;
198 private static @Stable PrintStream initialErr;
199
200 // `sun.jnu.encoding` if it is not supported. Otherwise null.
201 // It is initialized in `initPhase1()` before any charset providers
202 // are initialized.
203 private static String notSupportedJnuEncoding;
204
205 /**
206 * Reassigns the "standard" input stream.
207 *
208 * @param in the new standard input stream.
209 *
210 * @since 1.1
211 */
212 public static void setIn(InputStream in) {
213 setIn0(in);
214 }
215
216 /**
217 * Reassigns the "standard" output stream.
218 *
219 * @param out the new standard output stream
220 *
221 * @since 1.1
222 */
223 public static void setOut(PrintStream out) {
224 setOut0(out);
225 }
226
227 /**
228 * Reassigns the "standard" error output stream.
229 *
230 * @param err the new standard error output stream.
231 *
232 * @since 1.1
233 */
234 public static void setErr(PrintStream err) {
235 setErr0(err);
236 }
237
238 private static volatile Console cons;
239
240 /**
241 * Returns the unique {@link java.io.Console Console} object associated
242 * with the current Java virtual machine, if any.
243 *
244 * @return The system console, if any, otherwise {@code null}.
245 *
246 * @since 1.6
247 */
248 public static Console console() {
249 Console c;
250 if ((c = cons) == null) {
251 synchronized (System.class) {
252 if ((c = cons) == null) {
253 cons = c = SharedSecrets.getJavaIOAccess().console();
254 }
255 }
256 }
257 return c;
258 }
259
260 /**
261 * Returns the channel inherited from the entity that created this
262 * Java virtual machine.
263 *
264 * This method returns the channel obtained by invoking the
265 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
266 * inheritedChannel} method of the system-wide default
267 * {@link java.nio.channels.spi.SelectorProvider} object.
268 *
269 * <p> In addition to the network-oriented channels described in
270 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
271 * inheritedChannel}, this method may return other kinds of
272 * channels in the future.
273 *
274 * @return The inherited channel, if any, otherwise {@code null}.
275 *
276 * @throws IOException
277 * If an I/O error occurs
278 *
279 * @since 1.5
280 */
281 public static Channel inheritedChannel() throws IOException {
282 return SelectorProvider.provider().inheritedChannel();
283 }
284
285 private static native void setIn0(InputStream in);
286 private static native void setOut0(PrintStream out);
287 private static native void setErr0(PrintStream err);
288
289 /**
290 * Throws {@code UnsupportedOperationException}. Setting a security manager
291 * is not supported.
292 *
293 * @param sm ignored
294 * @throws UnsupportedOperationException always
295 * @see #getSecurityManager
296 * @deprecated This method originally set
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 @Deprecated(since="17", forRemoval=true)
302 public static void setSecurityManager(@SuppressWarnings("removal") SecurityManager sm) {
303 throw new UnsupportedOperationException(
304 "Setting a Security Manager is not supported");
305 }
306
307 /**
308 * Returns {@code null}. Setting a security manager is not supported.
309 *
310 * @return {@code null}
311 * @see #setSecurityManager
312 * @deprecated This method originally returned
313 * {@linkplain SecurityManager the system-wide Security Manager}.
314 * Setting a Security Manager is no longer supported. There is no
315 * replacement for the Security Manager or this method.
316 */
317 @SuppressWarnings("removal")
318 @Deprecated(since="17", forRemoval=true)
319 public static SecurityManager getSecurityManager() {
320 return null;
321 }
322
323 /**
324 * Returns the current time in milliseconds. Note that
325 * while the unit of time of the return value is a millisecond,
326 * the granularity of the value depends on the underlying
327 * operating system and may be larger. For example, many
328 * operating systems measure time in units of tens of
329 * milliseconds.
330 *
331 * <p> See the description of the class {@code Date} for
332 * a discussion of slight discrepancies that may arise between
333 * "computer time" and coordinated universal time (UTC).
334 *
335 * @return the difference, measured in milliseconds, between
336 * the current time and midnight, January 1, 1970 UTC.
337 * @see java.util.Date
338 */
339 @IntrinsicCandidate
340 public static native long currentTimeMillis();
341
342 /**
343 * Returns the current value of the running Java Virtual Machine's
344 * high-resolution time source, in nanoseconds.
345 *
346 * This method can only be used to measure elapsed time and is
347 * not related to any other notion of system or wall-clock time.
348 * The value returned represents nanoseconds since some fixed but
349 * arbitrary <i>origin</i> time (perhaps in the future, so values
350 * may be negative). The same origin is used by all invocations of
351 * this method in an instance of a Java virtual machine; other
352 * virtual machine instances are likely to use a different origin.
353 *
354 * <p>This method provides nanosecond precision, but not necessarily
355 * nanosecond resolution (that is, how frequently the value changes)
356 * - no guarantees are made except that the resolution is at least as
357 * good as that of {@link #currentTimeMillis()}.
358 *
359 * <p>Differences in successive calls that span greater than
360 * approximately 292 years (2<sup>63</sup> nanoseconds) will not
361 * correctly compute elapsed time due to numerical overflow.
362 *
363 * <p>The values returned by this method become meaningful only when
364 * the difference between two such values, obtained within the same
365 * instance of a Java virtual machine, is computed.
366 *
367 * <p>For example, to measure how long some code takes to execute:
368 * <pre> {@code
369 * long startTime = System.nanoTime();
370 * // ... the code being measured ...
371 * long elapsedNanos = System.nanoTime() - startTime;}</pre>
372 *
373 * <p>To compare elapsed time against a timeout, use <pre> {@code
374 * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
375 * instead of <pre> {@code
376 * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
377 * because of the possibility of numerical overflow.
378 *
379 * @return the current value of the running Java Virtual Machine's
380 * high-resolution time source, in nanoseconds
381 * @since 1.5
382 */
383 @IntrinsicCandidate
384 public static native long nanoTime();
385
386 /**
387 * Copies an array from the specified source array, beginning at the
388 * specified position, to the specified position of the destination array.
389 * A subsequence of array components are copied from the source
390 * array referenced by {@code src} to the destination array
391 * referenced by {@code dest}. The number of components copied is
392 * equal to the {@code length} argument. The components at
393 * positions {@code srcPos} through
394 * {@code srcPos+length-1} in the source array are copied into
395 * positions {@code destPos} through
396 * {@code destPos+length-1}, respectively, of the destination
397 * array.
398 * <p>
399 * If the {@code src} and {@code dest} arguments refer to the
400 * same array object, then the copying is performed as if the
401 * components at positions {@code srcPos} through
402 * {@code srcPos+length-1} were first copied to a temporary
403 * array with {@code length} components and then the contents of
404 * the temporary array were copied into positions
405 * {@code destPos} through {@code destPos+length-1} of the
406 * destination array.
407 * <p>
408 * If {@code dest} is {@code null}, then a
409 * {@code NullPointerException} is thrown.
410 * <p>
411 * If {@code src} is {@code null}, then a
412 * {@code NullPointerException} is thrown and the destination
413 * array is not modified.
414 * <p>
415 * Otherwise, if any of the following is true, an
416 * {@code ArrayStoreException} is thrown and the destination is
417 * not modified:
418 * <ul>
419 * <li>The {@code src} argument refers to an object that is not an
420 * array.
421 * <li>The {@code dest} argument refers to an object that is not an
422 * array.
423 * <li>The {@code src} argument and {@code dest} argument refer
424 * to arrays whose component types are different primitive types.
425 * <li>The {@code src} argument refers to an array with a primitive
426 * component type and the {@code dest} argument refers to an array
427 * with a reference component type.
428 * <li>The {@code src} argument refers to an array with a reference
429 * component type and the {@code dest} argument refers to an array
430 * with a primitive component type.
431 * </ul>
432 * <p>
433 * Otherwise, if any of the following is true, an
434 * {@code IndexOutOfBoundsException} is
435 * thrown and the destination is not modified:
436 * <ul>
437 * <li>The {@code srcPos} argument is negative.
438 * <li>The {@code destPos} argument is negative.
439 * <li>The {@code length} argument is negative.
440 * <li>{@code srcPos+length} is greater than
441 * {@code src.length}, the length of the source array.
442 * <li>{@code destPos+length} is greater than
443 * {@code dest.length}, the length of the destination array.
444 * </ul>
445 * <p>
446 * Otherwise, if any actual component of the source array from
447 * position {@code srcPos} through
448 * {@code srcPos+length-1} cannot be converted to the component
449 * type of the destination array by assignment conversion, an
450 * {@code ArrayStoreException} is thrown. In this case, let
451 * <b><i>k</i></b> be the smallest nonnegative integer less than
452 * length such that {@code src[srcPos+}<i>k</i>{@code ]}
453 * cannot be converted to the component type of the destination
454 * array; when the exception is thrown, source array components from
455 * positions {@code srcPos} through
456 * {@code srcPos+}<i>k</i>{@code -1}
457 * will already have been copied to destination array positions
458 * {@code destPos} through
459 * {@code destPos+}<i>k</I>{@code -1} and no other
460 * positions of the destination array will have been modified.
461 * (Because of the restrictions already itemized, this
462 * paragraph effectively applies only to the situation where both
463 * arrays have component types that are reference types.)
464 *
465 * @param src the source array.
466 * @param srcPos starting position in the source array.
467 * @param dest the destination array.
468 * @param destPos starting position in the destination data.
469 * @param length the number of array elements to be copied.
470 * @throws IndexOutOfBoundsException if copying would cause
471 * access of data outside array bounds.
472 * @throws ArrayStoreException if an element in the {@code src}
473 * array could not be stored into the {@code dest} array
474 * because of a type mismatch.
475 * @throws NullPointerException if either {@code src} or
476 * {@code dest} is {@code null}.
477 */
478 @IntrinsicCandidate
479 public static native void arraycopy(Object src, int srcPos,
480 Object dest, int destPos,
481 int length);
482
483 /**
484 * Returns the same hash code for the given object as
485 * would be returned by the default method hashCode(),
486 * whether or not the given object's class overrides
487 * hashCode().
488 * The hash code for the null reference is zero.
