1 /*
2 * Copyright (c) 1994, 2018, 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.function.Supplier;
60 import java.util.concurrent.ConcurrentHashMap;
61 import java.util.stream.Stream;
62
63 import jdk.internal.util.StaticProperty;
64 import jdk.internal.module.ModuleBootstrap;
65 import jdk.internal.module.ServicesCatalog;
66 import jdk.internal.reflect.CallerSensitive;
67 import jdk.internal.reflect.Reflection;
68 import jdk.internal.HotSpotIntrinsicCandidate;
69 import jdk.internal.misc.JavaLangAccess;
70 import jdk.internal.misc.SharedSecrets;
71 import jdk.internal.misc.VM;
72 import jdk.internal.logger.LoggerFinderLoader;
73 import jdk.internal.logger.LazyLoggers;
74 import jdk.internal.logger.LocalizedLoggerWrapper;
75 import jdk.internal.vm.annotation.Stable;
76 import sun.reflect.annotation.AnnotationType;
77 import sun.nio.ch.Interruptible;
78 import sun.security.util.SecurityConstants;
79
80 /**
81 * The {@code System} class contains several useful class fields
82 * and methods. It cannot be instantiated.
83 *
84 * Among the facilities provided by the {@code System} class
85 * are standard input, standard output, and error output streams;
86 * access to externally defined properties and environment
87 * variables; a means of loading files and libraries; and a utility
88 * method for quickly copying a portion of an array.
89 *
90 * @since 1.0
91 */
92 public final class System {
93 /* Register the natives via the static initializer.
94 *
95 * VM will invoke the initializeSystemClass method to complete
96 * the initialization for this class separated from clinit.
97 * Note that to use properties set by the VM, see the constraints
98 * described in the initializeSystemClass method.
99 */
100 private static native void registerNatives();
101 static {
102 registerNatives();
103 }
104
105 /** Don't let anyone instantiate this class */
106 private System() {
107 }
108
109 /**
110 * The "standard" input stream. This stream is already
111 * open and ready to supply input data. Typically this stream
112 * corresponds to keyboard input or another input source specified by
113 * the host environment or user.
114 */
115 public static final InputStream in = null;
116
117 /**
118 * The "standard" output stream. This stream is already
119 * open and ready to accept output data. Typically this stream
120 * corresponds to display output or another output destination
121 * specified by the host environment or user.
122 * <p>
123 * For simple stand-alone Java applications, a typical way to write
124 * a line of output data is:
125 * <blockquote><pre>
126 * System.out.println(data)
127 * </pre></blockquote>
128 * <p>
129 * See the {@code println} methods in class {@code PrintStream}.
130 *
131 * @see java.io.PrintStream#println()
132 * @see java.io.PrintStream#println(boolean)
133 * @see java.io.PrintStream#println(char)
134 * @see java.io.PrintStream#println(char[])
135 * @see java.io.PrintStream#println(double)
136 * @see java.io.PrintStream#println(float)
137 * @see java.io.PrintStream#println(int)
138 * @see java.io.PrintStream#println(long)
139 * @see java.io.PrintStream#println(java.lang.Object)
140 * @see java.io.PrintStream#println(java.lang.String)
141 */
142 public static final PrintStream out = null;
143
144 /**
145 * The "standard" error output stream. This stream is already
146 * open and ready to accept output data.
147 * <p>
148 * Typically this stream corresponds to display output or another
149 * output destination specified by the host environment or user. By
150 * convention, this output stream is used to display error messages
151 * or other information that should come to the immediate attention
152 * of a user even if the principal output stream, the value of the
153 * variable {@code out}, has been redirected to a file or other
154 * destination that is typically not continuously monitored.
155 */
156 public static final PrintStream err = null;
157
158 // indicates if a security manager is possible
159 private static final int NEVER = 1;
160 private static final int MAYBE = 2;
161 private static @Stable int allowSecurityManager;
162
163 // current security manager
164 private static volatile SecurityManager security; // read by VM
165
166 // return true if a security manager is allowed
167 private static boolean allowSecurityManager() {
168 return (allowSecurityManager != NEVER);
169 }
170
171 /**
172 * Reassigns the "standard" input stream.
173 *
174 * First, if there is a security manager, its {@code checkPermission}
175 * method is called with a {@code RuntimePermission("setIO")} permission
176 * to see if it's ok to reassign the "standard" input stream.
177 *
178 * @param in the new standard input stream.
179 *
180 * @throws SecurityException
181 * if a security manager exists and its
182 * {@code checkPermission} method doesn't allow
183 * reassigning of the standard input stream.
184 *
185 * @see SecurityManager#checkPermission
186 * @see java.lang.RuntimePermission
187 *
188 * @since 1.1
189 */
190 public static void setIn(InputStream in) {
191 checkIO();
192 setIn0(in);
193 }
194
195 /**
196 * Reassigns the "standard" output stream.
197 *
198 * First, if there is a security manager, its {@code checkPermission}
199 * method is called with a {@code RuntimePermission("setIO")} permission
200 * to see if it's ok to reassign the "standard" output stream.
201 *
202 * @param out the new standard output stream
203 *
204 * @throws SecurityException
205 * if a security manager exists and its
206 * {@code checkPermission} method doesn't allow
207 * reassigning of the standard output stream.
208 *
209 * @see SecurityManager#checkPermission
210 * @see java.lang.RuntimePermission
211 *
212 * @since 1.1
213 */
214 public static void setOut(PrintStream out) {
215 checkIO();
216 setOut0(out);
217 }
218
219 /**
220 * Reassigns the "standard" error output stream.
221 *
222 * First, if there is a security manager, its {@code checkPermission}
223 * method is called with a {@code RuntimePermission("setIO")} permission
224 * to see if it's ok to reassign the "standard" error output stream.
225 *
226 * @param err the new standard error output stream.
227 *
228 * @throws SecurityException
229 * if a security manager exists and its
230 * {@code checkPermission} method doesn't allow
231 * reassigning of the standard error output stream.
232 *
233 * @see SecurityManager#checkPermission
234 * @see java.lang.RuntimePermission
235 *
236 * @since 1.1
237 */
238 public static void setErr(PrintStream err) {
239 checkIO();
240 setErr0(err);
241 }
242
243 private static volatile Console cons;
244
245 /**
246 * Returns the unique {@link java.io.Console Console} object associated
247 * with the current Java virtual machine, if any.
248 *
249 * @return The system console, if any, otherwise {@code null}.
250 *
251 * @since 1.6
252 */
253 public static Console console() {
254 Console c;
255 if ((c = cons) == null) {
256 synchronized (System.class) {
257 if ((c = cons) == null) {
258 cons = c = SharedSecrets.getJavaIOAccess().console();
259 }
260 }
261 }
262 return c;
263 }
264
265 /**
266 * Returns the channel inherited from the entity that created this
267 * Java virtual machine.
268 *
269 * This method returns the channel obtained by invoking the
270 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
271 * inheritedChannel} method of the system-wide default
272 * {@link java.nio.channels.spi.SelectorProvider} object.
273 *
274 * <p> In addition to the network-oriented channels described in
275 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
276 * inheritedChannel}, this method may return other kinds of
277 * channels in the future.
278 *
279 * @return The inherited channel, if any, otherwise {@code null}.
280 *
281 * @throws IOException
282 * If an I/O error occurs
283 *
284 * @throws SecurityException
285 * If a security manager is present and it does not
286 * permit access to the channel.
287 *
288 * @since 1.5
289 */
290 public static Channel inheritedChannel() throws IOException {
291 return SelectorProvider.provider().inheritedChannel();
292 }
293
294 private static void checkIO() {
295 SecurityManager sm = getSecurityManager();
296 if (sm != null) {
297 sm.checkPermission(new RuntimePermission("setIO"));
298 }
299 }
300
301 private static native void setIn0(InputStream in);
302 private static native void setOut0(PrintStream out);
303 private static native void setErr0(PrintStream err);
304
305 /**
306 * Sets the system-wide security manager.
307 *
308 * If there is a security manager already installed, this method first
309 * calls the security manager's {@code checkPermission} method
310 * with a {@code RuntimePermission("setSecurityManager")}
311 * permission to ensure it's ok to replace the existing
312 * security manager.
313 * This may result in throwing a {@code SecurityException}.
314 *
315 * <p> Otherwise, the argument is established as the current
316 * security manager. If the argument is {@code null} and no
317 * security manager has been established, then no action is taken and
318 * the method simply returns.
319 *
320 * @implNote In the JDK implementation, if the Java virtual machine is
321 * started with the system property {@code java.security.manager} set to
322 * the special token "{@code disallow}" then the {@code setSecurityManager}
323 * method cannot be used to set a security manager.
324 *
325 * @param sm the security manager or {@code null}
326 * @throws SecurityException
327 * if the security manager has already been set and its {@code
328 * checkPermission} method doesn't allow it to be replaced
329 * @throws UnsupportedOperationException
330 * if {@code sm} is non-null and a security manager is not allowed
331 * to be set dynamically
332 * @see #getSecurityManager
333 * @see SecurityManager#checkPermission
334 * @see java.lang.RuntimePermission
335 */
336 public static void setSecurityManager(SecurityManager sm) {
337 if (allowSecurityManager()) {
338 if (security == null) {
339 // ensure image reader is initialized
340 Object.class.getResource("java/lang/ANY");
341 }
342 if (sm != null) {
343 try {
344 // pre-populates the SecurityManager.packageAccess cache
345 // to avoid recursive permission checking issues with custom
346 // SecurityManager implementations
347 sm.checkPackageAccess("java.lang");
348 } catch (Exception e) {
349 // no-op
350 }
351 }
352 setSecurityManager0(sm);
353 } else {
354 // security manager not allowed
355 if (sm != null) {
356 throw new UnsupportedOperationException(
357 "Runtime configured to disallow security manager");
358 }
359 }
360 }
361
362 private static synchronized
363 void setSecurityManager0(final SecurityManager s) {
364 SecurityManager sm = getSecurityManager();
365 if (sm != null) {
366 // ask the currently installed security manager if we
367 // can replace it.
368 sm.checkPermission(new RuntimePermission("setSecurityManager"));
369 }
370
371 if ((s != null) && (s.getClass().getClassLoader() != null)) {
372 // New security manager class is not on bootstrap classpath.
