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