489 *
490 * <div class="preview-block">
491 * <div class="preview-comment">
492 * The "identity hash code" of a {@linkplain Class#isValue() value object}
493 * is computed by combining the identity hash codes of the value object's fields recursively.
494 * </div>
495 * </div>
496 * @apiNote
497 * <div class="preview-block">
498 * <div class="preview-comment">
499 * Note that, like ==, this hash code exposes information about a value object's
500 * private fields that might otherwise be hidden by an identity object.
501 * Developers should be cautious about storing sensitive secrets in value object fields.
502 * </div>
503 * </div>
504 *
505 * @param x object for which the hashCode is to be calculated
506 * @return the hashCode
507 * @since 1.1
508 * @see Object#hashCode
509 * @see java.util.Objects#hashCode(Object)
510 */
511 @IntrinsicCandidate
512 public static native int identityHashCode(Object x);
513
514 /**
515 * System properties.
516 *
517 * See {@linkplain #getProperties getProperties} for details.
518 */
519 private static Properties props;
520
521 /**
522 * Determines the current system properties.
523 * <p>
524 * The current set of system properties for use by the
525 * {@link #getProperty(String)} method is returned as a
526 * {@code Properties} object. If there is no current set of
527 * system properties, a set of system properties is first created and
528 * initialized. This set of system properties includes a value
529 * for each of the following keys unless the description of the associated
530 * value indicates that the value is optional.
531 * <table class="striped" style="text-align:left">
532 * <caption style="display:none">Shows property keys and associated values</caption>
533 * <thead>
534 * <tr><th scope="col">Key</th>
535 * <th scope="col">Description of Associated Value</th></tr>
536 * </thead>
537 * <tbody>
538 * <tr><th scope="row">{@systemProperty java.version}</th>
539 * <td>Java Runtime Environment version, which may be interpreted
540 * as a {@link Runtime.Version}</td></tr>
541 * <tr><th scope="row">{@systemProperty java.version.date}</th>
542 * <td>Java Runtime Environment version date, in ISO-8601 YYYY-MM-DD
543 * format, which may be interpreted as a {@link
544 * java.time.LocalDate}</td></tr>
545 * <tr><th scope="row">{@systemProperty java.vendor}</th>
546 * <td>Java Runtime Environment vendor</td></tr>
547 * <tr><th scope="row">{@systemProperty java.vendor.url}</th>
548 * <td>Java vendor URL</td></tr>
549 * <tr><th scope="row">{@systemProperty java.vendor.version}</th>
550 * <td>Java vendor version <em>(optional)</em> </td></tr>
551 * <tr><th scope="row">{@systemProperty java.home}</th>
552 * <td>Java installation directory</td></tr>
553 * <tr><th scope="row">{@systemProperty java.vm.specification.version}</th>
554 * <td>Java Virtual Machine specification version, whose value is the
555 * {@linkplain Runtime.Version#feature feature} element of the
556 * {@linkplain Runtime#version() runtime version}</td></tr>
557 * <tr><th scope="row">{@systemProperty java.vm.specification.vendor}</th>
558 * <td>Java Virtual Machine specification vendor</td></tr>
559 * <tr><th scope="row">{@systemProperty java.vm.specification.name}</th>
560 * <td>Java Virtual Machine specification name</td></tr>
561 * <tr><th scope="row">{@systemProperty java.vm.version}</th>
562 * <td>Java Virtual Machine implementation version which may be
563 * interpreted as a {@link Runtime.Version}</td></tr>
564 * <tr><th scope="row">{@systemProperty java.vm.vendor}</th>
565 * <td>Java Virtual Machine implementation vendor</td></tr>
566 * <tr><th scope="row">{@systemProperty java.vm.name}</th>
567 * <td>Java Virtual Machine implementation name</td></tr>
568 * <tr><th scope="row">{@systemProperty java.specification.version}</th>
569 * <td>Java Runtime Environment specification version, whose value is
570 * the {@linkplain Runtime.Version#feature feature} element of the
571 * {@linkplain Runtime#version() runtime version}</td></tr>
572 * <tr><th scope="row">{@systemProperty java.specification.maintenance.version}</th>
573 * <td>Java Runtime Environment specification maintenance version,
574 * may be interpreted as a positive integer <em>(optional, see below)</em></td></tr>
575 * <tr><th scope="row">{@systemProperty java.specification.vendor}</th>
576 * <td>Java Runtime Environment specification vendor</td></tr>
577 * <tr><th scope="row">{@systemProperty java.specification.name}</th>
578 * <td>Java Runtime Environment specification name</td></tr>
579 * <tr><th scope="row">{@systemProperty java.class.version}</th>
580 * <td>{@linkplain java.lang.reflect.ClassFileFormatVersion#latest() Latest}
581 * Java class file format version recognized by the Java runtime as {@code "MAJOR.MINOR"}
582 * where {@link java.lang.reflect.ClassFileFormatVersion#major() MAJOR} and {@code MINOR}
583 * are both formatted as decimal integers</td></tr>
584 * <tr><th scope="row">{@systemProperty java.class.path}</th>
585 * <td>Java class path (refer to
586 * {@link ClassLoader#getSystemClassLoader()} for details)</td></tr>
587 * <tr><th scope="row">{@systemProperty java.library.path}</th>
588 * <td>List of paths to search when loading libraries</td></tr>
589 * <tr><th scope="row">{@systemProperty java.io.tmpdir}</th>
590 * <td>Default temp file path</td></tr>
591 * <tr><th scope="row">{@systemProperty os.name}</th>
592 * <td>Operating system name</td></tr>
593 * <tr><th scope="row">{@systemProperty os.arch}</th>
594 * <td>Operating system architecture</td></tr>
595 * <tr><th scope="row">{@systemProperty os.version}</th>
596 * <td>Operating system version</td></tr>
597 * <tr><th scope="row">{@systemProperty file.separator}</th>
598 * <td>File separator ("/" on UNIX)</td></tr>
599 * <tr><th scope="row">{@systemProperty path.separator}</th>
600 * <td>Path separator (":" on UNIX)</td></tr>
601 * <tr><th scope="row">{@systemProperty line.separator}</th>
602 * <td>Line separator ("\n" on UNIX)</td></tr>
603 * <tr><th scope="row">{@systemProperty user.name}</th>
604 * <td>User's account name</td></tr>
605 * <tr><th scope="row">{@systemProperty user.home}</th>
606 * <td>User's home directory</td></tr>
607 * <tr><th scope="row">{@systemProperty user.dir}</th>
608 * <td>User's current working directory</td></tr>
609 * <tr><th scope="row">{@systemProperty native.encoding}</th>
610 * <td>Character encoding name derived from the host environment and
611 * the user's settings. Setting this system property on the command line
612 * has no effect.</td></tr>
613 * <tr><th scope="row">{@systemProperty stdin.encoding}</th>
614 * <td>Character encoding name for {@link System#in System.in}.
615 * The Java runtime can be started with the system property set to {@code UTF-8}.
616 * Starting it with the property set to another value results in unspecified behavior.
617 * <tr><th scope="row">{@systemProperty stdout.encoding}</th>
618 * <td>Character encoding name for {@link System#out System.out} and
619 * {@link System#console() System.console()}.
620 * The Java runtime can be started with the system property set to {@code UTF-8}.
621 * Starting it with the property set to another value results in unspecified behavior.
622 * <tr><th scope="row">{@systemProperty stderr.encoding}</th>
623 * <td>Character encoding name for {@link System#err System.err}.
624 * The Java runtime can be started with the system property set to {@code UTF-8}.
625 * Starting it with the property set to another value results in unspecified behavior.
626 * </tbody>
627 * </table>
628 * <p>
629 * The {@code java.specification.maintenance.version} property is
630 * defined if the specification implemented by this runtime at the
631 * time of its construction had undergone a <a
632 * href="https://jcp.org/en/procedures/jcp2#3.6.4">maintenance
633 * release</a>. When defined, its value identifies that
634 * maintenance release. To indicate the first maintenance release
635 * this property will have the value {@code "1"}, to indicate the
636 * second maintenance release this property will have the value
637 * {@code "2"}, and so on.
638 * <p>
639 * Multiple paths in a system property value are separated by the path
640 * separator character of the platform.
641 * <p>
642 * Additional locale-related system properties defined by the
643 * {@link Locale##default_locale Default Locale} section in the {@code Locale}
644 * class description may also be obtained with this method.
645 *
646 * @apiNote
647 * <strong>Changing a standard system property may have unpredictable results
648 * unless otherwise specified.</strong>
649 * Property values may be cached during initialization or on first use.
650 * Setting a standard property after initialization using {@link #getProperties()},
651 * {@link #setProperties(Properties)}, {@link #setProperty(String, String)}, or
652 * {@link #clearProperty(String)} may not have the desired effect.
653 *
654 * @implNote
655 * In addition to the standard system properties, the system
656 * properties may include the following keys:
657 * <table class="striped">
658 * <caption style="display:none">Shows property keys and associated values</caption>
659 * <thead>
660 * <tr><th scope="col">Key</th>
661 * <th scope="col">Description of Associated Value</th></tr>
662 * </thead>
663 * <tbody>
664 * <tr><th scope="row">{@systemProperty jdk.module.path}</th>
665 * <td>The application module path</td></tr>
666 * <tr><th scope="row">{@systemProperty jdk.module.upgrade.path}</th>
667 * <td>The upgrade module path</td></tr>
668 * <tr><th scope="row">{@systemProperty jdk.module.main}</th>
669 * <td>The module name of the initial/main module</td></tr>
670 * <tr><th scope="row">{@systemProperty jdk.module.main.class}</th>
671 * <td>The main class name of the initial module</td></tr>
672 * <tr><th scope="row">{@systemProperty file.encoding}</th>
673 * <td>The name of the default charset, defaults to {@code UTF-8}.
674 * The property may be set on the command line to the value
675 * {@code UTF-8} or {@code COMPAT}. If set on the command line to
676 * the value {@code COMPAT} then the value is replaced with the
677 * value of the {@code native.encoding} property during startup.
678 * Setting the property to a value other than {@code UTF-8} or
679 * {@code COMPAT} results in unspecified behavior.