373 // Force policy to get initialized before we install the new
374 // security manager, in order to prevent infinite loops when
375 // trying to initialize the policy (which usually involves
376 // accessing some security and/or system properties, which in turn
377 // calls the installed security manager's checkPermission method
378 // which will loop infinitely if there is a non-system class
379 // (in this case: the new security manager class) on the stack).
380 AccessController.doPrivileged(new PrivilegedAction<>() {
381 public Object run() {
382 s.getClass().getProtectionDomain().implies
383 (SecurityConstants.ALL_PERMISSION);
384 return null;
385 }
386 });
387 }
388
389 security = s;
390 }
391
392 /**
393 * Gets the system-wide security manager.
394 *
395 * @return if a security manager has already been established for the
396 * current application, then that security manager is returned;
397 * otherwise, {@code null} is returned.
398 * @see #setSecurityManager
399 */
400 public static SecurityManager getSecurityManager() {
401 if (allowSecurityManager()) {
402 return security;
403 } else {
404 return null;
405 }
406 }
407
408 /**
409 * Returns the current time in milliseconds. Note that
410 * while the unit of time of the return value is a millisecond,
411 * the granularity of the value depends on the underlying
412 * operating system and may be larger. For example, many
413 * operating systems measure time in units of tens of
414 * milliseconds.
415 *
416 * <p> See the description of the class {@code Date} for
417 * a discussion of slight discrepancies that may arise between
418 * "computer time" and coordinated universal time (UTC).
419 *
420 * @return the difference, measured in milliseconds, between
421 * the current time and midnight, January 1, 1970 UTC.
422 * @see java.util.Date
423 */
424 @HotSpotIntrinsicCandidate
425 public static native long currentTimeMillis();
426
427 /**
428 * Returns the current value of the running Java Virtual Machine's
429 * high-resolution time source, in nanoseconds.
430 *
431 * This method can only be used to measure elapsed time and is
432 * not related to any other notion of system or wall-clock time.
433 * The value returned represents nanoseconds since some fixed but
434 * arbitrary <i>origin</i> time (perhaps in the future, so values
435 * may be negative). The same origin is used by all invocations of
436 * this method in an instance of a Java virtual machine; other
437 * virtual machine instances are likely to use a different origin.
438 *
439 * <p>This method provides nanosecond precision, but not necessarily
440 * nanosecond resolution (that is, how frequently the value changes)
441 * - no guarantees are made except that the resolution is at least as
442 * good as that of {@link #currentTimeMillis()}.
443 *
444 * <p>Differences in successive calls that span greater than
445 * approximately 292 years (2<sup>63</sup> nanoseconds) will not
446 * correctly compute elapsed time due to numerical overflow.
447 *
448 * <p>The values returned by this method become meaningful only when
449 * the difference between two such values, obtained within the same
450 * instance of a Java virtual machine, is computed.
451 *
452 * <p>For example, to measure how long some code takes to execute:
453 * <pre> {@code
454 * long startTime = System.nanoTime();
455 * // ... the code being measured ...
456 * long elapsedNanos = System.nanoTime() - startTime;}</pre>
457 *
458 * <p>To compare elapsed time against a timeout, use <pre> {@code
459 * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
460 * instead of <pre> {@code
461 * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
462 * because of the possibility of numerical overflow.
463 *
464 * @return the current value of the running Java Virtual Machine's
465 * high-resolution time source, in nanoseconds
466 * @since 1.5
467 */
468 @HotSpotIntrinsicCandidate
469 public static native long nanoTime();
470
471 /**
472 * Copies an array from the specified source array, beginning at the
473 * specified position, to the specified position of the destination array.
474 * A subsequence of array components are copied from the source
475 * array referenced by {@code src} to the destination array
476 * referenced by {@code dest}. The number of components copied is
477 * equal to the {@code length} argument. The components at
478 * positions {@code srcPos} through
479 * {@code srcPos+length-1} in the source array are copied into
480 * positions {@code destPos} through
481 * {@code destPos+length-1}, respectively, of the destination
482 * array.
483 * <p>
484 * If the {@code src} and {@code dest} arguments refer to the
485 * same array object, then the copying is performed as if the
486 * components at positions {@code srcPos} through
487 * {@code srcPos+length-1} were first copied to a temporary
488 * array with {@code length} components and then the contents of
489 * the temporary array were copied into positions
490 * {@code destPos} through {@code destPos+length-1} of the
491 * destination array.
492 * <p>
493 * If {@code dest} is {@code null}, then a
494 * {@code NullPointerException} is thrown.
495 * <p>
496 * If {@code src} is {@code null}, then a
497 * {@code NullPointerException} is thrown and the destination
498 * array is not modified.
499 * <p>
500 * Otherwise, if any of the following is true, an
501 * {@code ArrayStoreException} is thrown and the destination is
502 * not modified:
503 * <ul>
504 * <li>The {@code src} argument refers to an object that is not an
505 * array.
506 * <li>The {@code dest} argument refers to an object that is not an
507 * array.
508 * <li>The {@code src} argument and {@code dest} argument refer
509 * to arrays whose component types are different primitive types.
510 * <li>The {@code src} argument refers to an array with a primitive
511 * component type and the {@code dest} argument refers to an array
512 * with a reference component type.
513 * <li>The {@code src} argument refers to an array with a reference
514 * component type and the {@code dest} argument refers to an array
515 * with a primitive component type.
516 * </ul>
517 * <p>
518 * Otherwise, if any of the following is true, an
519 * {@code IndexOutOfBoundsException} is
520 * thrown and the destination is not modified:
521 * <ul>
522 * <li>The {@code srcPos} argument is negative.
523 * <li>The {@code destPos} argument is negative.
524 * <li>The {@code length} argument is negative.
525 * <li>{@code srcPos+length} is greater than
526 * {@code src.length}, the length of the source array.
527 * <li>{@code destPos+length} is greater than
528 * {@code dest.length}, the length of the destination array.
529 * </ul>
530 * <p>
531 * Otherwise, if any actual component of the source array from
532 * position {@code srcPos} through
533 * {@code srcPos+length-1} cannot be converted to the component
534 * type of the destination array by assignment conversion, an
535 * {@code ArrayStoreException} is thrown. In this case, let
536 * <b><i>k</i></b> be the smallest nonnegative integer less than
537 * length such that {@code src[srcPos+}<i>k</i>{@code ]}
538 * cannot be converted to the component type of the destination
539 * array; when the exception is thrown, source array components from
540 * positions {@code srcPos} through
541 * {@code srcPos+}<i>k</i>{@code -1}
542 * will already have been copied to destination array positions
543 * {@code destPos} through
544 * {@code destPos+}<i>k</I>{@code -1} and no other
545 * positions of the destination array will have been modified.
546 * (Because of the restrictions already itemized, this
547 * paragraph effectively applies only to the situation where both
548 * arrays have component types that are reference types.)
549 *
550 * @param src the source array.
551 * @param srcPos starting position in the source array.
552 * @param dest the destination array.
553 * @param destPos starting position in the destination data.
554 * @param length the number of array elements to be copied.
555 * @throws IndexOutOfBoundsException if copying would cause
556 * access of data outside array bounds.
557 * @throws ArrayStoreException if an element in the {@code src}
558 * array could not be stored into the {@code dest} array
559 * because of a type mismatch.
560 * @throws NullPointerException if either {@code src} or
561 * {@code dest} is {@code null}.
562 */
563 @HotSpotIntrinsicCandidate
564 public static native void arraycopy(Object src, int srcPos,
565 Object dest, int destPos,
566 int length);
567
568 /**
569 * Returns the same hash code for the given object as
570 * would be returned by the default method hashCode(),
571 * whether or not the given object's class overrides
572 * hashCode().
573 * The hash code for the null reference is zero.
574 *
575 * @param x object for which the hashCode is to be calculated
576 * @return the hashCode
577 * @since 1.1
578 * @see Object#hashCode
579 * @see java.util.Objects#hashCode(Object)
580 */
581 @HotSpotIntrinsicCandidate
582 public static native int identityHashCode(Object x);
583
584 /**
585 * System properties. The following properties are guaranteed to be defined:
586 * <dl>
587 * <dt>java.version <dd>Java version number
588 * <dt>java.version.date <dd>Java version date
589 * <dt>java.vendor <dd>Java vendor specific string
590 * <dt>java.vendor.url <dd>Java vendor URL
591 * <dt>java.vendor.version <dd>Java vendor version
592 * <dt>java.home <dd>Java installation directory
593 * <dt>java.class.version <dd>Java class version number
594 * <dt>java.class.path <dd>Java classpath
595 * <dt>os.name <dd>Operating System Name
596 * <dt>os.arch <dd>Operating System Architecture
597 * <dt>os.version <dd>Operating System Version
598 * <dt>file.separator <dd>File separator ("/" on Unix)
599 * <dt>path.separator <dd>Path separator (":" on Unix)
600 * <dt>line.separator <dd>Line separator ("\n" on Unix)
601 * <dt>user.name <dd>User account name
602 * <dt>user.home <dd>User home directory
603 * <dt>user.dir <dd>User's current working directory
604 * </dl>
605 */
606
607 private static Properties props;
608 private static native Properties initProperties(Properties props);
609
610 /**
611 * Determines the current system properties.
612 *
613 * First, if there is a security manager, its
614 * {@code checkPropertiesAccess} method is called with no
615 * arguments. This may result in a security exception.
