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 sun.reflect.annotation.AnnotationType;
76 import sun.nio.ch.Interruptible;
77 import sun.security.util.SecurityConstants;
78
79 /**
80 * The {@code System} class contains several useful class fields
81 * and methods. It cannot be instantiated.
82 *
83 * Among the facilities provided by the {@code System} class
84 * are standard input, standard output, and error output streams;
85 * access to externally defined properties and environment
86 * variables; a means of loading files and libraries; and a utility
87 * method for quickly copying a portion of an array.
88 *
89 * @since 1.0
90 */
91 public final class System {
92 /* Register the natives via the static initializer.
93 *
94 * VM will invoke the initializeSystemClass method to complete
95 * the initialization for this class separated from clinit.
96 * Note that to use properties set by the VM, see the constraints
97 * described in the initializeSystemClass method.
98 */
99 private static native void registerNatives();
100 static {
101 registerNatives();
102 }
103
104 /** Don't let anyone instantiate this class */
105 private System() {
106 }
107
108 /**
109 * The "standard" input stream. This stream is already
110 * open and ready to supply input data. Typically this stream
111 * corresponds to keyboard input or another input source specified by
112 * the host environment or user.
113 */
114 public static final InputStream in = null;
115
116 /**
117 * The "standard" output stream. This stream is already
118 * open and ready to accept output data. Typically this stream
119 * corresponds to display output or another output destination
120 * specified by the host environment or user.
121 * <p>
122 * For simple stand-alone Java applications, a typical way to write
123 * a line of output data is:
124 * <blockquote><pre>
125 * System.out.println(data)
126 * </pre></blockquote>
127 * <p>
128 * See the {@code println} methods in class {@code PrintStream}.
129 *
130 * @see java.io.PrintStream#println()
131 * @see java.io.PrintStream#println(boolean)
132 * @see java.io.PrintStream#println(char)
133 * @see java.io.PrintStream#println(char[])
134 * @see java.io.PrintStream#println(double)
135 * @see java.io.PrintStream#println(float)
136 * @see java.io.PrintStream#println(int)
137 * @see java.io.PrintStream#println(long)
138 * @see java.io.PrintStream#println(java.lang.Object)
139 * @see java.io.PrintStream#println(java.lang.String)
140 */
141 public static final PrintStream out = null;
142
143 /**
144 * The "standard" error output stream. This stream is already
145 * open and ready to accept output data.
146 * <p>
147 * Typically this stream corresponds to display output or another
148 * output destination specified by the host environment or user. By
149 * convention, this output stream is used to display error messages
150 * or other information that should come to the immediate attention
151 * of a user even if the principal output stream, the value of the
152 * variable {@code out}, has been redirected to a file or other
153 * destination that is typically not continuously monitored.
154 */
155 public static final PrintStream err = null;
156
157 /* The security manager for the system.
158 */
159 private static volatile SecurityManager security;
160
161 /**
162 * Reassigns the "standard" input stream.
163 *
164 * First, if there is a security manager, its {@code checkPermission}
165 * method is called with a {@code RuntimePermission("setIO")} permission
166 * to see if it's ok to reassign the "standard" input stream.
167 *
168 * @param in the new standard input stream.
169 *
170 * @throws SecurityException
171 * if a security manager exists and its
172 * {@code checkPermission} method doesn't allow
173 * reassigning of the standard input stream.
174 *
175 * @see SecurityManager#checkPermission
176 * @see java.lang.RuntimePermission
177 *
178 * @since 1.1
179 */
180 public static void setIn(InputStream in) {
181 checkIO();
182 setIn0(in);
183 }
184
185 /**
186 * Reassigns the "standard" output stream.
187 *
188 * First, if there is a security manager, its {@code checkPermission}
189 * method is called with a {@code RuntimePermission("setIO")} permission
190 * to see if it's ok to reassign the "standard" output stream.
191 *
192 * @param out the new standard output stream
193 *
194 * @throws SecurityException
195 * if a security manager exists and its
196 * {@code checkPermission} method doesn't allow
197 * reassigning of the standard output stream.
198 *
199 * @see SecurityManager#checkPermission
200 * @see java.lang.RuntimePermission
201 *
202 * @since 1.1
203 */
204 public static void setOut(PrintStream out) {
205 checkIO();
206 setOut0(out);
207 }
208
209 /**
210 * Reassigns the "standard" error output stream.