680 * </td></tr>
681 * </tbody>
682 * </table>
683 *
684 * @return the system properties
685 * @see #setProperties
686 * @see java.util.Properties
687 */
688 public static Properties getProperties() {
689 return props;
690 }
691
692 /**
693 * Returns the system-dependent line separator string. It always
694 * returns the same value - the initial value of the {@linkplain
695 * #getProperty(String) system property} {@code line.separator}.
696 *
697 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
698 * Windows systems it returns {@code "\r\n"}.
699 *
700 * @return the system-dependent line separator string
701 * @since 1.7
702 */
703 public static String lineSeparator() {
704 return lineSeparator;
705 }
706
707 private static String lineSeparator;
708
709 /**
710 * Sets the system properties to the {@code Properties} argument.
711 * <p>
712 * The argument becomes the current set of system properties for use
713 * by the {@link #getProperty(String)} method. If the argument is
714 * {@code null}, then the current set of system properties is
715 * forgotten.
716 *
717 * @apiNote
718 * <strong>Changing a standard system property may have unpredictable results
719 * unless otherwise specified</strong>.
720 * See {@linkplain #getProperties getProperties} for details.
721 *
722 * @param props the new system properties.
723 * @see #getProperties
724 * @see java.util.Properties
725 */
726 public static void setProperties(Properties props) {
727 if (props == null) {
728 Map<String, String> tempProps = SystemProps.initProperties();
729 VersionProps.init(tempProps);
730 props = createProperties(tempProps);
731 }
732 System.props = props;
733 }
734
735 /**
736 * Gets the system property indicated by the specified key.
737 * <p>
738 * If there is no current set of system properties, a set of system
739 * properties is first created and initialized in the same manner as
740 * for the {@code getProperties} method.
741 *
742 * @apiNote
743 * <strong>Changing a standard system property may have unpredictable results
744 * unless otherwise specified</strong>.
745 * See {@linkplain #getProperties getProperties} for details.
746 *
747 * @param key the name of the system property.
748 * @return the string value of the system property,
749 * or {@code null} if there is no property with that key.
750 *
751 * @throws NullPointerException if {@code key} is {@code null}.
752 * @throws IllegalArgumentException if {@code key} is empty.
753 * @see #setProperty
754 * @see java.lang.System#getProperties()
755 */
756 public static String getProperty(String key) {
757 checkKey(key);
758 return props.getProperty(key);
759 }
760
761 /**
762 * Gets the system property indicated by the specified key.
763 * <p>
764 * If there is no current set of system properties, a set of system
765 * properties is first created and initialized in the same manner as
766 * for the {@code getProperties} method.
767 *
768 * @param key the name of the system property.
769 * @param def a default value.
770 * @return the string value of the system property,
771 * or the default value if there is no property with that key.
772 *
773 * @throws NullPointerException if {@code key} is {@code null}.
774 * @throws IllegalArgumentException if {@code key} is empty.
775 * @see #setProperty
776 * @see java.lang.System#getProperties()
777 */
778 public static String getProperty(String key, String def) {
779 checkKey(key);
780 return props.getProperty(key, def);
781 }
782
783 /**
784 * Sets the system property indicated by the specified key.
785 *
786 * @apiNote
787 * <strong>Changing a standard system property may have unpredictable results
788 * unless otherwise specified</strong>.
789 * See {@linkplain #getProperties getProperties} for details.
790 *
791 * @param key the name of the system property.
792 * @param value the value of the system property.
793 * @return the previous value of the system property,
794 * or {@code null} if it did not have one.
795 *
796 * @throws NullPointerException if {@code key} or
797 * {@code value} is {@code null}.
798 * @throws IllegalArgumentException if {@code key} is empty.
799 * @see #getProperty
800 * @see java.lang.System#getProperty(java.lang.String)
801 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
802 * @since 1.2
803 */
804 public static String setProperty(String key, String value) {
805 checkKey(key);
806 return (String) props.setProperty(key, value);
807 }
808
809 /**
810 * Removes the system property indicated by the specified key.
811 *
812 * @apiNote
813 * <strong>Changing a standard system property may have unpredictable results
814 * unless otherwise specified</strong>.
815 * See {@linkplain #getProperties getProperties} method for details.
816 *
817 * @param key the name of the system property to be removed.
818 * @return the previous string value of the system property,
819 * or {@code null} if there was no property with that key.
820 *
821 * @throws NullPointerException if {@code key} is {@code null}.
822 * @throws IllegalArgumentException if {@code key} is empty.
823 * @see #getProperty
824 * @see #setProperty
825 * @see java.util.Properties
826 * @since 1.5
827 */
828 public static String clearProperty(String key) {
829 checkKey(key);
830 return (String) props.remove(key);
831 }
832
833 private static void checkKey(String key) {
834 if (key == null) {
835 throw new NullPointerException("key can't be null");
836 }
837 if (key.isEmpty()) {
838 throw new IllegalArgumentException("key can't be empty");
839 }
840 }
841
842 /**
843 * Gets the value of the specified environment variable. An
844 * environment variable is a system-dependent external named
845 * value.
846 *
847 * <p><a id="EnvironmentVSSystemProperties"><i>System
848 * properties</i> and <i>environment variables</i></a> are both
849 * conceptually mappings between names and values. Both
850 * mechanisms can be used to pass user-defined information to a
851 * Java process. Environment variables have a more global effect,
852 * because they are visible to all descendants of the process
853 * which defines them, not just the immediate Java subprocess.
854 * They can have subtly different semantics, such as case
855 * insensitivity, on different operating systems. For these
856 * reasons, environment variables are more likely to have
857 * unintended side effects. It is best to use system properties
858 * where possible. Environment variables should be used when a
859 * global effect is desired, or when an external system interface
860 * requires an environment variable (such as {@code PATH}).
861 *
862 * <p>On UNIX systems the alphabetic case of {@code name} is
863 * typically significant, while on Microsoft Windows systems it is
864 * typically not. For example, the expression
865 * {@code System.getenv("FOO").equals(System.getenv("foo"))}
866 * is likely to be true on Microsoft Windows.
867 *
868 * @param name the name of the environment variable
869 * @return the string value of the variable, or {@code null}
870 * if the variable is not defined in the system environment
871 * @throws NullPointerException if {@code name} is {@code null}
872 * @see #getenv()
873 * @see ProcessBuilder#environment()
874 */
875 public static String getenv(String name) {
876 return ProcessEnvironment.getenv(name);
877 }
878
879
880 /**
881 * Returns an unmodifiable string map view of the current system environment.
882 * The environment is a system-dependent mapping from names to
883 * values which is passed from parent to child processes.
884 *
885 * <p>If the system does not support environment variables, an
886 * empty map is returned.
887 *
888 * <p>The returned map will never contain null keys or values.
889 * Attempting to query the presence of a null key or value will
890 * throw a {@link NullPointerException}. Attempting to query
891 * the presence of a key or value which is not of type
892 * {@link String} will throw a {@link ClassCastException}.
893 *
894 * <p>The returned map and its collection views may not obey the
895 * general contract of the {@link Object#equals} and
896 * {@link Object#hashCode} methods.
897 *
898 * <p>The returned map is typically case-sensitive on all platforms.
899 *
900 * <p>When passing information to a Java subprocess,
901 * <a href=#EnvironmentVSSystemProperties>system properties</a>
902 * are generally preferred over environment variables.
903 *
904 * @return the environment as a map of variable names to values
905 * @see #getenv(String)
906 * @see ProcessBuilder#environment()
907 * @since 1.5
908 */
909 public static java.util.Map<String,String> getenv() {
910 return ProcessEnvironment.getenv();
911 }
912
913 /**
914 * {@code System.Logger} instances log messages that will be
915 * routed to the underlying logging framework the {@link System.LoggerFinder
916 * LoggerFinder} uses.
917 *
918 * {@code System.Logger} instances are typically obtained from
919 * the {@link java.lang.System System} class, by calling
920 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
921 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
922 * System.getLogger(loggerName, bundle)}.
923 *
924 * @see java.lang.System#getLogger(java.lang.String)
925 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
926 * @see java.lang.System.LoggerFinder
927 *
928 * @since 9
929 */
930 public interface Logger {
931
932 /**
933 * System {@linkplain Logger loggers} levels.
934 *
935 * A level has a {@linkplain #getName() name} and {@linkplain
936 * #getSeverity() severity}.
937 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
938 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
939 * by order of increasing severity.
940 * <br>
941 * {@link #ALL} and {@link #OFF}
942 * are simple markers with severities mapped respectively to
943 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
944 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
945 * <p>
946 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
947 * <p>
948 * {@linkplain System.Logger.Level System logger levels} are mapped to
949 * {@linkplain java.logging/java.util.logging.Level java.util.logging levels}
950 * of corresponding severity.
951 * <br>The mapping is as follows:
952 * <br><br>
953 * <table class="striped">
954 * <caption>System.Logger Severity Level Mapping</caption>
955 * <thead>
956 * <tr><th scope="col">System.Logger Levels</th>
957 * <th scope="col">java.util.logging Levels</th>
958 * </thead>
959 * <tbody>
960 * <tr><th scope="row">{@link Logger.Level#ALL ALL}</th>
961 * <td>{@link java.logging/java.util.logging.Level#ALL ALL}</td>
962 * <tr><th scope="row">{@link Logger.Level#TRACE TRACE}</th>
963 * <td>{@link java.logging/java.util.logging.Level#FINER FINER}</td>
964 * <tr><th scope="row">{@link Logger.Level#DEBUG DEBUG}</th>
965 * <td>{@link java.logging/java.util.logging.Level#FINE FINE}</td>
966 * <tr><th scope="row">{@link Logger.Level#INFO INFO}</th>
967 * <td>{@link java.logging/java.util.logging.Level#INFO INFO}</td>
968 * <tr><th scope="row">{@link Logger.Level#WARNING WARNING}</th>
969 * <td>{@link java.logging/java.util.logging.Level#WARNING WARNING}</td>
970 * <tr><th scope="row">{@link Logger.Level#ERROR ERROR}</th>
971 * <td>{@link java.logging/java.util.logging.Level#SEVERE SEVERE}</td>
972 * <tr><th scope="row">{@link Logger.Level#OFF OFF}</th>
973 * <td>{@link java.logging/java.util.logging.Level#OFF OFF}</td>
974 * </tbody>
975 * </table>
976 *
977 * @since 9
978 *
979 * @see java.lang.System.LoggerFinder
980 * @see java.lang.System.Logger
981 */
982 @SuppressWarnings("doclint:reference") // cross-module links
983 public enum Level {
984
985 // for convenience, we're reusing java.util.logging.Level int values
986 // the mapping logic in sun.util.logging.PlatformLogger depends
987 // on this.