616 * <p>
617 * The current set of system properties for use by the
618 * {@link #getProperty(String)} method is returned as a
619 * {@code Properties} object. If there is no current set of
620 * system properties, a set of system properties is first created and
621 * initialized. This set of system properties always includes values
622 * for the following keys:
623 * <table class="striped" style="text-align:left">
624 * <caption style="display:none">Shows property keys and associated values</caption>
625 * <thead>
626 * <tr><th scope="col">Key</th>
627 * <th scope="col">Description of Associated Value</th></tr>
628 * </thead>
629 * <tbody>
630 * <tr><th scope="row">{@code java.version}</th>
631 * <td>Java Runtime Environment version, which may be interpreted
632 * as a {@link Runtime.Version}</td></tr>
633 * <tr><th scope="row">{@code java.version.date}</th>
634 * <td>Java Runtime Environment version date, in ISO-8601 YYYY-MM-DD
635 * format, which may be interpreted as a {@link
636 * java.time.LocalDate}</td></tr>
637 * <tr><th scope="row">{@code java.vendor}</th>
638 * <td>Java Runtime Environment vendor</td></tr>
639 * <tr><th scope="row">{@code java.vendor.url}</th>
640 * <td>Java vendor URL</td></tr>
641 * <tr><th scope="row">{@code java.vendor.version}</th>
642 * <td>Java vendor version</td></tr>
643 * <tr><th scope="row">{@code java.home}</th>
644 * <td>Java installation directory</td></tr>
645 * <tr><th scope="row">{@code java.vm.specification.version}</th>
646 * <td>Java Virtual Machine specification version, whose value is the
647 * {@linkplain Runtime.Version#feature feature} element of the
648 * {@linkplain Runtime#version() runtime version}</td></tr>
649 * <tr><th scope="row">{@code java.vm.specification.vendor}</th>
650 * <td>Java Virtual Machine specification vendor</td></tr>
651 * <tr><th scope="row">{@code java.vm.specification.name}</th>
652 * <td>Java Virtual Machine specification name</td></tr>
653 * <tr><th scope="row">{@code java.vm.version}</th>
654 * <td>Java Virtual Machine implementation version which may be
655 * interpreted as a {@link Runtime.Version}</td></tr>
656 * <tr><th scope="row">{@code java.vm.vendor}</th>
657 * <td>Java Virtual Machine implementation vendor</td></tr>
658 * <tr><th scope="row">{@code java.vm.name}</th>
659 * <td>Java Virtual Machine implementation name</td></tr>
660 * <tr><th scope="row">{@code java.specification.version}</th>
661 * <td>Java Runtime Environment specification version, whose value is
662 * the {@linkplain Runtime.Version#feature feature} element of the
663 * {@linkplain Runtime#version() runtime version}</td></tr>
664 * <tr><th scope="row">{@code java.specification.vendor}</th>
665 * <td>Java Runtime Environment specification vendor</td></tr>
666 * <tr><th scope="row">{@code java.specification.name}</th>
667 * <td>Java Runtime Environment specification name</td></tr>
668 * <tr><th scope="row">{@code java.class.version}</th>
669 * <td>Java class format version number</td></tr>
670 * <tr><th scope="row">{@code java.class.path}</th>
671 * <td>Java class path (refer to
672 * {@link ClassLoader#getSystemClassLoader()} for details)</td></tr>
673 * <tr><th scope="row">{@code java.library.path}</th>
674 * <td>List of paths to search when loading libraries</td></tr>
675 * <tr><th scope="row">{@code java.io.tmpdir}</th>
676 * <td>Default temp file path</td></tr>
677 * <tr><th scope="row">{@code java.compiler}</th>
678 * <td>Name of JIT compiler to use</td></tr>
679 * <tr><th scope="row">{@code os.name}</th>
680 * <td>Operating system name</td></tr>
681 * <tr><th scope="row">{@code os.arch}</th>
682 * <td>Operating system architecture</td></tr>
683 * <tr><th scope="row">{@code os.version}</th>
684 * <td>Operating system version</td></tr>
685 * <tr><th scope="row">{@code file.separator}</th>
686 * <td>File separator ("/" on UNIX)</td></tr>
687 * <tr><th scope="row">{@code path.separator}</th>
688 * <td>Path separator (":" on UNIX)</td></tr>
689 * <tr><th scope="row">{@code line.separator}</th>
690 * <td>Line separator ("\n" on UNIX)</td></tr>
691 * <tr><th scope="row">{@code user.name}</th>
692 * <td>User's account name</td></tr>
693 * <tr><th scope="row">{@code user.home}</th>
694 * <td>User's home directory</td></tr>
695 * <tr><th scope="row">{@code user.dir}</th>
696 * <td>User's current working directory</td></tr>
697 * </tbody>
698 * </table>
699 * <p>
700 * Multiple paths in a system property value are separated by the path
701 * separator character of the platform.
702 * <p>
703 * Note that even if the security manager does not permit the
704 * {@code getProperties} operation, it may choose to permit the
705 * {@link #getProperty(String)} operation.
706 *
707 * @apiNote
708 * <strong>Changing a standard system property may have unpredictable results
709 * unless otherwise specified.</strong>
710 * Property values may be cached during initialization or on first use.
711 * Setting a standard property after initialization using {@link #getProperties()},
712 * {@link #setProperties(Properties)}, {@link #setProperty(String, String)}, or
713 * {@link #clearProperty(String)} may not have the desired effect.
714 *
715 * @implNote
716 * In addition to the standard system properties, the system
717 * properties may include the following keys:
718 * <table class="striped">
719 * <caption style="display:none">Shows property keys and associated values</caption>
720 * <thead>
721 * <tr><th scope="col">Key</th>
722 * <th scope="col">Description of Associated Value</th></tr>
723 * </thead>
724 * <tbody>
725 * <tr><th scope="row">{@code jdk.module.path}</th>
726 * <td>The application module path</td></tr>
727 * <tr><th scope="row">{@code jdk.module.upgrade.path}</th>
728 * <td>The upgrade module path</td></tr>
729 * <tr><th scope="row">{@code jdk.module.main}</th>
730 * <td>The module name of the initial/main module</td></tr>
731 * <tr><th scope="row">{@code jdk.module.main.class}</th>
732 * <td>The main class name of the initial module</td></tr>
733 * </tbody>
734 * </table>
735 *
736 * @return the system properties
737 * @throws SecurityException if a security manager exists and its
738 * {@code checkPropertiesAccess} method doesn't allow access
739 * to the system properties.
740 * @see #setProperties
741 * @see java.lang.SecurityException
742 * @see java.lang.SecurityManager#checkPropertiesAccess()
743 * @see java.util.Properties
744 */
745 public static Properties getProperties() {
746 SecurityManager sm = getSecurityManager();
747 if (sm != null) {
748 sm.checkPropertiesAccess();
749 }
750
751 return props;
752 }
753
754 /**
755 * Returns the system-dependent line separator string. It always
756 * returns the same value - the initial value of the {@linkplain
757 * #getProperty(String) system property} {@code line.separator}.
758 *
759 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
760 * Windows systems it returns {@code "\r\n"}.
761 *
762 * @return the system-dependent line separator string
763 * @since 1.7
764 */
765 public static String lineSeparator() {
766 return lineSeparator;
767 }
768
769 private static String lineSeparator;
770
771 /**
772 * Sets the system properties to the {@code Properties} argument.
773 *
774 * First, if there is a security manager, its
775 * {@code checkPropertiesAccess} method is called with no
776 * arguments. This may result in a security exception.
777 * <p>
778 * The argument becomes the current set of system properties for use
779 * by the {@link #getProperty(String)} method. If the argument is
780 * {@code null}, then the current set of system properties is
781 * forgotten.
782 *
783 * @apiNote
784 * <strong>Changing a standard system property may have unpredictable results
785 * unless otherwise specified</strong>.
786 * See {@linkplain #getProperties getProperties} for details.
787 *
788 * @param props the new system properties.
789 * @throws SecurityException if a security manager exists and its
790 * {@code checkPropertiesAccess} method doesn't allow access
791 * to the system properties.
792 * @see #getProperties
793 * @see java.util.Properties
794 * @see java.lang.SecurityException
795 * @see java.lang.SecurityManager#checkPropertiesAccess()
796 */
797 public static void setProperties(Properties props) {
798 SecurityManager sm = getSecurityManager();
799 if (sm != null) {
800 sm.checkPropertiesAccess();
801 }
802 if (props == null) {
803 props = new Properties();
804 initProperties(props);
805 }
806 System.props = props;
807 }
808
809 /**
810 * Gets the system property indicated by the specified key.
811 *
812 * First, if there is a security manager, its
813 * {@code checkPropertyAccess} method is called with the key as
814 * its argument. This may result in a SecurityException.
815 * <p>
816 * If there is no current set of system properties, a set of system
817 * properties is first created and initialized in the same manner as
818 * for the {@code getProperties} method.
819 *
820 * @apiNote
821 * <strong>Changing a standard system property may have unpredictable results
822 * unless otherwise specified</strong>.
823 * See {@linkplain #getProperties getProperties} for details.
824 *
825 * @param key the name of the system property.
826 * @return the string value of the system property,
827 * or {@code null} if there is no property with that key.
828 *
829 * @throws SecurityException if a security manager exists and its
830 * {@code checkPropertyAccess} method doesn't allow
831 * access to the specified system property.
832 * @throws NullPointerException if {@code key} is {@code null}.
833 * @throws IllegalArgumentException if {@code key} is empty.
834 * @see #setProperty
835 * @see java.lang.SecurityException
836 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
837 * @see java.lang.System#getProperties()
838 */
839 public static String getProperty(String key) {
840 checkKey(key);
841 SecurityManager sm = getSecurityManager();
842 if (sm != null) {
843 sm.checkPropertyAccess(key);
844 }
845
846 return props.getProperty(key);
847 }
848
849 /**
850 * Gets the system property indicated by the specified key.
851 *
852 * First, if there is a security manager, its
853 * {@code checkPropertyAccess} method is called with the
854 * {@code key} as its argument.
855 * <p>
856 * If there is no current set of system properties, a set of system
857 * properties is first created and initialized in the same manner as
858 * for the {@code getProperties} method.
859 *
860 * @param key the name of the system property.
861 * @param def a default value.
862 * @return the string value of the system property,
863 * or the default value if there is no property with that key.
864 *
865 * @throws SecurityException if a security manager exists and its
866 * {@code checkPropertyAccess} method doesn't allow
867 * access to the specified system property.
868 * @throws NullPointerException if {@code key} is {@code null}.
869 * @throws IllegalArgumentException if {@code key} is empty.
870 * @see #setProperty
871 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
872 * @see java.lang.System#getProperties()
873 */
874 public static String getProperty(String key, String def) {
875 checkKey(key);
876 SecurityManager sm = getSecurityManager();
877 if (sm != null) {
878 sm.checkPropertyAccess(key);
879 }
880
881 return props.getProperty(key, def);
882 }
883
884 /**
885 * Sets the system property indicated by the specified key.