211 *
212 * First, if there is a security manager, its {@code checkPermission}
213 * method is called with a {@code RuntimePermission("setIO")} permission
214 * to see if it's ok to reassign the "standard" error output stream.
215 *
216 * @param err the new standard error output stream.
217 *
218 * @throws SecurityException
219 * if a security manager exists and its
220 * {@code checkPermission} method doesn't allow
221 * reassigning of the standard error output stream.
222 *
223 * @see SecurityManager#checkPermission
224 * @see java.lang.RuntimePermission
225 *
226 * @since 1.1
227 */
228 public static void setErr(PrintStream err) {
229 checkIO();
230 setErr0(err);
231 }
232
233 private static volatile Console cons;
234 /**
235 * Returns the unique {@link java.io.Console Console} object associated
236 * with the current Java virtual machine, if any.
237 *
238 * @return The system console, if any, otherwise {@code null}.
239 *
240 * @since 1.6
241 */
242 public static Console console() {
243 Console c;
244 if ((c = cons) == null) {
245 synchronized (System.class) {
246 if ((c = cons) == null) {
247 cons = c = SharedSecrets.getJavaIOAccess().console();
248 }
249 }
250 }
251 return c;
252 }
253
254 /**
255 * Returns the channel inherited from the entity that created this
256 * Java virtual machine.
257 *
258 * This method returns the channel obtained by invoking the
259 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
260 * inheritedChannel} method of the system-wide default
261 * {@link java.nio.channels.spi.SelectorProvider} object.
262 *
263 * <p> In addition to the network-oriented channels described in
264 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
265 * inheritedChannel}, this method may return other kinds of
266 * channels in the future.
267 *
268 * @return The inherited channel, if any, otherwise {@code null}.
269 *
270 * @throws IOException
271 * If an I/O error occurs
272 *
273 * @throws SecurityException
274 * If a security manager is present and it does not
275 * permit access to the channel.
276 *
277 * @since 1.5
278 */
279 public static Channel inheritedChannel() throws IOException {
280 return SelectorProvider.provider().inheritedChannel();
281 }
282
283 private static void checkIO() {
284 SecurityManager sm = getSecurityManager();
285 if (sm != null) {
286 sm.checkPermission(new RuntimePermission("setIO"));
287 }
288 }
289
290 private static native void setIn0(InputStream in);
291 private static native void setOut0(PrintStream out);
292 private static native void setErr0(PrintStream err);
293
294 /**
295 * Sets the System security.
296 *
297 * If there is a security manager already installed, this method first
298 * calls the security manager's {@code checkPermission} method
299 * with a {@code RuntimePermission("setSecurityManager")}
300 * permission to ensure it's ok to replace the existing
301 * security manager.
302 * This may result in throwing a {@code SecurityException}.
303 *
304 * <p> Otherwise, the argument is established as the current
305 * security manager. If the argument is {@code null} and no
306 * security manager has been established, then no action is taken and
307 * the method simply returns.
308 *
309 * @param s the security manager.
310 * @throws SecurityException if the security manager has already
311 * been set and its {@code checkPermission} method
312 * doesn't allow it to be replaced.
313 * @see #getSecurityManager
314 * @see SecurityManager#checkPermission
315 * @see java.lang.RuntimePermission
316 */
317 public static void setSecurityManager(final SecurityManager s) {
318 if (security == null) {
319 // ensure image reader is initialized
320 Object.class.getResource("java/lang/ANY");
321 }
322 if (s != null) {
323 try {
324 s.checkPackageAccess("java.lang");
325 } catch (Exception e) {
326 // no-op
327 }
328 }
329 setSecurityManager0(s);
330 }
331
332 private static synchronized
333 void setSecurityManager0(final SecurityManager s) {
334 SecurityManager sm = getSecurityManager();
335 if (sm != null) {
336 // ask the currently installed security manager if we
337 // can replace it.
338 sm.checkPermission(new RuntimePermission
339 ("setSecurityManager"));
340 }
341
342 if ((s != null) && (s.getClass().getClassLoader() != null)) {
343 // New security manager class is not on bootstrap classpath.