988 /**
989 * A marker to indicate that all levels are enabled.
990 * This level {@linkplain #getSeverity() severity} is
991 * {@link Integer#MIN_VALUE}.
992 */
993 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
994 /**
995 * {@code TRACE} level: usually used to log diagnostic information.
996 * This level {@linkplain #getSeverity() severity} is
997 * {@code 400}.
998 */
999 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1000 /**
1001 * {@code DEBUG} level: usually used to log debug information traces.
1002 * This level {@linkplain #getSeverity() severity} is
1003 * {@code 500}.
1004 */
1005 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1006 /**
1007 * {@code INFO} level: usually used to log information messages.
1008 * This level {@linkplain #getSeverity() severity} is
1009 * {@code 800}.
1010 */
1011 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1012 /**
1013 * {@code WARNING} level: usually used to log warning messages.
1014 * This level {@linkplain #getSeverity() severity} is
1015 * {@code 900}.
1016 */
1017 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1018 /**
1019 * {@code ERROR} level: usually used to log error messages.
1020 * This level {@linkplain #getSeverity() severity} is
1021 * {@code 1000}.
1022 */
1023 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1024 /**
1025 * A marker to indicate that all levels are disabled.
1026 * This level {@linkplain #getSeverity() severity} is
1027 * {@link Integer#MAX_VALUE}.
1028 */
1029 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1030
1031 private final int severity;
1032
1033 private Level(int severity) {
1034 this.severity = severity;
1035 }
1036
1037 /**
1038 * Returns the name of this level.
1039 * @return this level {@linkplain #name()}.
1040 */
1041 public final String getName() {
1042 return name();
1043 }
1044
1045 /**
1046 * Returns the severity of this level.
1047 * A higher severity means a more severe condition.
1048 * @return this level severity.
1049 */
1050 public final int getSeverity() {
1051 return severity;
1052 }
1053 }
1054
1055 /**
1056 * Returns the name of this logger.
1057 *
1058 * @return the logger name.
1059 */
1060 public String getName();
1061
1062 /**
1063 * Checks if a message of the given level would be logged by
1064 * this logger.
1065 *
1066 * @param level the log message level.
1067 * @return {@code true} if the given log message level is currently
1068 * being logged.
1069 *
1070 * @throws NullPointerException if {@code level} is {@code null}.
1071 */
1072 public boolean isLoggable(Level level);
1073
1074 /**
1075 * Logs a message.
1076 *
1077 * @implSpec The default implementation for this method calls
1078 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1079 *
1080 * @param level the log message level.
1081 * @param msg the string message (or a key in the message catalog, if
1082 * this logger is a {@link
1083 * LoggerFinder#getLocalizedLogger(java.lang.String,
1084 * java.util.ResourceBundle, java.lang.Module) localized logger});
1085 * can be {@code null}.
1086 *
1087 * @throws NullPointerException if {@code level} is {@code null}.
1088 */
1089 public default void log(Level level, String msg) {
1090 log(level, (ResourceBundle) null, msg, (Object[]) null);
1091 }
1092
1093 /**
1094 * Logs a lazily supplied message.
1095 *
1096 * If the logger is currently enabled for the given log message level
1097 * then a message is logged that is the result produced by the
1098 * given supplier function. Otherwise, the supplier is not operated on.
1099 *
1100 * @implSpec When logging is enabled for the given level, the default
1101 * implementation for this method calls
1102 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1103 *
1104 * @param level the log message level.
1105 * @param msgSupplier a supplier function that produces a message.
1106 *
1107 * @throws NullPointerException if {@code level} is {@code null},
1108 * or {@code msgSupplier} is {@code null}.
1109 */
1110 public default void log(Level level, Supplier<String> msgSupplier) {
1111 Objects.requireNonNull(msgSupplier);
1112 if (isLoggable(Objects.requireNonNull(level))) {
1113 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1114 }
1115 }
1116
1117 /**
1118 * Logs a message produced from the given object.
1119 *
1120 * If the logger is currently enabled for the given log message level then
1121 * a message is logged that, by default, is the result produced from
1122 * calling toString on the given object.
1123 * Otherwise, the object is not operated on.
1124 *
1125 * @implSpec When logging is enabled for the given level, the default
1126 * implementation for this method calls
1127 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1128 *
1129 * @param level the log message level.
1130 * @param obj the object to log.
1131 *
1132 * @throws NullPointerException if {@code level} is {@code null}, or
1133 * {@code obj} is {@code null}.
1134 */
1135 public default void log(Level level, Object obj) {
1136 Objects.requireNonNull(obj);
1137 if (isLoggable(Objects.requireNonNull(level))) {
1138 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1139 }
1140 }
1141
1142 /**
1143 * Logs a message associated with a given throwable.
1144 *
1145 * @implSpec The default implementation for this method calls
1146 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1147 *
1148 * @param level the log message level.
1149 * @param msg the string message (or a key in the message catalog, if
1150 * this logger is a {@link
1151 * LoggerFinder#getLocalizedLogger(java.lang.String,
1152 * java.util.ResourceBundle, java.lang.Module) localized logger});
1153 * can be {@code null}.
1154 * @param thrown a {@code Throwable} associated with the log message;
1155 * can be {@code null}.
1156 *
1157 * @throws NullPointerException if {@code level} is {@code null}.
1158 */
1159 public default void log(Level level, String msg, Throwable thrown) {
1160 this.log(level, null, msg, thrown);
1161 }
1162
1163 /**
1164 * Logs a lazily supplied message associated with a given throwable.
1165 *
1166 * If the logger is currently enabled for the given log message level
1167 * then a message is logged that is the result produced by the
1168 * given supplier function. Otherwise, the supplier is not operated on.
1169 *
1170 * @implSpec When logging is enabled for the given level, the default
1171 * implementation for this method calls
1172 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1173 *
1174 * @param level one of the log message level identifiers.
1175 * @param msgSupplier a supplier function that produces a message.
1176 * @param thrown a {@code Throwable} associated with log message;
1177 * can be {@code null}.
1178 *
1179 * @throws NullPointerException if {@code level} is {@code null}, or
1180 * {@code msgSupplier} is {@code null}.
1181 */
1182 public default void log(Level level, Supplier<String> msgSupplier,
1183 Throwable thrown) {
1184 Objects.requireNonNull(msgSupplier);
1185 if (isLoggable(Objects.requireNonNull(level))) {
1186 this.log(level, null, msgSupplier.get(), thrown);
1187 }
1188 }
1189
1190 /**
1191 * Logs a message with an optional list of parameters.
1192 *
1193 * @implSpec The default implementation for this method calls
1194 * {@code this.log(level, (ResourceBundle)null, format, params);}
1195 *
1196 * @param level one of the log message level identifiers.
1197 * @param format the string message format in {@link
1198 * java.text.MessageFormat} format, (or a key in the message
1199 * catalog, if this logger is a {@link
1200 * LoggerFinder#getLocalizedLogger(java.lang.String,
1201 * java.util.ResourceBundle, java.lang.Module) localized logger});
1202 * can be {@code null}.
1203 * @param params an optional list of parameters to the message (may be
1204 * none).
1205 *
1206 * @throws NullPointerException if {@code level} is {@code null}.
1207 */
1208 public default void log(Level level, String format, Object... params) {
1209 this.log(level, null, format, params);
1210 }
1211
1212 /**
1213 * Logs a localized message associated with a given throwable.
1214 *
1215 * If the given resource bundle is non-{@code null}, the {@code msg}
1216 * string is localized using the given resource bundle.
1217 * Otherwise the {@code msg} string is not localized.
1218 *
1219 * @param level the log message level.
1220 * @param bundle a resource bundle to localize {@code msg}; can be
1221 * {@code null}.
1222 * @param msg the string message (or a key in the message catalog,
1223 * if {@code bundle} is not {@code null}); can be {@code null}.
1224 * @param thrown a {@code Throwable} associated with the log message;
1225 * can be {@code null}.
1226 *
1227 * @throws NullPointerException if {@code level} is {@code null}.
1228 */
1229 public void log(Level level, ResourceBundle bundle, String msg,
1230 Throwable thrown);
1231
1232 /**
1233 * Logs a message with resource bundle and an optional list of
1234 * parameters.
1235 *
1236 * If the given resource bundle is non-{@code null}, the {@code format}
1237 * string is localized using the given resource bundle.
1238 * Otherwise the {@code format} string is not localized.
1239 *
1240 * @param level the log message level.
1241 * @param bundle a resource bundle to localize {@code format}; can be
1242 * {@code null}.
1243 * @param format the string message format in {@link
1244 * java.text.MessageFormat} format, (or a key in the message
1245 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1246 * @param params an optional list of parameters to the message (may be
1247 * none).
1248 *
1249 * @throws NullPointerException if {@code level} is {@code null}.
1250 */
1251 public void log(Level level, ResourceBundle bundle, String format,
1252 Object... params);
1253 }
1254
1255 /**
1256 * The {@code LoggerFinder} service is responsible for creating, managing,
1257 * and configuring loggers to the underlying framework it uses.
1258 *
1259 * A logger finder is a concrete implementation of this class that has a
1260 * zero-argument constructor and implements the abstract methods defined
1261 * by this class.
1262 * The loggers returned from a logger finder are capable of routing log
1263 * messages to the logging backend this provider supports.