886 *
887 * First, if a security manager exists, its
888 * {@code SecurityManager.checkPermission} method
889 * is called with a {@code PropertyPermission(key, "write")}
890 * permission. This may result in a SecurityException being thrown.
891 * If no exception is thrown, the specified property is set to the given
892 * value.
893 *
894 * @apiNote
895 * <strong>Changing a standard system property may have unpredictable results
896 * unless otherwise specified</strong>.
897 * See {@linkplain #getProperties getProperties} for details.
898 *
899 * @param key the name of the system property.
900 * @param value the value of the system property.
901 * @return the previous value of the system property,
902 * or {@code null} if it did not have one.
903 *
904 * @throws SecurityException if a security manager exists and its
905 * {@code checkPermission} method doesn't allow
906 * setting of the specified property.
907 * @throws NullPointerException if {@code key} or
908 * {@code value} is {@code null}.
909 * @throws IllegalArgumentException if {@code key} is empty.
910 * @see #getProperty
911 * @see java.lang.System#getProperty(java.lang.String)
912 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
913 * @see java.util.PropertyPermission
914 * @see SecurityManager#checkPermission
915 * @since 1.2
916 */
917 public static String setProperty(String key, String value) {
918 checkKey(key);
919 SecurityManager sm = getSecurityManager();
920 if (sm != null) {
921 sm.checkPermission(new PropertyPermission(key,
922 SecurityConstants.PROPERTY_WRITE_ACTION));
923 }
924
925 return (String) props.setProperty(key, value);
926 }
927
928 /**
929 * Removes the system property indicated by the specified key.
930 *
931 * First, if a security manager exists, its
932 * {@code SecurityManager.checkPermission} method
933 * is called with a {@code PropertyPermission(key, "write")}
934 * permission. This may result in a SecurityException being thrown.
935 * If no exception is thrown, the specified property is removed.
936 *
937 * @apiNote
938 * <strong>Changing a standard system property may have unpredictable results
939 * unless otherwise specified</strong>.
940 * See {@linkplain #getProperties getProperties} method for details.
941 *
942 * @param key the name of the system property to be removed.
943 * @return the previous string value of the system property,
944 * or {@code null} if there was no property with that key.
945 *
946 * @throws SecurityException if a security manager exists and its
947 * {@code checkPropertyAccess} method doesn't allow
948 * access to the specified system property.
949 * @throws NullPointerException if {@code key} is {@code null}.
950 * @throws IllegalArgumentException if {@code key} is empty.
951 * @see #getProperty
952 * @see #setProperty
953 * @see java.util.Properties
954 * @see java.lang.SecurityException
955 * @see java.lang.SecurityManager#checkPropertiesAccess()
956 * @since 1.5
957 */
958 public static String clearProperty(String key) {
959 checkKey(key);
960 SecurityManager sm = getSecurityManager();
961 if (sm != null) {
962 sm.checkPermission(new PropertyPermission(key, "write"));
963 }
964
965 return (String) props.remove(key);
966 }
967
968 private static void checkKey(String key) {
969 if (key == null) {
970 throw new NullPointerException("key can't be null");
971 }
972 if (key.equals("")) {
973 throw new IllegalArgumentException("key can't be empty");
974 }
975 }
976
977 /**
978 * Gets the value of the specified environment variable. An
979 * environment variable is a system-dependent external named
980 * value.
981 *
982 * <p>If a security manager exists, its
983 * {@link SecurityManager#checkPermission checkPermission}
984 * method is called with a
985 * {@code {@link RuntimePermission}("getenv."+name)}
986 * permission. This may result in a {@link SecurityException}
987 * being thrown. If no exception is thrown the value of the
988 * variable {@code name} is returned.
989 *
990 * <p><a id="EnvironmentVSSystemProperties"><i>System
991 * properties</i> and <i>environment variables</i></a> are both
992 * conceptually mappings between names and values. Both
993 * mechanisms can be used to pass user-defined information to a
994 * Java process. Environment variables have a more global effect,
995 * because they are visible to all descendants of the process
996 * which defines them, not just the immediate Java subprocess.
997 * They can have subtly different semantics, such as case
998 * insensitivity, on different operating systems. For these
999 * reasons, environment variables are more likely to have
1000 * unintended side effects. It is best to use system properties
1001 * where possible. Environment variables should be used when a
1002 * global effect is desired, or when an external system interface
1003 * requires an environment variable (such as {@code PATH}).
1004 *
1005 * <p>On UNIX systems the alphabetic case of {@code name} is
1006 * typically significant, while on Microsoft Windows systems it is
1007 * typically not. For example, the expression
1008 * {@code System.getenv("FOO").equals(System.getenv("foo"))}
1009 * is likely to be true on Microsoft Windows.
1010 *
1011 * @param name the name of the environment variable
1012 * @return the string value of the variable, or {@code null}
1013 * if the variable is not defined in the system environment
1014 * @throws NullPointerException if {@code name} is {@code null}
1015 * @throws SecurityException
1016 * if a security manager exists and its
1017 * {@link SecurityManager#checkPermission checkPermission}
1018 * method doesn't allow access to the environment variable
1019 * {@code name}
1020 * @see #getenv()
1021 * @see ProcessBuilder#environment()
1022 */
1023 public static String getenv(String name) {
1024 SecurityManager sm = getSecurityManager();
1025 if (sm != null) {
1026 sm.checkPermission(new RuntimePermission("getenv."+name));
1027 }
1028
1029 return ProcessEnvironment.getenv(name);
1030 }
1031
1032
1033 /**
1034 * Returns an unmodifiable string map view of the current system environment.
1035 * The environment is a system-dependent mapping from names to
1036 * values which is passed from parent to child processes.
1037 *
1038 * <p>If the system does not support environment variables, an
1039 * empty map is returned.
1040 *
1041 * <p>The returned map will never contain null keys or values.
1042 * Attempting to query the presence of a null key or value will
1043 * throw a {@link NullPointerException}. Attempting to query
1044 * the presence of a key or value which is not of type
1045 * {@link String} will throw a {@link ClassCastException}.
1046 *
1047 * <p>The returned map and its collection views may not obey the
1048 * general contract of the {@link Object#equals} and
1049 * {@link Object#hashCode} methods.
1050 *
1051 * <p>The returned map is typically case-sensitive on all platforms.
1052 *
1053 * <p>If a security manager exists, its
1054 * {@link SecurityManager#checkPermission checkPermission}
1055 * method is called with a
1056 * {@code {@link RuntimePermission}("getenv.*")} permission.
1057 * This may result in a {@link SecurityException} being thrown.
1058 *
1059 * <p>When passing information to a Java subprocess,
1060 * <a href=#EnvironmentVSSystemProperties>system properties</a>
1061 * are generally preferred over environment variables.
1062 *
1063 * @return the environment as a map of variable names to values
1064 * @throws SecurityException
1065 * if a security manager exists and its
1066 * {@link SecurityManager#checkPermission checkPermission}
1067 * method doesn't allow access to the process environment
1068 * @see #getenv(String)
1069 * @see ProcessBuilder#environment()
1070 * @since 1.5
1071 */
1072 public static java.util.Map<String,String> getenv() {
1073 SecurityManager sm = getSecurityManager();
1074 if (sm != null) {
1075 sm.checkPermission(new RuntimePermission("getenv.*"));
1076 }
1077
1078 return ProcessEnvironment.getenv();
1079 }
1080
1081 /**
1082 * {@code System.Logger} instances log messages that will be
1083 * routed to the underlying logging framework the {@link System.LoggerFinder
1084 * LoggerFinder} uses.
1085 *
1086 * {@code System.Logger} instances are typically obtained from
1087 * the {@link java.lang.System System} class, by calling
1088 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
1089 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1090 * System.getLogger(loggerName, bundle)}.
1091 *
1092 * @see java.lang.System#getLogger(java.lang.String)
1093 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1094 * @see java.lang.System.LoggerFinder
1095 *
1096 * @since 9
1097 */
1098 public interface Logger {
1099
1100 /**
1101 * System {@linkplain Logger loggers} levels.
1102 *
1103 * A level has a {@linkplain #getName() name} and {@linkplain
1104 * #getSeverity() severity}.
1105 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
1106 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
1107 * by order of increasing severity.
1108 * <br>
1109 * {@link #ALL} and {@link #OFF}
1110 * are simple markers with severities mapped respectively to
1111 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
1112 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
1113 * <p>
1114 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
1115 * <p>
1116 * {@linkplain System.Logger.Level System logger levels} are mapped to
1117 * {@linkplain java.util.logging.Level java.util.logging levels}
1118 * of corresponding severity.
1119 * <br>The mapping is as follows:
1120 * <br><br>
1121 * <table class="striped">
1122 * <caption>System.Logger Severity Level Mapping</caption>
1123 * <thead>
1124 * <tr><th scope="col">System.Logger Levels</th>
1125 * <th scope="col">java.util.logging Levels</th>
1126 * </thead>
1127 * <tbody>
1128 * <tr><th scope="row">{@link Logger.Level#ALL ALL}</th>
1129 * <td>{@link java.util.logging.Level#ALL ALL}</td>
1130 * <tr><th scope="row">{@link Logger.Level#TRACE TRACE}</th>
1131 * <td>{@link java.util.logging.Level#FINER FINER}</td>
1132 * <tr><th scope="row">{@link Logger.Level#DEBUG DEBUG}</th>
1133 * <td>{@link java.util.logging.Level#FINE FINE}</td>
1134 * <tr><th scope="row">{@link Logger.Level#INFO INFO}</th>
1135 * <td>{@link java.util.logging.Level#INFO INFO}</td>
1136 * <tr><th scope="row">{@link Logger.Level#WARNING WARNING}</th>
1137 * <td>{@link java.util.logging.Level#WARNING WARNING}</td>
1138 * <tr><th scope="row">{@link Logger.Level#ERROR ERROR}</th>
1139 * <td>{@link java.util.logging.Level#SEVERE SEVERE}</td>
1140 * <tr><th scope="row">{@link Logger.Level#OFF OFF}</th>
1141 * <td>{@link java.util.logging.Level#OFF OFF}</td>
1142 * </tbody>
1143 * </table>
1144 *
1145 * @since 9
1146 *
1147 * @see java.lang.System.LoggerFinder
1148 * @see java.lang.System.Logger
1149 */
1150 public enum Level {
1151
1152 // for convenience, we're reusing java.util.logging.Level int values
1153 // the mapping logic in sun.util.logging.PlatformLogger depends
1154 // on this.