1264 * A given invocation of the Java Runtime maintains a single
1265 * system-wide LoggerFinder instance that is loaded as follows:
1266 * <ul>
1267 * <li>First it finds any custom {@code LoggerFinder} provider
1268 * using the {@link java.util.ServiceLoader} facility with the
1269 * {@linkplain ClassLoader#getSystemClassLoader() system class
1270 * loader}.</li>
1271 * <li>If no {@code LoggerFinder} provider is found, the system default
1272 * {@code LoggerFinder} implementation will be used.</li>
1273 * </ul>
1274 * <p>
1275 * An application can replace the logging backend
1276 * <i>even when the java.logging module is present</i>, by simply providing
1277 * and declaring an implementation of the {@link LoggerFinder} service.
1278 * <p>
1279 * <b>Default Implementation</b>
1280 * <p>
1281 * The system default {@code LoggerFinder} implementation uses
1282 * {@code java.util.logging} as the backend framework when the
1283 * {@code java.logging} module is present.
1284 * It returns a {@linkplain System.Logger logger} instance
1285 * that will route log messages to a {@link java.logging/java.util.logging.Logger
1286 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1287 * present, the default implementation will return a simple logger
1288 * instance that will route log messages of {@code INFO} level and above to
1289 * the console ({@code System.err}).
1290 * <p>
1291 * <b>Logging Configuration</b>
1292 * <p>
1293 * {@linkplain Logger Logger} instances obtained from the
1294 * {@code LoggerFinder} factory methods are not directly configurable by
1295 * the application. Configuration is the responsibility of the underlying
1296 * logging backend, and usually requires using APIs specific to that backend.
1297 * <p>For the default {@code LoggerFinder} implementation
1298 * using {@code java.util.logging} as its backend, refer to
1299 * {@link java.logging/java.util.logging java.util.logging} for logging configuration.
1300 * For the default {@code LoggerFinder} implementation returning simple loggers
1301 * when the {@code java.logging} module is absent, the configuration
1302 * is implementation dependent.
1303 * <p>
1304 * Usually an application that uses a logging framework will log messages
1305 * through a logger facade defined (or supported) by that framework.
1306 * Applications that wish to use an external framework should log
1307 * through the facade associated with that framework.
1308 * <p>
1309 * A system class that needs to log messages will typically obtain
1310 * a {@link System.Logger} instance to route messages to the logging
1311 * framework selected by the application.
1312 * <p>
1313 * Libraries and classes that only need loggers to produce log messages
1314 * should not attempt to configure loggers by themselves, as that
1315 * would make them dependent from a specific implementation of the
1316 * {@code LoggerFinder} service.
1317 * <p>
1318 * <b>Message Levels and Mapping to backend levels</b>
1319 * <p>
1320 * A logger finder is responsible for mapping from a {@code
1321 * System.Logger.Level} to a level supported by the logging backend it uses.
1322 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1323 * maps {@code System.Logger} levels to
1324 * {@linkplain java.logging/java.util.logging.Level java.util.logging} levels
1325 * of corresponding severity - as described in {@link Logger.Level
1326 * Logger.Level}.
1327 *
1328 * @see java.lang.System
1329 * @see java.lang.System.Logger
1330 *
1331 * @since 9
1332 */
1333 @SuppressWarnings("doclint:reference") // cross-module links
1334 public abstract static class LoggerFinder {
1335
1336 /**
1337 * Creates a new instance of {@code LoggerFinder}.
1338 *
1339 * @implNote It is recommended that a {@code LoggerFinder} service
1340 * implementation does not perform any heavy initialization in its
1341 * constructor, in order to avoid possible risks of deadlock or class
1342 * loading cycles during the instantiation of the service provider.
1343 */
1344 protected LoggerFinder() {
1345 }
1346
1347 /**
1348 * Returns an instance of {@link Logger Logger}
1349 * for the given {@code module}.
1350 *
1351 * @param name the name of the logger.
1352 * @param module the module for which the logger is being requested.
1353 *
1354 * @return a {@link Logger logger} suitable for use within the given
1355 * module.
1356 * @throws NullPointerException if {@code name} is {@code null} or
1357 * {@code module} is {@code null}.
1358 */
1359 public abstract Logger getLogger(String name, Module module);
1360
1361 /**
1362 * Returns a localizable instance of {@link Logger Logger}
1363 * for the given {@code module}.
1364 * The returned logger will use the provided resource bundle for
1365 * message localization.
1366 *
1367 * @implSpec By default, this method calls {@link
1368 * #getLogger(java.lang.String, java.lang.Module)
1369 * this.getLogger(name, module)} to obtain a logger, then wraps that
1370 * logger in a {@link Logger} instance where all methods that do not
1371 * take a {@link ResourceBundle} as parameter are redirected to one
1372 * which does - passing the given {@code bundle} for
1373 * localization. So for instance, a call to {@link
1374 * Logger#log(Logger.Level, String) Logger.log(Level.INFO, msg)}
1375 * will end up as a call to {@link
1376 * Logger#log(Logger.Level, ResourceBundle, String, Object...)
1377 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1378 * logger instance.
1379 * Note however that by default, string messages returned by {@link
1380 * java.util.function.Supplier Supplier<String>} will not be
1381 * localized, as it is assumed that such strings are messages which are
1382 * already constructed, rather than keys in a resource bundle.
1383 * <p>
1384 * An implementation of {@code LoggerFinder} may override this method,
1385 * for example, when the underlying logging backend provides its own
1386 * mechanism for localizing log messages, then such a
1387 * {@code LoggerFinder} would be free to return a logger
1388 * that makes direct use of the mechanism provided by the backend.
1389 *
1390 * @param name the name of the logger.
1391 * @param bundle a resource bundle; can be {@code null}.
1392 * @param module the module for which the logger is being requested.
1393 * @return an instance of {@link Logger Logger} which will use the
1394 * provided resource bundle for message localization.
1395 *
1396 * @throws NullPointerException if {@code name} is {@code null} or
1397 * {@code module} is {@code null}.
1398 */
1399 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1400 Module module) {
1401 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1402 }
1403
1404 /**
1405 * Returns the {@code LoggerFinder} instance. There is one
1406 * single system-wide {@code LoggerFinder} instance in
1407 * the Java Runtime. See the class specification of how the
1408 * {@link LoggerFinder LoggerFinder} implementation is located and
1409 * loaded.
1410 *
1411 * @return the {@link LoggerFinder LoggerFinder} instance.
1412 */
1413 public static LoggerFinder getLoggerFinder() {
1414 return accessProvider();
1415 }
1416
1417
1418 private static volatile LoggerFinder service;
1419 static LoggerFinder accessProvider() {
1420 // We do not need to synchronize: LoggerFinderLoader will
1421 // always return the same instance, so if we don't have it,
1422 // just fetch it again.
1423 LoggerFinder finder = service;
1424 if (finder == null) {
1425 finder = LoggerFinderLoader.getLoggerFinder();
1426 if (finder instanceof TemporaryLoggerFinder) return finder;
1427 service = finder;
1428 }
1429 return finder;
1430 }
1431
1432 }
1433
1434
1435 /**
1436 * Returns an instance of {@link Logger Logger} for the caller's
1437 * use.
1438 *
1439 * @implSpec
1440 * Instances returned by this method route messages to loggers
1441 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1442 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1443 * {@code module} is the caller's module.
1444 * In cases where {@code System.getLogger} is called from a context where
1445 * there is no caller frame on the stack (e.g when called directly
1446 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1447 * To obtain a logger in such a context, use an auxiliary class that will
1448 * implicitly be identified as the caller, or use the system {@link
1449 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1450 * Note that doing the latter may eagerly initialize the underlying
1451 * logging system.
1452 *
1453 * @apiNote
1454 * This method may defer calling the {@link
1455 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1456 * LoggerFinder.getLogger} method to create an actual logger supplied by
1457 * the logging backend, for instance, to allow loggers to be obtained during
1458 * the system initialization time.
1459 *
1460 * @param name the name of the logger.
1461 * @return an instance of {@link Logger} that can be used by the calling
1462 * class.
1463 * @throws NullPointerException if {@code name} is {@code null}.
1464 * @throws IllegalCallerException if there is no Java caller frame on the
1465 * stack.
1466 *
1467 * @since 9
1468 */
1469 @CallerSensitive
1470 public static Logger getLogger(String name) {
1471 Objects.requireNonNull(name);
1472 final Class<?> caller = Reflection.getCallerClass();
1473 if (caller == null) {
1474 throw new IllegalCallerException("no caller frame");
1475 }
1476 return LazyLoggers.getLogger(name, caller.getModule());
1477 }
1478
1479 /**
1480 * Returns a localizable instance of {@link Logger
1481 * Logger} for the caller's use.
1482 * The returned logger will use the provided resource bundle for message
1483 * localization.
1484 *
1485 * @implSpec
1486 * The returned logger will perform message localization as specified
1487 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1488 * java.util.ResourceBundle, java.lang.Module)
1489 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1490 * {@code module} is the caller's module.
1491 * In cases where {@code System.getLogger} is called from a context where
1492 * there is no caller frame on the stack (e.g when called directly
1493 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1494 * To obtain a logger in such a context, use an auxiliary class that
1495 * will implicitly be identified as the caller, or use the system {@link
1496 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1497 * Note that doing the latter may eagerly initialize the underlying
1498 * logging system.
1499 *
1500 * @apiNote
1501 * This method is intended to be used after the system is fully initialized.
1502 * This method may trigger the immediate loading and initialization
1503 * of the {@link LoggerFinder} service, which may cause issues if the
1504 * Java Runtime is not ready to initialize the concrete service
1505 * implementation yet.
1506 * System classes which may be loaded early in the boot sequence and
1507 * need to log localized messages should create a logger using
1508 * {@link #getLogger(java.lang.String)} and then use the log methods that
1509 * take a resource bundle as parameter.
1510 *
1511 * @param name the name of the logger.
1512 * @param bundle a resource bundle.
1513 * @return an instance of {@link Logger} which will use the provided
1514 * resource bundle for message localization.
1515 * @throws NullPointerException if {@code name} is {@code null} or
1516 * {@code bundle} is {@code null}.
1517 * @throws IllegalCallerException if there is no Java caller frame on the
1518 * stack.