1155 /**
1156 * A marker to indicate that all levels are enabled.
1157 * This level {@linkplain #getSeverity() severity} is
1158 * {@link Integer#MIN_VALUE}.
1159 */
1160 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
1161 /**
1162 * {@code TRACE} level: usually used to log diagnostic information.
1163 * This level {@linkplain #getSeverity() severity} is
1164 * {@code 400}.
1165 */
1166 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1167 /**
1168 * {@code DEBUG} level: usually used to log debug information traces.
1169 * This level {@linkplain #getSeverity() severity} is
1170 * {@code 500}.
1171 */
1172 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1173 /**
1174 * {@code INFO} level: usually used to log information messages.
1175 * This level {@linkplain #getSeverity() severity} is
1176 * {@code 800}.
1177 */
1178 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1179 /**
1180 * {@code WARNING} level: usually used to log warning messages.
1181 * This level {@linkplain #getSeverity() severity} is
1182 * {@code 900}.
1183 */
1184 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1185 /**
1186 * {@code ERROR} level: usually used to log error messages.
1187 * This level {@linkplain #getSeverity() severity} is
1188 * {@code 1000}.
1189 */
1190 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1191 /**
1192 * A marker to indicate that all levels are disabled.
1193 * This level {@linkplain #getSeverity() severity} is
1194 * {@link Integer#MAX_VALUE}.
1195 */
1196 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1197
1198 private final int severity;
1199
1200 private Level(int severity) {
1201 this.severity = severity;
1202 }
1203
1204 /**
1205 * Returns the name of this level.
1206 * @return this level {@linkplain #name()}.
1207 */
1208 public final String getName() {
1209 return name();
1210 }
1211
1212 /**
1213 * Returns the severity of this level.
1214 * A higher severity means a more severe condition.
1215 * @return this level severity.
1216 */
1217 public final int getSeverity() {
1218 return severity;
1219 }
1220 }
1221
1222 /**
1223 * Returns the name of this logger.
1224 *
1225 * @return the logger name.
1226 */
1227 public String getName();
1228
1229 /**
1230 * Checks if a message of the given level would be logged by
1231 * this logger.
1232 *
1233 * @param level the log message level.
1234 * @return {@code true} if the given log message level is currently
1235 * being logged.
1236 *
1237 * @throws NullPointerException if {@code level} is {@code null}.
1238 */
1239 public boolean isLoggable(Level level);
1240
1241 /**
1242 * Logs a message.
1243 *
1244 * @implSpec The default implementation for this method calls
1245 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1246 *
1247 * @param level the log message level.
1248 * @param msg the string message (or a key in the message catalog, if
1249 * this logger is a {@link
1250 * LoggerFinder#getLocalizedLogger(java.lang.String,
1251 * java.util.ResourceBundle, java.lang.Module) localized logger});
1252 * can be {@code null}.
1253 *
1254 * @throws NullPointerException if {@code level} is {@code null}.
1255 */
1256 public default void log(Level level, String msg) {
1257 log(level, (ResourceBundle) null, msg, (Object[]) null);
1258 }
1259
1260 /**
1261 * Logs a lazily supplied message.
1262 *
1263 * If the logger is currently enabled for the given log message level
1264 * then a message is logged that is the result produced by the
1265 * given supplier function. Otherwise, the supplier is not operated on.
1266 *
1267 * @implSpec When logging is enabled for the given level, the default
1268 * implementation for this method calls
1269 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1270 *
1271 * @param level the log message level.
1272 * @param msgSupplier a supplier function that produces a message.
1273 *
1274 * @throws NullPointerException if {@code level} is {@code null},
1275 * or {@code msgSupplier} is {@code null}.
1276 */
1277 public default void log(Level level, Supplier<String> msgSupplier) {
1278 Objects.requireNonNull(msgSupplier);
1279 if (isLoggable(Objects.requireNonNull(level))) {
1280 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1281 }
1282 }
1283
1284 /**
1285 * Logs a message produced from the given object.
1286 *
1287 * If the logger is currently enabled for the given log message level then
1288 * a message is logged that, by default, is the result produced from
1289 * calling toString on the given object.
1290 * Otherwise, the object is not operated on.
1291 *
1292 * @implSpec When logging is enabled for the given level, the default
1293 * implementation for this method calls
1294 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1295 *
1296 * @param level the log message level.
1297 * @param obj the object to log.
1298 *
1299 * @throws NullPointerException if {@code level} is {@code null}, or
1300 * {@code obj} is {@code null}.
1301 */
1302 public default void log(Level level, Object obj) {
1303 Objects.requireNonNull(obj);
1304 if (isLoggable(Objects.requireNonNull(level))) {
1305 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1306 }
1307 }
1308
1309 /**
1310 * Logs a message associated with a given throwable.
1311 *
1312 * @implSpec The default implementation for this method calls
1313 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1314 *
1315 * @param level the log message level.
1316 * @param msg the string message (or a key in the message catalog, if
1317 * this logger is a {@link
1318 * LoggerFinder#getLocalizedLogger(java.lang.String,
1319 * java.util.ResourceBundle, java.lang.Module) localized logger});
1320 * can be {@code null}.
1321 * @param thrown a {@code Throwable} associated with the log message;
1322 * can be {@code null}.
1323 *
1324 * @throws NullPointerException if {@code level} is {@code null}.
1325 */
1326 public default void log(Level level, String msg, Throwable thrown) {
1327 this.log(level, null, msg, thrown);
1328 }
1329
1330 /**
1331 * Logs a lazily supplied message associated with a given throwable.
1332 *
1333 * If the logger is currently enabled for the given log message level
1334 * then a message is logged that is the result produced by the
1335 * given supplier function. Otherwise, the supplier is not operated on.
1336 *
1337 * @implSpec When logging is enabled for the given level, the default
1338 * implementation for this method calls
1339 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1340 *
1341 * @param level one of the log message level identifiers.
1342 * @param msgSupplier a supplier function that produces a message.
1343 * @param thrown a {@code Throwable} associated with log message;
1344 * can be {@code null}.
1345 *
1346 * @throws NullPointerException if {@code level} is {@code null}, or
1347 * {@code msgSupplier} is {@code null}.
1348 */
1349 public default void log(Level level, Supplier<String> msgSupplier,
1350 Throwable thrown) {
1351 Objects.requireNonNull(msgSupplier);
1352 if (isLoggable(Objects.requireNonNull(level))) {
1353 this.log(level, null, msgSupplier.get(), thrown);
1354 }
1355 }
1356
1357 /**
1358 * Logs a message with an optional list of parameters.
1359 *
1360 * @implSpec The default implementation for this method calls
1361 * {@code this.log(level, (ResourceBundle)null, format, params);}
1362 *
1363 * @param level one of the log message level identifiers.
1364 * @param format the string message format in {@link
1365 * java.text.MessageFormat} format, (or a key in the message
1366 * catalog, if this logger is a {@link
1367 * LoggerFinder#getLocalizedLogger(java.lang.String,
1368 * java.util.ResourceBundle, java.lang.Module) localized logger});
1369 * can be {@code null}.
1370 * @param params an optional list of parameters to the message (may be
1371 * none).
1372 *
1373 * @throws NullPointerException if {@code level} is {@code null}.
1374 */
1375 public default void log(Level level, String format, Object... params) {
1376 this.log(level, null, format, params);
1377 }
1378
1379 /**
1380 * Logs a localized message associated with a given throwable.
1381 *
1382 * If the given resource bundle is non-{@code null}, the {@code msg}
1383 * string is localized using the given resource bundle.
1384 * Otherwise the {@code msg} string is not localized.
1385 *
1386 * @param level the log message level.
1387 * @param bundle a resource bundle to localize {@code msg}; can be
1388 * {@code null}.
1389 * @param msg the string message (or a key in the message catalog,
1390 * if {@code bundle} is not {@code null}); can be {@code null}.
1391 * @param thrown a {@code Throwable} associated with the log message;
1392 * can be {@code null}.
1393 *
1394 * @throws NullPointerException if {@code level} is {@code null}.
1395 */
1396 public void log(Level level, ResourceBundle bundle, String msg,
1397 Throwable thrown);
1398
1399 /**
1400 * Logs a message with resource bundle and an optional list of
1401 * parameters.
1402 *
1403 * If the given resource bundle is non-{@code null}, the {@code format}
1404 * string is localized using the given resource bundle.
1405 * Otherwise the {@code format} string is not localized.
1406 *
1407 * @param level the log message level.
1408 * @param bundle a resource bundle to localize {@code format}; can be
1409 * {@code null}.
1410 * @param format the string message format in {@link
1411 * java.text.MessageFormat} format, (or a key in the message
1412 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1413 * @param params an optional list of parameters to the message (may be
1414 * none).
1415 *
1416 * @throws NullPointerException if {@code level} is {@code null}.
1417 */
1418 public void log(Level level, ResourceBundle bundle, String format,
1419 Object... params);
1420 }
1421
1422 /**
1423 * The {@code LoggerFinder} service is responsible for creating, managing,
1424 * and configuring loggers to the underlying framework it uses.
1425 *
1426 * A logger finder is a concrete implementation of this class that has a
1427 * zero-argument constructor and implements the abstract methods defined
1428 * by this class.
1429 * The loggers returned from a logger finder are capable of routing log
1430 * messages to the logging backend this provider supports.
1431 * A given invocation of the Java Runtime maintains a single
1432 * system-wide LoggerFinder instance that is loaded as follows:
1433 * <ul>
1434 * <li>First it finds any custom {@code LoggerFinder} provider
1435 * using the {@link java.util.ServiceLoader} facility with the
1436 * {@linkplain ClassLoader#getSystemClassLoader() system class
1437 * loader}.</li>
1438 * <li>If no {@code LoggerFinder} provider is found, the system default
1439 * {@code LoggerFinder} implementation will be used.</li>
1440 * </ul>
1441 * <p>
1442 * An application can replace the logging backend
1443 * <i>even when the java.logging module is present</i>, by simply providing
1444 * and declaring an implementation of the {@link LoggerFinder} service.