1519 *
1520 * @since 9
1521 */
1522 @CallerSensitive
1523 public static Logger getLogger(String name, ResourceBundle bundle) {
1524 final ResourceBundle rb = Objects.requireNonNull(bundle);
1525 Objects.requireNonNull(name);
1526 final Class<?> caller = Reflection.getCallerClass();
1527 if (caller == null) {
1528 throw new IllegalCallerException("no caller frame");
1529 }
1530 return LoggerFinder.accessProvider()
1531 .getLocalizedLogger(name, rb, caller.getModule());
1532 }
1533
1534 /**
1535 * Initiates the {@linkplain Runtime##shutdown shutdown sequence} of the Java Virtual
1536 * Machine. This method initiates the shutdown sequence (if it is not already initiated)
1537 * and then blocks indefinitely. This method neither returns nor throws an exception;
1538 * that is, it does not complete either normally or abruptly.
1539 * <p>
1540 * The argument serves as a status code. By convention, a nonzero status code
1541 * indicates abnormal termination.
1542 * <p>
1543 * The call {@code System.exit(n)} is effectively equivalent to the call:
1544 * {@snippet :
1545 * Runtime.getRuntime().exit(n)
1546 * }
1547 *
1548 * @implNote
1549 * The initiation of the shutdown sequence is logged by {@link Runtime#exit(int)}.
1550 *
1551 * @param status exit status.
1552 * @see java.lang.Runtime#exit(int)
1553 */
1554 public static void exit(int status) {
1555 Runtime.getRuntime().exit(status);
1556 }
1557
1558 /**
1559 * Runs the garbage collector in the Java Virtual Machine.
1560 * <p>
1561 * Calling the {@code gc} method suggests that the Java Virtual Machine
1562 * expend effort toward recycling unused objects in order to
1563 * make the memory they currently occupy available for reuse
1564 * by the Java Virtual Machine.
1565 * When control returns from the method call, the Java Virtual Machine
1566 * has made a best effort to reclaim space from all unused objects.
1567 * There is no guarantee that this effort will recycle any particular
1568 * number of unused objects, reclaim any particular amount of space, or
1569 * complete at any particular time, if at all, before the method returns or ever.
1570 * There is also no guarantee that this effort will determine
1571 * the change of reachability in any particular number of objects,
1572 * or that any particular number of {@link java.lang.ref.Reference Reference}
1573 * objects will be cleared and enqueued.
1574 *
1575 * <p>
1576 * The call {@code System.gc()} is effectively equivalent to the
1577 * call:
1578 * <blockquote><pre>
1579 * Runtime.getRuntime().gc()
1580 * </pre></blockquote>
1581 *
1582 * @see java.lang.Runtime#gc()
1583 */
1584 public static void gc() {
1585 Runtime.getRuntime().gc();
1586 }
1587
1588 /**
1589 * Runs the finalization methods of any objects pending finalization.
1590 *
1591 * Calling this method suggests that the Java Virtual Machine expend
1592 * effort toward running the {@code finalize} methods of objects
1593 * that have been found to be discarded but whose {@code finalize}
1594 * methods have not yet been run. When control returns from the
1595 * method call, the Java Virtual Machine has made a best effort to
1596 * complete all outstanding finalizations.
1597 * <p>
1598 * The call {@code System.runFinalization()} is effectively
1599 * equivalent to the call:
1600 * <blockquote><pre>
1601 * Runtime.getRuntime().runFinalization()
1602 * </pre></blockquote>
1603 *
1604 * @deprecated Finalization has been deprecated for removal. See
1605 * {@link java.lang.Object#finalize} for background information and details
1606 * about migration options.
1607 * <p>
1608 * When running in a JVM in which finalization has been disabled or removed,
1609 * no objects will be pending finalization, so this method does nothing.
1610 *
1611 * @see java.lang.Runtime#runFinalization()
1612 * @jls 12.6 Finalization of Class Instances
1613 */
1614 @Deprecated(since="18", forRemoval=true)
1615 @SuppressWarnings("removal")
1616 public static void runFinalization() {
1617 Runtime.getRuntime().runFinalization();
1618 }
1619
1620 /**
1621 * Loads the native library specified by the filename argument. The filename
1622 * argument must be an absolute path name.
1623 *
1624 * If the filename argument, when stripped of any platform-specific library
1625 * prefix, path, and file extension, indicates a library whose name is,
1626 * for example, L, and a native library called L is statically linked
1627 * with the VM, then the JNI_OnLoad_L function exported by the library
1628 * is invoked rather than attempting to load a dynamic library.
1629 * A filename matching the argument does not have to exist in the
1630 * file system.
1631 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1632 * for more details.
1633 *
1634 * Otherwise, the filename argument is mapped to a native library image in
1635 * an implementation-dependent manner.
1636 *
1637 * <p>
1638 * The call {@code System.load(name)} is effectively equivalent
1639 * to the call:
1640 * <blockquote><pre>
1641 * Runtime.getRuntime().load(name)
1642 * </pre></blockquote>
1643 *
1644 * @param filename the file to load.
1645 * @throws UnsatisfiedLinkError if either the filename is not an
1646 * absolute path name, the native library is not statically
1647 * linked with the VM, or the library cannot be mapped to
1648 * a native library image by the host system.
1649 * @throws NullPointerException if {@code filename} is {@code null}
1650 * @throws IllegalCallerException if the caller is in a module that
1651 * does not have native access enabled.
1652 *
1653 * @spec jni/index.html Java Native Interface Specification
1654 * @see java.lang.Runtime#load(java.lang.String)
1655 */
1656 @CallerSensitive
1657 @Restricted
1658 public static void load(String filename) {
1659 Class<?> caller = Reflection.getCallerClass();
1660 Reflection.ensureNativeAccess(caller, System.class, "load", false);
1661 Runtime.getRuntime().load0(caller, filename);
1662 }
1663
1664 /**
1665 * Loads the native library specified by the {@code libname}
1666 * argument. The {@code libname} argument must not contain any platform
1667 * specific prefix, file extension or path. If a native library
1668 * called {@code libname} is statically linked with the VM, then the
1669 * JNI_OnLoad_{@code libname} function exported by the library is invoked.
1670 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1671 * for more details.
1672 *
1673 * Otherwise, the libname argument is loaded from a system library
1674 * location and mapped to a native library image in an
1675 * implementation-dependent manner.
1676 * <p>
1677 * The call {@code System.loadLibrary(name)} is effectively
1678 * equivalent to the call
1679 * <blockquote><pre>
1680 * Runtime.getRuntime().loadLibrary(name)
1681 * </pre></blockquote>
1682 *
1683 * @param libname the name of the library.
1684 * @throws UnsatisfiedLinkError if either the libname argument
1685 * contains a file path, the native library is not statically
1686 * linked with the VM, or the library cannot be mapped to a
1687 * native library image by the host system.
1688 * @throws NullPointerException if {@code libname} is {@code null}
1689 * @throws IllegalCallerException if the caller is in a module that
1690 * does not have native access enabled.
1691 *
1692 * @spec jni/index.html Java Native Interface Specification
1693 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1694 */
1695 @CallerSensitive
1696 @Restricted
1697 public static void loadLibrary(String libname) {
1698 Class<?> caller = Reflection.getCallerClass();
1699 Reflection.ensureNativeAccess(caller, System.class, "loadLibrary", false);
1700 Runtime.getRuntime().loadLibrary0(caller, libname);
1701 }
1702
1703 /**
1704 * Maps a library name into a platform-specific string representing
1705 * a native library.
1706 *
1707 * @param libname the name of the library.
1708 * @return a platform-dependent native library name.
1709 * @throws NullPointerException if {@code libname} is {@code null}
1710 * @see java.lang.System#loadLibrary(java.lang.String)
1711 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1712 * @since 1.2
1713 */
1714 public static native String mapLibraryName(String libname);
1715
1716 /**
1717 * Create PrintStream for stdout/err based on encoding.
1718 */
1719 private static PrintStream newPrintStream(OutputStream out, String enc) {
1720 if (enc != null) {
1721 return new PrintStream(new BufferedOutputStream(out, 128), true,
1722 Charset.forName(enc, UTF_8.INSTANCE));
1723 }
1724 return new PrintStream(new BufferedOutputStream(out, 128), true);
1725 }
1726
1727 /**
1728 * Logs an exception/error at initialization time to stdout or stderr.
1729 *
1730 * @param printToStderr to print to stderr rather than stdout
1731 * @param printStackTrace to print the stack trace
1732 * @param msg the message to print before the exception, can be {@code null}
1733 * @param e the exception or error
1734 */
1735 private static void logInitException(boolean printToStderr,
1736 boolean printStackTrace,
1737 String msg,
1738 Throwable e) {
1739 if (VM.initLevel() < 1) {
1740 throw new InternalError("system classes not initialized");
1741 }
1742 PrintStream log = (printToStderr) ? err : out;
1743 if (msg != null) {
1744 log.println(msg);
1745 }
1746 if (printStackTrace) {
1747 e.printStackTrace(log);
1748 } else {
1749 log.println(e);
1750 for (Throwable suppressed : e.getSuppressed()) {
1751 log.println("Suppressed: " + suppressed);
1752 }
1753 Throwable cause = e.getCause();
1754 if (cause != null) {
1755 log.println("Caused by: " + cause);
1756 }
1757 }
1758 }
1759
1760 /**
1761 * Create the Properties object from a map - masking out system properties
1762 * that are not intended for public access.
1763 */
1764 private static Properties createProperties(Map<String, String> initialProps) {
1765 Properties properties = new Properties(initialProps.size());
1766 for (var entry : initialProps.entrySet()) {
1767 String prop = entry.getKey();
1768 switch (prop) {
1769 // Do not add private system properties to the Properties
1770 case "sun.nio.MaxDirectMemorySize":
1771 case "sun.nio.PageAlignDirectMemory":
1772 // used by java.lang.Integer.IntegerCache
1773 case "java.lang.Integer.IntegerCache.high":
1774 // used by sun.launcher.LauncherHelper
1775 case "sun.java.launcher.diag":
1776 // used by jdk.internal.loader.ClassLoaders
1777 case "jdk.boot.class.path.append":
1778 break;
1779 default:
1780 properties.put(prop, entry.getValue());
1781 }
1782 }
1783 return properties;
1784 }
1785
1786 /**
1787 * Initialize the system class. Called after thread initialization.