1445 * <p>
1446 * <b>Default Implementation</b>
1447 * <p>
1448 * The system default {@code LoggerFinder} implementation uses
1449 * {@code java.util.logging} as the backend framework when the
1450 * {@code java.logging} module is present.
1451 * It returns a {@linkplain System.Logger logger} instance
1452 * that will route log messages to a {@link java.util.logging.Logger
1453 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1454 * present, the default implementation will return a simple logger
1455 * instance that will route log messages of {@code INFO} level and above to
1456 * the console ({@code System.err}).
1457 * <p>
1458 * <b>Logging Configuration</b>
1459 * <p>
1460 * {@linkplain Logger Logger} instances obtained from the
1461 * {@code LoggerFinder} factory methods are not directly configurable by
1462 * the application. Configuration is the responsibility of the underlying
1463 * logging backend, and usually requires using APIs specific to that backend.
1464 * <p>For the default {@code LoggerFinder} implementation
1465 * using {@code java.util.logging} as its backend, refer to
1466 * {@link java.util.logging java.util.logging} for logging configuration.
1467 * For the default {@code LoggerFinder} implementation returning simple loggers
1468 * when the {@code java.logging} module is absent, the configuration
1469 * is implementation dependent.
1470 * <p>
1471 * Usually an application that uses a logging framework will log messages
1472 * through a logger facade defined (or supported) by that framework.
1473 * Applications that wish to use an external framework should log
1474 * through the facade associated with that framework.
1475 * <p>
1476 * A system class that needs to log messages will typically obtain
1477 * a {@link System.Logger} instance to route messages to the logging
1478 * framework selected by the application.
1479 * <p>
1480 * Libraries and classes that only need loggers to produce log messages
1481 * should not attempt to configure loggers by themselves, as that
1482 * would make them dependent from a specific implementation of the
1483 * {@code LoggerFinder} service.
1484 * <p>
1485 * In addition, when a security manager is present, loggers provided to
1486 * system classes should not be directly configurable through the logging
1487 * backend without requiring permissions.
1488 * <br>
1489 * It is the responsibility of the provider of
1490 * the concrete {@code LoggerFinder} implementation to ensure that
1491 * these loggers are not configured by untrusted code without proper
1492 * permission checks, as configuration performed on such loggers usually
1493 * affects all applications in the same Java Runtime.
1494 * <p>
1495 * <b>Message Levels and Mapping to backend levels</b>
1496 * <p>
1497 * A logger finder is responsible for mapping from a {@code
1498 * System.Logger.Level} to a level supported by the logging backend it uses.
1499 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1500 * maps {@code System.Logger} levels to
1501 * {@linkplain java.util.logging.Level java.util.logging} levels
1502 * of corresponding severity - as described in {@link Logger.Level
1503 * Logger.Level}.
1504 *
1505 * @see java.lang.System
1506 * @see java.lang.System.Logger
1507 *
1508 * @since 9
1509 */
1510 public static abstract class LoggerFinder {
1511 /**
1512 * The {@code RuntimePermission("loggerFinder")} is
1513 * necessary to subclass and instantiate the {@code LoggerFinder} class,
1514 * as well as to obtain loggers from an instance of that class.
1515 */
1516 static final RuntimePermission LOGGERFINDER_PERMISSION =
1517 new RuntimePermission("loggerFinder");
1518
1519 /**
1520 * Creates a new instance of {@code LoggerFinder}.
1521 *
1522 * @implNote It is recommended that a {@code LoggerFinder} service
1523 * implementation does not perform any heavy initialization in its
1524 * constructor, in order to avoid possible risks of deadlock or class
1525 * loading cycles during the instantiation of the service provider.
1526 *
1527 * @throws SecurityException if a security manager is present and its
1528 * {@code checkPermission} method doesn't allow the
1529 * {@code RuntimePermission("loggerFinder")}.
1530 */
1531 protected LoggerFinder() {
1532 this(checkPermission());
1533 }
1534
1535 private LoggerFinder(Void unused) {
1536 // nothing to do.
1537 }
1538
1539 private static Void checkPermission() {
1540 final SecurityManager sm = System.getSecurityManager();
1541 if (sm != null) {
1542 sm.checkPermission(LOGGERFINDER_PERMISSION);
1543 }
1544 return null;
1545 }
1546
1547 /**
1548 * Returns an instance of {@link Logger Logger}
1549 * for the given {@code module}.
1550 *
1551 * @param name the name of the logger.
1552 * @param module the module for which the logger is being requested.
1553 *
1554 * @return a {@link Logger logger} suitable for use within the given
1555 * module.
1556 * @throws NullPointerException if {@code name} is {@code null} or
1557 * {@code module} is {@code null}.
1558 * @throws SecurityException if a security manager is present and its
1559 * {@code checkPermission} method doesn't allow the
1560 * {@code RuntimePermission("loggerFinder")}.
1561 */
1562 public abstract Logger getLogger(String name, Module module);
1563
1564 /**
1565 * Returns a localizable instance of {@link Logger Logger}
1566 * for the given {@code module}.
1567 * The returned logger will use the provided resource bundle for
1568 * message localization.
1569 *
1570 * @implSpec By default, this method calls {@link
1571 * #getLogger(java.lang.String, java.lang.Module)
1572 * this.getLogger(name, module)} to obtain a logger, then wraps that
1573 * logger in a {@link Logger} instance where all methods that do not
1574 * take a {@link ResourceBundle} as parameter are redirected to one
1575 * which does - passing the given {@code bundle} for
1576 * localization. So for instance, a call to {@link
1577 * Logger#log(Logger.Level, String) Logger.log(Level.INFO, msg)}
1578 * will end up as a call to {@link
1579 * Logger#log(Logger.Level, ResourceBundle, String, Object...)
1580 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1581 * logger instance.
1582 * Note however that by default, string messages returned by {@link
1583 * java.util.function.Supplier Supplier<String>} will not be
1584 * localized, as it is assumed that such strings are messages which are
1585 * already constructed, rather than keys in a resource bundle.
1586 * <p>
1587 * An implementation of {@code LoggerFinder} may override this method,
1588 * for example, when the underlying logging backend provides its own
1589 * mechanism for localizing log messages, then such a
1590 * {@code LoggerFinder} would be free to return a logger
1591 * that makes direct use of the mechanism provided by the backend.
1592 *
1593 * @param name the name of the logger.
1594 * @param bundle a resource bundle; can be {@code null}.
1595 * @param module the module for which the logger is being requested.
1596 * @return an instance of {@link Logger Logger} which will use the
1597 * provided resource bundle for message localization.
1598 *
1599 * @throws NullPointerException if {@code name} is {@code null} or
1600 * {@code module} is {@code null}.
1601 * @throws SecurityException if a security manager is present and its
1602 * {@code checkPermission} method doesn't allow the
1603 * {@code RuntimePermission("loggerFinder")}.
1604 */
1605 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1606 Module module) {
1607 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1608 }
1609
1610 /**
1611 * Returns the {@code LoggerFinder} instance. There is one
1612 * single system-wide {@code LoggerFinder} instance in
1613 * the Java Runtime. See the class specification of how the
1614 * {@link LoggerFinder LoggerFinder} implementation is located and
1615 * loaded.
1616
1617 * @return the {@link LoggerFinder LoggerFinder} instance.
1618 * @throws SecurityException if a security manager is present and its
1619 * {@code checkPermission} method doesn't allow the
1620 * {@code RuntimePermission("loggerFinder")}.
1621 */
1622 public static LoggerFinder getLoggerFinder() {
1623 final SecurityManager sm = System.getSecurityManager();
1624 if (sm != null) {
1625 sm.checkPermission(LOGGERFINDER_PERMISSION);
1626 }
1627 return accessProvider();
1628 }
1629
1630
1631 private static volatile LoggerFinder service;
1632 static LoggerFinder accessProvider() {
1633 // We do not need to synchronize: LoggerFinderLoader will
1634 // always return the same instance, so if we don't have it,
1635 // just fetch it again.
1636 if (service == null) {
1637 PrivilegedAction<LoggerFinder> pa =
1638 () -> LoggerFinderLoader.getLoggerFinder();
1639 service = AccessController.doPrivileged(pa, null,
1640 LOGGERFINDER_PERMISSION);
1641 }
1642 return service;
1643 }
1644
1645 }
1646
1647
1648 /**
1649 * Returns an instance of {@link Logger Logger} for the caller's
1650 * use.
1651 *
1652 * @implSpec
1653 * Instances returned by this method route messages to loggers
1654 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1655 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1656 * {@code module} is the caller's module.
1657 * In cases where {@code System.getLogger} is called from a context where
1658 * there is no caller frame on the stack (e.g when called directly
1659 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1660 * To obtain a logger in such a context, use an auxiliary class that will
1661 * implicitly be identified as the caller, or use the system {@link
1662 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1663 * Note that doing the latter may eagerly initialize the underlying
1664 * logging system.
1665 *
1666 * @apiNote
1667 * This method may defer calling the {@link
1668 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1669 * LoggerFinder.getLogger} method to create an actual logger supplied by
1670 * the logging backend, for instance, to allow loggers to be obtained during
1671 * the system initialization time.
1672 *
1673 * @param name the name of the logger.
1674 * @return an instance of {@link Logger} that can be used by the calling
1675 * class.
1676 * @throws NullPointerException if {@code name} is {@code null}.
1677 * @throws IllegalCallerException if there is no Java caller frame on the
1678 * stack.
1679 *
1680 * @since 9
1681 */
1682 @CallerSensitive
1683 public static Logger getLogger(String name) {
1684 Objects.requireNonNull(name);
1685 final Class<?> caller = Reflection.getCallerClass();
1686 if (caller == null) {
1687 throw new IllegalCallerException("no caller frame");
1688 }
1689 return LazyLoggers.getLogger(name, caller.getModule());
1690 }
1691
1692 /**
1693 * Returns a localizable instance of {@link Logger
1694 * Logger} for the caller's use.
1695 * The returned logger will use the provided resource bundle for message
1696 * localization.
1697 *
1698 * @implSpec
1699 * The returned logger will perform message localization as specified
1700 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1701 * java.util.ResourceBundle, java.lang.Module)
1702 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1703 * {@code module} is the caller's module.
1704 * In cases where {@code System.getLogger} is called from a context where
1705 * there is no caller frame on the stack (e.g when called directly
1706 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1707 * To obtain a logger in such a context, use an auxiliary class that
1708 * will implicitly be identified as the caller, or use the system {@link
1709 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1710 * Note that doing the latter may eagerly initialize the underlying
1711 * logging system.
1712 *
1713 * @apiNote
1714 * This method is intended to be used after the system is fully initialized.
1715 * This method may trigger the immediate loading and initialization
1716 * of the {@link LoggerFinder} service, which may cause issues if the
1717 * Java Runtime is not ready to initialize the concrete service
1718 * implementation yet.
1719 * System classes which may be loaded early in the boot sequence and
1720 * need to log localized messages should create a logger using
1721 * {@link #getLogger(java.lang.String)} and then use the log methods that
1722 * take a resource bundle as parameter.
1723 *
1724 * @param name the name of the logger.
1725 * @param bundle a resource bundle.
1726 * @return an instance of {@link Logger} which will use the provided
1727 * resource bundle for message localization.
1728 * @throws NullPointerException if {@code name} is {@code null} or
1729 * {@code bundle} is {@code null}.
1730 * @throws IllegalCallerException if there is no Java caller frame on the
1731 * stack.
1732 *
1733 * @since 9
1734 */
1735 @CallerSensitive
1736 public static Logger getLogger(String name, ResourceBundle bundle) {
1737 final ResourceBundle rb = Objects.requireNonNull(bundle);
1738 Objects.requireNonNull(name);
1739 final Class<?> caller = Reflection.getCallerClass();
1740 if (caller == null) {
1741 throw new IllegalCallerException("no caller frame");
1742 }
1743 final SecurityManager sm = System.getSecurityManager();
1744 // We don't use LazyLoggers if a resource bundle is specified.
1745 // Bootstrap sensitive classes in the JDK do not use resource bundles
1746 // when logging. This could be revisited later, if it needs to.
1747 if (sm != null) {
1748 final PrivilegedAction<Logger> pa =
1749 () -> LoggerFinder.accessProvider()
1750 .getLocalizedLogger(name, rb, caller.getModule());
1751 return AccessController.doPrivileged(pa, null,
1752 LoggerFinder.LOGGERFINDER_PERMISSION);
1753 }
1754 return LoggerFinder.accessProvider()
1755 .getLocalizedLogger(name, rb, caller.getModule());
1756 }
1757
1758 /**
1759 * Terminates the currently running Java Virtual Machine. The
1760 * argument serves as a status code; by convention, a nonzero status
1761 * code indicates abnormal termination.
1762 * <p>
1763 * This method calls the {@code exit} method in class
1764 * {@code Runtime}. This method never returns normally.
1765 * <p>
1766 * The call {@code System.exit(n)} is effectively equivalent to
1767 * the call:
1768 * <blockquote><pre>
1769 * Runtime.getRuntime().exit(n)
1770 * </pre></blockquote>
1771 *
1772 * @param status exit status.
1773 * @throws SecurityException
1774 * if a security manager exists and its {@code checkExit}
1775 * method doesn't allow exit with the specified status.
1776 * @see java.lang.Runtime#exit(int)
1777 */
1778 public static void exit(int status) {
1779 Runtime.getRuntime().exit(status);
1780 }
1781
1782 /**
1783 * Runs the garbage collector.
1784 *
1785 * Calling the {@code gc} method suggests that the Java Virtual
1786 * Machine expend effort toward recycling unused objects in order to
1787 * make the memory they currently occupy available for quick reuse.
1788 * When control returns from the method call, the Java Virtual
1789 * Machine has made a best effort to reclaim space from all discarded
1790 * objects.
1791 * <p>
1792 * The call {@code System.gc()} is effectively equivalent to the
1793 * call:
1794 * <blockquote><pre>
1795 * Runtime.getRuntime().gc()
1796 * </pre></blockquote>
1797 *
1798 * @see java.lang.Runtime#gc()
1799 */
1800 public static void gc() {
1801 Runtime.getRuntime().gc();
1802 }
1803
1804 /**
1805 * Runs the finalization methods of any objects pending finalization.
1806 *
1807 * Calling this method suggests that the Java Virtual Machine expend
1808 * effort toward running the {@code finalize} methods of objects
1809 * that have been found to be discarded but whose {@code finalize}
1810 * methods have not yet been run. When control returns from the
1811 * method call, the Java Virtual Machine has made a best effort to
1812 * complete all outstanding finalizations.
1813 * <p>
1814 * The call {@code System.runFinalization()} is effectively
1815 * equivalent to the call:
1816 * <blockquote><pre>
1817 * Runtime.getRuntime().runFinalization()
1818 * </pre></blockquote>
1819 *
1820 * @see java.lang.Runtime#runFinalization()
1821 */
1822 public static void runFinalization() {
1823 Runtime.getRuntime().runFinalization();
1824 }
1825
1826 /**
1827 * Loads the native library specified by the filename argument. The filename
1828 * argument must be an absolute path name.
1829 *
1830 * If the filename argument, when stripped of any platform-specific library
1831 * prefix, path, and file extension, indicates a library whose name is,
1832 * for example, L, and a native library called L is statically linked
1833 * with the VM, then the JNI_OnLoad_L function exported by the library
1834 * is invoked rather than attempting to load a dynamic library.
1835 * A filename matching the argument does not have to exist in the
1836 * file system.
1837 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1838 * for more details.
1839 *
1840 * Otherwise, the filename argument is mapped to a native library image in
1841 * an implementation-dependent manner.
1842 *
1843 * <p>
1844 * The call {@code System.load(name)} is effectively equivalent
1845 * to the call:
1846 * <blockquote><pre>
1847 * Runtime.getRuntime().load(name)
1848 * </pre></blockquote>
1849 *
1850 * @param filename the file to load.
1851 * @throws SecurityException if a security manager exists and its
1852 * {@code checkLink} method doesn't allow
1853 * loading of the specified dynamic library
1854 * @throws UnsatisfiedLinkError if either the filename is not an
1855 * absolute path name, the native library is not statically
1856 * linked with the VM, or the library cannot be mapped to
1857 * a native library image by the host system.
1858 * @throws NullPointerException if {@code filename} is {@code null}
1859 * @see java.lang.Runtime#load(java.lang.String)
1860 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1861 */
1862 @CallerSensitive
1863 public static void load(String filename) {
1864 Runtime.getRuntime().load0(Reflection.getCallerClass(), filename);
1865 }
1866
1867 /**
1868 * Loads the native library specified by the {@code libname}
1869 * argument. The {@code libname} argument must not contain any platform
1870 * specific prefix, file extension or path. If a native library
1871 * called {@code libname} is statically linked with the VM, then the
1872 * JNI_OnLoad_{@code libname} function exported by the library is invoked.
1873 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1874 * for more details.
1875 *
1876 * Otherwise, the libname argument is loaded from a system library
1877 * location and mapped to a native library image in an implementation-
1878 * dependent manner.
1879 * <p>
1880 * The call {@code System.loadLibrary(name)} is effectively
1881 * equivalent to the call
1882 * <blockquote><pre>
1883 * Runtime.getRuntime().loadLibrary(name)
1884 * </pre></blockquote>
1885 *
1886 * @param libname the name of the library.
1887 * @throws SecurityException if a security manager exists and its
1888 * {@code checkLink} method doesn't allow
1889 * loading of the specified dynamic library
1890 * @throws UnsatisfiedLinkError if either the libname argument
1891 * contains a file path, the native library is not statically
1892 * linked with the VM, or the library cannot be mapped to a
1893 * native library image by the host system.
1894 * @throws NullPointerException if {@code libname} is {@code null}
1895 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1896 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1897 */
1898 @CallerSensitive
1899 public static void loadLibrary(String libname) {
1900 Runtime.getRuntime().loadLibrary0(Reflection.getCallerClass(), libname);
1901 }
1902
1903 /**
1904 * Maps a library name into a platform-specific string representing
1905 * a native library.
1906 *
1907 * @param libname the name of the library.
1908 * @return a platform-dependent native library name.
1909 * @throws NullPointerException if {@code libname} is {@code null}
1910 * @see java.lang.System#loadLibrary(java.lang.String)
1911 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1912 * @since 1.2
1913 */
1914 public static native String mapLibraryName(String libname);
1915
1916 /**
1917 * Create PrintStream for stdout/err based on encoding.
1918 */
1919 private static PrintStream newPrintStream(FileOutputStream fos, String enc) {
1920 if (enc != null) {
1921 try {
1922 return new PrintStream(new BufferedOutputStream(fos, 128), true, enc);
1923 } catch (UnsupportedEncodingException uee) {}
1924 }
1925 return new PrintStream(new BufferedOutputStream(fos, 128), true);
1926 }
1927
1928 /**
1929 * Logs an exception/error at initialization time to stdout or stderr.
1930 *
1931 * @param printToStderr to print to stderr rather than stdout
1932 * @param printStackTrace to print the stack trace
1933 * @param msg the message to print before the exception, can be {@code null}
1934 * @param e the exception or error
1935 */
1936 private static void logInitException(boolean printToStderr,
1937 boolean printStackTrace,
1938 String msg,
1939 Throwable e) {
1940 if (VM.initLevel() < 1) {
1941 throw new InternalError("system classes not initialized");
1942 }
1943 PrintStream log = (printToStderr) ? err : out;
1944 if (msg != null) {
1945 log.println(msg);
1946 }
1947 if (printStackTrace) {
1948 e.printStackTrace(log);
1949 } else {
1950 log.println(e);
1951 for (Throwable suppressed : e.getSuppressed()) {
1952 log.println("Suppressed: " + suppressed);
1953 }
1954 Throwable cause = e.getCause();
1955 if (cause != null) {
1956 log.println("Caused by: " + cause);
1957 }
1958 }
1959 }
1960
1961 /**
1962 * Initialize the system class. Called after thread initialization.
1963 */
1964 private static void initPhase1() {
1965
1966 // VM might invoke JNU_NewStringPlatform() to set those encoding
1967 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1968 // during "props" initialization, in which it may need access, via
1969 // System.getProperty(), to the related system encoding property that
1970 // have been initialized (put into "props") at early stage of the
1971 // initialization. So make sure the "props" is available at the
1972 // very beginning of the initialization and all system properties to
1973 // be put into it directly.