1788 */
1789 private static void initPhase1() {
1790
1791 // register the shared secrets - do this first, since SystemProps.initProperties
1792 // might initialize CharsetDecoders that rely on it
1793 setJavaLangAccess();
1794
1795 // VM might invoke JNU_NewStringPlatform() to set those encoding
1796 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1797 // during "props" initialization.
1798 // The charset is initialized in System.c and does not depend on the Properties.
1799 Map<String, String> tempProps = SystemProps.initProperties();
1800 VersionProps.init(tempProps);
1801
1802 // There are certain system configurations that may be controlled by
1803 // VM options such as the maximum amount of direct memory and
1804 // Integer cache size used to support the object identity semantics
1805 // of autoboxing. Typically, the library will obtain these values
1806 // from the properties set by the VM. If the properties are for
1807 // internal implementation use only, these properties should be
1808 // masked from the system properties.
1809 //
1810 // Save a private copy of the system properties object that
1811 // can only be accessed by the internal implementation.
1812 VM.saveProperties(tempProps);
1813 props = createProperties(tempProps);
1814
1815 // Check if sun.jnu.encoding is supported. If not, replace it with UTF-8.
1816 var jnuEncoding = props.getProperty("sun.jnu.encoding");
1817 if (jnuEncoding == null || !Charset.isSupported(jnuEncoding)) {
1818 notSupportedJnuEncoding = jnuEncoding == null ? "null" : jnuEncoding;
1819 props.setProperty("sun.jnu.encoding", "UTF-8");
1820 }
1821
1822 StaticProperty.javaHome(); // Load StaticProperty to cache the property values
1823
1824 lineSeparator = props.getProperty("line.separator");
1825
1826 FileInputStream fdIn = new In(FileDescriptor.in);
1827 FileOutputStream fdOut = new Out(FileDescriptor.out);
1828 FileOutputStream fdErr = new Out(FileDescriptor.err);
1829 initialIn = new BufferedInputStream(fdIn);
1830 setIn0(initialIn);
1831 // stdout/err.encoding are set when the VM is associated with the terminal,
1832 // thus they are equivalent to Console.charset(), otherwise the encodings
1833 // of those properties default to native.encoding
1834 setOut0(newPrintStream(fdOut, props.getProperty("stdout.encoding")));
1835 initialErr = newPrintStream(fdErr, props.getProperty("stderr.encoding"));
1836 setErr0(initialErr);
1837
1838 // Setup Java signal handlers for HUP, TERM, and INT (where available).
1839 Terminator.setup();
1840
1841 // Initialize any miscellaneous operating system settings that need to be
1842 // set for the class libraries. Currently this is no-op everywhere except
1843 // for Windows where the process-wide error mode is set before the java.io
1844 // classes are used.
1845 VM.initializeOSEnvironment();
1846
1847 // start Finalizer and Reference Handler threads
1848 SharedSecrets.getJavaLangRefAccess().startThreads();
1849
1850 // system properties, java.lang and other core classes are now initialized
1851 VM.initLevel(1);
1852 }
1853
1854 /**
1855 * System.in.
1856 */
1857 private static class In extends FileInputStream {
1858 In(FileDescriptor fd) {
1859 super(fd);
1860 }
1861
1862 @Override
1863 public int read() throws IOException {
1864 boolean attempted = Blocker.begin();
1865 try {
1866 return super.read();
1867 } finally {
1868 Blocker.end(attempted);
1869 }
1870 }
1871
1872 @Override
1873 public int read(byte[] b) throws IOException {
1874 boolean attempted = Blocker.begin();
1875 try {
1876 return super.read(b);
1877 } finally {
1878 Blocker.end(attempted);
1879 }
1880 }
1881
1882 @Override
1883 public int read(byte[] b, int off, int len) throws IOException {
1884 boolean attempted = Blocker.begin();
1885 try {
1886 return super.read(b, off, len);
1887 } finally {
1888 Blocker.end(attempted);
1889 }
1890 }
1891 }
1892
1893 /**
1894 * System.out/System.err wrap this output stream.
1895 */
1896 private static class Out extends FileOutputStream {
1897 Out(FileDescriptor fd) {
1898 super(fd);
1899 }
1900
1901 @Override
1902 public void write(int b) throws IOException {
1903 boolean attempted = Blocker.begin();
1904 try {
1905 super.write(b);
1906 } finally {
1907 Blocker.end(attempted);
1908 }
1909 }
1910
1911 @Override
1912 public void write(byte[] b) throws IOException {
1913 boolean attempted = Blocker.begin();
1914 try {
1915 super.write(b);
1916 } finally {
1917 Blocker.end(attempted);
1918 }
1919 }
1920
1921 @Override
1922 public void write(byte[] b, int off, int len) throws IOException {
1923 boolean attempted = Blocker.begin();
1924 try {
1925 super.write(b, off, len);
1926 } finally {
1927 Blocker.end(attempted);
1928 }
1929 }
1930 }
1931
1932 // @see #initPhase2()
1933 static ModuleLayer bootLayer;
1934
1935 /*
1936 * Invoked by VM. Phase 2 module system initialization.
1937 * Only classes in java.base can be loaded in this phase.
1938 *
1939 * @param printToStderr print exceptions to stderr rather than stdout
1940 * @param printStackTrace print stack trace when exception occurs
1941 *
1942 * @return JNI_OK for success, JNI_ERR for failure
1943 */
1944 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
1945
1946 try {
1947 bootLayer = ModuleBootstrap.boot();
1948 } catch (Exception | Error e) {
1949 logInitException(printToStderr, printStackTrace,
1950 "Error occurred during initialization of boot layer", e);
1951 return -1; // JNI_ERR
1952 }
1953
1954 // module system initialized
1955 VM.initLevel(2);
1956
1957 return 0; // JNI_OK
1958 }
1959
1960 /*
1961 * Invoked by VM. Phase 3 is the final system initialization:
1962 * 1. set system class loader
1963 * 2. set TCCL
1964 *
1965 * This method must be called after the module system initialization.
1966 */
1967 private static void initPhase3() {
1968
1969 // Emit a warning if java.io.tmpdir is set via the command line
1970 // to a directory that doesn't exist
1971 if (SystemProps.isBadIoTmpdir()) {
1972 System.err.println("WARNING: java.io.tmpdir directory does not exist");
1973 }
1974
1975 String smProp = System.getProperty("java.security.manager");
1976 if (smProp != null) {
1977 switch (smProp) {
1978 case "disallow":
1979 break;
1980 case "allow":
1981 case "":
1982 case "default":
1983 default:
1984 throw new Error("A command line option has attempted to allow or enable the Security Manager."
1985 + " Enabling a Security Manager is not supported.");
1986 }
1987 }
1988
1989 // Emit a warning if `sun.jnu.encoding` is not supported.
1990 if (notSupportedJnuEncoding != null) {
1991 System.err.println(
1992 "WARNING: The encoding of the underlying platform's" +
1993 " file system is not supported: " +
1994 notSupportedJnuEncoding);
1995 }
1996
1997 // initializing the system class loader
1998 VM.initLevel(3);
1999
2000 // system class loader initialized
2001 ClassLoader scl = ClassLoader.initSystemClassLoader();
2002
2003 // set TCCL
2004 Thread.currentThread().setContextClassLoader(scl);
2005
2006 // system is fully initialized
2007 VM.initLevel(4);
2008 }
2009
2010 private static void setJavaLangAccess() {
2011 // Allow privileged classes outside of java.lang
2012 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2013 public List<Method> getDeclaredPublicMethods(Class<?> klass, String name, Class<?>... parameterTypes) {
2014 return klass.getDeclaredPublicMethods(name, parameterTypes);
2015 }
2016 public Method findMethod(Class<?> klass, boolean publicOnly, String name, Class<?>... parameterTypes) {
2017 return klass.findMethod(publicOnly, name, parameterTypes);
2018 }
2019 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2020 return klass.getConstantPool();
2021 }
2022 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2023 return klass.casAnnotationType(oldType, newType);
2024 }
2025 public AnnotationType getAnnotationType(Class<?> klass) {
2026 return klass.getAnnotationType();
2027 }
2028 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2029 return klass.getDeclaredAnnotationMap();
2030 }
2031 public byte[] getRawClassAnnotations(Class<?> klass) {
2032 return klass.getRawAnnotations();
2033 }
2034 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2035 return klass.getRawTypeAnnotations();
2036 }
2037 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2038 return Class.getExecutableTypeAnnotationBytes(executable);
2039 }
2040 public int getClassFileAccessFlags(Class<?> klass) {
2041 return klass.getClassFileAccessFlags();
2042 }
2043 public <E extends Enum<E>>
2044 E[] getEnumConstantsShared(Class<E> klass) {
2045 return klass.getEnumConstantsShared();
2046 }
2047 public int classFileVersion(Class<?> clazz) {
2048 return clazz.getClassFileVersion();
2049 }
2050 public void blockedOn(Interruptible b) {
2051 Thread.currentThread().blockedOn(b);
2052 }
2053 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2054 Shutdown.add(slot, registerShutdownInProgress, hook);
2055 }
2056 @SuppressWarnings("removal")
2057 public void invokeFinalize(Object o) throws Throwable {
2058 o.finalize();
2059 }
2060 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2061 return cl.createOrGetClassLoaderValueMap();
2062 }
2063 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2064 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2065 }
2066 public Class<?> defineClass(ClassLoader loader, Class<?> lookup, String name, byte[] b, ProtectionDomain pd,
2067 boolean initialize, int flags, Object classData) {
2068 return ClassLoader.defineClass0(loader, lookup, name, b, 0, b.length, pd, initialize, flags, classData);
2069 }
2070 public Class<?> findBootstrapClassOrNull(String name) {
2071 return ClassLoader.findBootstrapClassOrNull(name);
2072 }
2073 public Package definePackage(ClassLoader cl, String name, Module module) {
2074 return cl.definePackage(name, module);
2075 }
2076 public Module defineModule(ClassLoader loader,
2077 ModuleDescriptor descriptor,
2078 URI uri) {
2079 return new Module(null, loader, descriptor, uri);
2080 }
2081 public Module defineUnnamedModule(ClassLoader loader) {
2082 return new Module(loader);
2083 }
2084 public void addReads(Module m1, Module m2) {
2085 m1.implAddReads(m2);
2086 }
2087 public void addReadsAllUnnamed(Module m) {
2088 m.implAddReadsAllUnnamed();
2089 }
2090 public void addExports(Module m, String pn) {
2091 m.implAddExports(pn);
2092 }
2093 public void addExports(Module m, String pn, Module other) {
2094 m.implAddExports(pn, other);
2095 }
2096 public void addExportsToAllUnnamed(Module m, String pn) {
2097 m.implAddExportsToAllUnnamed(pn);
2098 }
2099 public void addOpens(Module m, String pn, Module other) {
2100 m.implAddOpens(pn, other);
2101 }
2102 public void addOpensToAllUnnamed(Module m, String pn) {
2103 m.implAddOpensToAllUnnamed(pn);
2104 }
2105 public void addUses(Module m, Class<?> service) {
2106 m.implAddUses(service);
2107 }
2108 public boolean isReflectivelyExported(Module m, String pn, Module other) {
2109 return m.isReflectivelyExported(pn, other);
2110 }
2111 public boolean isReflectivelyOpened(Module m, String pn, Module other) {
2112 return m.isReflectivelyOpened(pn, other);
2113 }
2114 public Module addEnableNativeAccess(Module m) {
2115 return m.implAddEnableNativeAccess();
2116 }
2117 public boolean addEnableNativeAccess(ModuleLayer layer, String name) {
2118 return layer.addEnableNativeAccess(name);
2119 }
2120 public void addEnableNativeAccessToAllUnnamed() {
2121 Module.implAddEnableNativeAccessToAllUnnamed();
2122 }
2123 public void ensureNativeAccess(Module m, Class<?> owner, String methodName, Class<?> currentClass, boolean jni) {
2124 m.ensureNativeAccess(owner, methodName, currentClass, jni);
2125 }
2126 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2127 return layer.getServicesCatalog();
2128 }
2129 public void bindToLoader(ModuleLayer layer, ClassLoader loader) {
2130 layer.bindToLoader(loader);
2131 }
2132 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2133 return layer.layers();
2134 }
2135 public Stream<ModuleLayer> layers(ClassLoader loader) {
2136 return ModuleLayer.layers(loader);
2137 }
2138
2139 public int countPositives(byte[] bytes, int offset, int length) {
2140 return StringCoding.countPositives(bytes, offset, length);
2141 }
2142 public int countNonZeroAscii(String s) {
2143 return StringCoding.countNonZeroAscii(s);
2144 }
2145
2146 public String uncheckedNewStringWithLatin1Bytes(byte[] bytes) {
2147 return String.newStringWithLatin1Bytes(bytes);
2148 }
2149
2150 public String uncheckedNewStringNoRepl(byte[] bytes, Charset cs) throws CharacterCodingException {
2151 return String.newStringNoRepl(bytes, cs);
2152 }
2153 public char uncheckedGetUTF16Char(byte[] bytes, int index) {
2154 return StringUTF16.getChar(bytes, index);
2155 }
2156 public void uncheckedPutCharUTF16(byte[] bytes, int index, int ch) {
2157 StringUTF16.putChar(bytes, index, ch);
2158 }
2159 public byte[] uncheckedGetBytesNoRepl(String s, Charset cs) throws CharacterCodingException {
2160 return String.getBytesNoRepl(s, cs);
2161 }
2162
2163 public byte[] getBytesUTF8NoRepl(String s) {
2164 return String.getBytesUTF8NoRepl(s);
2165 }
2166
2167 public void inflateBytesToChars(byte[] src, int srcOff, char[] dst, int dstOff, int len) {
2168 StringLatin1.inflate(src, srcOff, dst, dstOff, len);
2169 }
2170
2171 public int decodeASCII(byte[] src, int srcOff, char[] dst, int dstOff, int len) {
2172 return String.decodeASCII(src, srcOff, dst, dstOff, len);
2173 }
2174
2175 public int encodeASCII(char[] sa, int sp, byte[] da, int dp, int len) {
2176 return StringCoding.encodeAsciiArray(sa, sp, da, dp, len);
2177 }
2178
2179 public InputStream initialSystemIn() {
2180 return initialIn;
2181 }
2182
2183 public PrintStream initialSystemErr() {
2184 return initialErr;
2185 }
2186
2187 public void setCause(Throwable t, Throwable cause) {
2188 t.setCause(cause);
2189 }
2190
2191 public ProtectionDomain protectionDomain(Class<?> c) {
2192 return c.getProtectionDomain();
2193 }
2194
2195 public MethodHandle stringConcatHelper(String name, MethodType methodType) {
2196 return StringConcatHelper.lookupStatic(name, methodType);
2197 }
2198
2199 public long stringConcatInitialCoder() {
2200 return StringConcatHelper.initialCoder();
2201 }
2202
2203 public long stringConcatMix(long lengthCoder, String constant) {
2204 return StringConcatHelper.mix(lengthCoder, constant);
2205 }
2206
2207 public long stringConcatMix(long lengthCoder, char value) {
2208 return StringConcatHelper.mix(lengthCoder, value);
2209 }
2210
2211 public Object uncheckedStringConcat1(String[] constants) {
2212 return new StringConcatHelper.Concat1(constants);
2213 }
2214
2215 public byte stringInitCoder() {
2216 return String.COMPACT_STRINGS ? String.LATIN1 : String.UTF16;
2217 }
2218
2219 public byte stringCoder(String str) {
2220 return str.coder();
2221 }
2222
2223 public String join(String prefix, String suffix, String delimiter, String[] elements, int size) {
2224 return String.join(prefix, suffix, delimiter, elements, size);
2225 }
2226
2227 public String concat(String prefix, Object value, String suffix) {
2228 return StringConcatHelper.concat(prefix, value, suffix);
2229 }
2230
2231 public Object classData(Class<?> c) {
2232 return c.getClassData();
2233 }
2234
2235 @Override
2236 public NativeLibraries nativeLibrariesFor(ClassLoader loader) {
2237 return ClassLoader.nativeLibrariesFor(loader);
2238 }
2239
2240 public Thread[] getAllThreads() {
2241 return Thread.getAllThreads();
2242 }
2243
2244 public ThreadContainer threadContainer(Thread thread) {
2245 return thread.threadContainer();
2246 }
2247
2248 public void start(Thread thread, ThreadContainer container) {
2249 thread.start(container);
2250 }
2251
2252 public StackableScope headStackableScope(Thread thread) {
2253 return thread.headStackableScopes();
2254 }
2255
2256 public void setHeadStackableScope(StackableScope scope) {
2257 Thread.setHeadStackableScope(scope);
2258 }
2259
2260 public Thread currentCarrierThread() {
2261 return Thread.currentCarrierThread();
2262 }
2263
2264 public <T> T getCarrierThreadLocal(CarrierThreadLocal<T> local) {
2265 return ((ThreadLocal<T>)local).getCarrierThreadLocal();
2266 }
2267
2268 public <T> void setCarrierThreadLocal(CarrierThreadLocal<T> local, T value) {
2269 ((ThreadLocal<T>)local).setCarrierThreadLocal(value);
2270 }
2271
2272 public void removeCarrierThreadLocal(CarrierThreadLocal<?> local) {
2273 ((ThreadLocal<?>)local).removeCarrierThreadLocal();
2274 }
2275
2276 public Object[] scopedValueCache() {
2277 return Thread.scopedValueCache();
2278 }
2279
2280 public void setScopedValueCache(Object[] cache) {
2281 Thread.setScopedValueCache(cache);
2282 }
2283
2284 public Object scopedValueBindings() {
2285 return Thread.scopedValueBindings();
2286 }
2287
2288 public Continuation getContinuation(Thread thread) {
2289 return thread.getContinuation();
2290 }
2291
2292 public void setContinuation(Thread thread, Continuation continuation) {
2293 thread.setContinuation(continuation);
2294 }
2295
2296 public ContinuationScope virtualThreadContinuationScope() {
2297 return VirtualThread.continuationScope();
2298 }
2299
2300 public void parkVirtualThread() {
2301 Thread thread = Thread.currentThread();
2302 if (thread instanceof BaseVirtualThread vthread) {
2303 vthread.park();
2304 } else {
2305 throw new WrongThreadException();
2306 }
2307 }
2308
2309 public void parkVirtualThread(long nanos) {
2310 Thread thread = Thread.currentThread();
2311 if (thread instanceof BaseVirtualThread vthread) {
2312 vthread.parkNanos(nanos);
2313 } else {
2314 throw new WrongThreadException();
2315 }
2316 }
2317
2318 public void unparkVirtualThread(Thread thread) {
2319 if (thread instanceof BaseVirtualThread vthread) {
2320 vthread.unpark();
2321 } else {
2322 throw new WrongThreadException();
2323 }
2324 }
2325
2326 public Executor virtualThreadDefaultScheduler() {
2327 return VirtualThread.defaultScheduler();
2328 }
2329
2330 public StackWalker newStackWalkerInstance(Set<StackWalker.Option> options,
2331 ContinuationScope contScope,
2332 Continuation continuation) {
2333 return StackWalker.newInstance(options, null, contScope, continuation);
2334 }
2335
2336 public int classFileFormatVersion(Class<?> clazz) {
2337 return clazz.getClassFileVersion();
2338 }
2339
2340 public String getLoaderNameID(ClassLoader loader) {
2341 return loader != null ? loader.nameAndId() : "null";
2342 }
2343
2344 @Override
2345 public void copyToSegmentRaw(String string, MemorySegment segment, long offset) {
2346 string.copyToSegmentRaw(segment, offset);
2347 }
2348
2349 @Override
2350 public boolean bytesCompatible(String string, Charset charset) {
2351 return string.bytesCompatible(charset);
2352 }
2353 });
2354 }
2355 }