1974 props = new Properties(84);
1975 initProperties(props); // initialized by the VM
1976
1977 // There are certain system configurations that may be controlled by
1978 // VM options such as the maximum amount of direct memory and
1979 // Integer cache size used to support the object identity semantics
1980 // of autoboxing. Typically, the library will obtain these values
1981 // from the properties set by the VM. If the properties are for
1982 // internal implementation use only, these properties should be
1983 // removed from the system properties.
1984 //
1985 // See java.lang.Integer.IntegerCache and the
1986 // VM.saveAndRemoveProperties method for example.
1987 //
1988 // Save a private copy of the system properties object that
1989 // can only be accessed by the internal implementation. Remove
1990 // certain system properties that are not intended for public access.
1991 VM.saveAndRemoveProperties(props);
1992
1993 lineSeparator = props.getProperty("line.separator");
1994 StaticProperty.javaHome(); // Load StaticProperty to cache the property values
1995 VersionProps.init();
1996
1997 FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
1998 FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
1999 FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
2000 setIn0(new BufferedInputStream(fdIn));
2001 setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
2002 setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
2003
2004 // Setup Java signal handlers for HUP, TERM, and INT (where available).
2005 Terminator.setup();
2006
2007 // Initialize any miscellaneous operating system settings that need to be
2008 // set for the class libraries. Currently this is no-op everywhere except
2009 // for Windows where the process-wide error mode is set before the java.io
2010 // classes are used.
2011 VM.initializeOSEnvironment();
2012
2013 // The main thread is not added to its thread group in the same
2014 // way as other threads; we must do it ourselves here.
2015 Thread current = Thread.currentThread();
2016 current.getThreadGroup().add(current);
2017
2018 // register shared secrets
2019 setJavaLangAccess();
2020
2021 // Subsystems that are invoked during initialization can invoke
2022 // VM.isBooted() in order to avoid doing things that should
2023 // wait until the VM is fully initialized. The initialization level
2024 // is incremented from 0 to 1 here to indicate the first phase of
2025 // initialization has completed.
2026 // IMPORTANT: Ensure that this remains the last initialization action!
2027 VM.initLevel(1);
2028 }
2029
2030 // @see #initPhase2()
2031 static ModuleLayer bootLayer;
2032
2033 /*
2034 * Invoked by VM. Phase 2 module system initialization.
2035 * Only classes in java.base can be loaded in this phase.
2036 *
2037 * @param printToStderr print exceptions to stderr rather than stdout
2038 * @param printStackTrace print stack trace when exception occurs
2039 *
2040 * @return JNI_OK for success, JNI_ERR for failure
2041 */
2042 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
2043 try {
2044 bootLayer = ModuleBootstrap.boot();
2045 } catch (Exception | Error e) {
2046 logInitException(printToStderr, printStackTrace,
2047 "Error occurred during initialization of boot layer", e);
2048 return -1; // JNI_ERR
2049 }
2050
2051 // module system initialized
2052 VM.initLevel(2);
2053
2054 return 0; // JNI_OK
2055 }
2056
2057 /*
2058 * Invoked by VM. Phase 3 is the final system initialization:
2059 * 1. set security manager
2060 * 2. set system class loader
2061 * 3. set TCCL
2062 *
2063 * This method must be called after the module system initialization.
2064 * The security manager and system class loader may be a custom class from
2065 * the application classpath or modulepath.
2066 */
2067 private static void initPhase3() {
2068 String smProp = System.getProperty("java.security.manager");
2069 if (smProp != null) {
2070 switch (smProp) {
2071 case "disallow":
2072 allowSecurityManager = NEVER;
2073 break;
2074 case "allow":
2075 allowSecurityManager = MAYBE;
2076 break;
2077 case "":
2078 case "default":
2079 setSecurityManager(new SecurityManager());
2080 allowSecurityManager = MAYBE;
2081 break;
2082 default:
2083 try {
2084 ClassLoader cl = ClassLoader.getBuiltinAppClassLoader();
2085 Class<?> c = Class.forName(smProp, false, cl);
2086 Constructor<?> ctor = c.getConstructor();
2087 // Must be a public subclass of SecurityManager with
2088 // a public no-arg constructor
2089 if (!SecurityManager.class.isAssignableFrom(c) ||
2090 !Modifier.isPublic(c.getModifiers()) ||
2091 !Modifier.isPublic(ctor.getModifiers())) {
2092 throw new Error("Could not create SecurityManager: "
2093 + ctor.toString());
2094 }
2095 // custom security manager may be in non-exported package
2096 ctor.setAccessible(true);
2097 SecurityManager sm = (SecurityManager) ctor.newInstance();
2098 setSecurityManager(sm);
2099 } catch (Exception e) {
2100 throw new InternalError("Could not create SecurityManager", e);
2101 }
2102 allowSecurityManager = MAYBE;
2103 }
2104 } else {
2105 allowSecurityManager = MAYBE;
2106 }
2107
2108 // initializing the system class loader
2109 VM.initLevel(3);
2110
2111 // system class loader initialized
2112 ClassLoader scl = ClassLoader.initSystemClassLoader();
2113
2114 // set TCCL
2115 Thread.currentThread().setContextClassLoader(scl);
2116
2117 // system is fully initialized
2118 VM.initLevel(4);
2119 }
2120
2121 private static void setJavaLangAccess() {
2122 // Allow privileged classes outside of java.lang
2123 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2124 public List<Method> getDeclaredPublicMethods(Class<?> klass, String name, Class<?>... parameterTypes) {
2125 return klass.getDeclaredPublicMethods(name, parameterTypes);
2126 }
2127 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2128 return klass.getConstantPool();
2129 }
2130 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2131 return klass.casAnnotationType(oldType, newType);
2132 }
2133 public AnnotationType getAnnotationType(Class<?> klass) {
2134 return klass.getAnnotationType();
2135 }
2136 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2137 return klass.getDeclaredAnnotationMap();
2138 }
2139 public byte[] getRawClassAnnotations(Class<?> klass) {
2140 return klass.getRawAnnotations();
2141 }
2142 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2143 return klass.getRawTypeAnnotations();
2144 }
2145 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2146 return Class.getExecutableTypeAnnotationBytes(executable);
2147 }
2148 public <E extends Enum<E>>
2149 E[] getEnumConstantsShared(Class<E> klass) {
2150 return klass.getEnumConstantsShared();
2151 }
2152 public void blockedOn(Interruptible b) {
2153 Thread.blockedOn(b);
2154 }
2155 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2156 Shutdown.add(slot, registerShutdownInProgress, hook);
2157 }
2158 public Thread newThreadWithAcc(Runnable target, AccessControlContext acc) {
2159 return new Thread(target, acc);
2160 }
2161 @SuppressWarnings("deprecation")
2162 public void invokeFinalize(Object o) throws Throwable {
2163 o.finalize();
2164 }
2165 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2166 return cl.createOrGetClassLoaderValueMap();
2167 }
2168 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2169 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2170 }
2171 public Class<?> findBootstrapClassOrNull(ClassLoader cl, String name) {
2172 return cl.findBootstrapClassOrNull(name);
2173 }
2174 public Package definePackage(ClassLoader cl, String name, Module module) {
2175 return cl.definePackage(name, module);
2176 }
2177 public String fastUUID(long lsb, long msb) {
2178 return Long.fastUUID(lsb, msb);
2179 }
2180 public void addNonExportedPackages(ModuleLayer layer) {
2181 SecurityManager.addNonExportedPackages(layer);
2182 }
2183 public void invalidatePackageAccessCache() {
2184 SecurityManager.invalidatePackageAccessCache();
2185 }
2186 public Module defineModule(ClassLoader loader,
2187 ModuleDescriptor descriptor,
2188 URI uri) {
2189 return new Module(null, loader, descriptor, uri);
2190 }
2191 public Module defineUnnamedModule(ClassLoader loader) {
2192 return new Module(loader);
2193 }
2194 public void addReads(Module m1, Module m2) {
2195 m1.implAddReads(m2);
2196 }
2197 public void addReadsAllUnnamed(Module m) {
2198 m.implAddReadsAllUnnamed();
2199 }
2200 public void addExports(Module m, String pn, Module other) {
2201 m.implAddExports(pn, other);
2202 }
2203 public void addExportsToAllUnnamed(Module m, String pn) {
2204 m.implAddExportsToAllUnnamed(pn);
2205 }
2206 public void addOpens(Module m, String pn, Module other) {
2207 m.implAddOpens(pn, other);
2208 }
2209 public void addOpensToAllUnnamed(Module m, String pn) {
2210 m.implAddOpensToAllUnnamed(pn);
2211 }
2212 public void addOpensToAllUnnamed(Module m, Iterator<String> packages) {
2213 m.implAddOpensToAllUnnamed(packages);
2214 }
2215 public void addUses(Module m, Class<?> service) {
2216 m.implAddUses(service);
2217 }
2218 public boolean isReflectivelyExported(Module m, String pn, Module other) {
2219 return m.isReflectivelyExported(pn, other);
2220 }
2221 public boolean isReflectivelyOpened(Module m, String pn, Module other) {
2222 return m.isReflectivelyOpened(pn, other);
2223 }
2224 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2225 return layer.getServicesCatalog();
2226 }
2227 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2228 return layer.layers();
2229 }
2230 public Stream<ModuleLayer> layers(ClassLoader loader) {
2231 return ModuleLayer.layers(loader);
2232 }
2233
2234 public String newStringNoRepl(byte[] bytes, Charset cs) throws CharacterCodingException {
2235 return StringCoding.newStringNoRepl(bytes, cs);
2236 }
2237
2238 public byte[] getBytesNoRepl(String s, Charset cs) throws CharacterCodingException {
2239 return StringCoding.getBytesNoRepl(s, cs);
2240 }
2241
2242 public String newStringUTF8NoRepl(byte[] bytes, int off, int len) {
2243 return StringCoding.newStringUTF8NoRepl(bytes, off, len);
2244 }
2245
2246 public byte[] getBytesUTF8NoRepl(String s) {
2247 return StringCoding.getBytesUTF8NoRepl(s);
2248 }
2249
2250 public void setCause(Throwable t, Throwable cause) {
2251 t.setCause(cause);
2252 }
2253 });
2254 }
2255 }