344 // Cause policy to get initialized before we install the new
345 // security manager, in order to prevent infinite loops when
346 // trying to initialize the policy (which usually involves
347 // accessing some security and/or system properties, which in turn
348 // calls the installed security manager's checkPermission method
349 // which will loop infinitely if there is a non-system class
350 // (in this case: the new security manager class) on the stack).
351 AccessController.doPrivileged(new PrivilegedAction<>() {
352 public Object run() {
353 s.getClass().getProtectionDomain().implies
354 (SecurityConstants.ALL_PERMISSION);
355 return null;
356 }
357 });
358 }
359
360 security = s;
361 }
362
363 /**
364 * Gets the system security interface.
365 *
366 * @return if a security manager has already been established for the
367 * current application, then that security manager is returned;
368 * otherwise, {@code null} is returned.
369 * @see #setSecurityManager
370 */
371 public static SecurityManager getSecurityManager() {
372 return security;
373 }
374
375 /**
376 * Returns the current time in milliseconds. Note that
377 * while the unit of time of the return value is a millisecond,
378 * the granularity of the value depends on the underlying
379 * operating system and may be larger. For example, many
380 * operating systems measure time in units of tens of
381 * milliseconds.
382 *
383 * <p> See the description of the class {@code Date} for
384 * a discussion of slight discrepancies that may arise between
385 * "computer time" and coordinated universal time (UTC).
386 *
387 * @return the difference, measured in milliseconds, between
388 * the current time and midnight, January 1, 1970 UTC.
389 * @see java.util.Date
390 */
391 @HotSpotIntrinsicCandidate
392 public static native long currentTimeMillis();
393
394 /**
395 * Returns the current value of the running Java Virtual Machine's
396 * high-resolution time source, in nanoseconds.
397 *
398 * This method can only be used to measure elapsed time and is
399 * not related to any other notion of system or wall-clock time.
400 * The value returned represents nanoseconds since some fixed but
401 * arbitrary <i>origin</i> time (perhaps in the future, so values
402 * may be negative). The same origin is used by all invocations of
403 * this method in an instance of a Java virtual machine; other
404 * virtual machine instances are likely to use a different origin.
405 *
406 * <p>This method provides nanosecond precision, but not necessarily
407 * nanosecond resolution (that is, how frequently the value changes)
408 * - no guarantees are made except that the resolution is at least as
409 * good as that of {@link #currentTimeMillis()}.
410 *
411 * <p>Differences in successive calls that span greater than
412 * approximately 292 years (2<sup>63</sup> nanoseconds) will not
413 * correctly compute elapsed time due to numerical overflow.
414 *
415 * <p>The values returned by this method become meaningful only when
416 * the difference between two such values, obtained within the same
417 * instance of a Java virtual machine, is computed.
418 *
419 * <p>For example, to measure how long some code takes to execute:
420 * <pre> {@code
421 * long startTime = System.nanoTime();
422 * // ... the code being measured ...
423 * long elapsedNanos = System.nanoTime() - startTime;}</pre>
424 *
425 * <p>To compare elapsed time against a timeout, use <pre> {@code
426 * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
427 * instead of <pre> {@code
428 * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
429 * because of the possibility of numerical overflow.
430 *
431 * @return the current value of the running Java Virtual Machine's
432 * high-resolution time source, in nanoseconds
433 * @since 1.5
434 */
435 @HotSpotIntrinsicCandidate
436 public static native long nanoTime();
437
438 /**
439 * Copies an array from the specified source array, beginning at the
440 * specified position, to the specified position of the destination array.
441 * A subsequence of array components are copied from the source
442 * array referenced by {@code src} to the destination array
443 * referenced by {@code dest}. The number of components copied is
444 * equal to the {@code length} argument. The components at
445 * positions {@code srcPos} through
446 * {@code srcPos+length-1} in the source array are copied into
447 * positions {@code destPos} through
448 * {@code destPos+length-1}, respectively, of the destination
449 * array.
450 * <p>
451 * If the {@code src} and {@code dest} arguments refer to the
452 * same array object, then the copying is performed as if the
453 * components at positions {@code srcPos} through
454 * {@code srcPos+length-1} were first copied to a temporary
455 * array with {@code length} components and then the contents of
456 * the temporary array were copied into positions
457 * {@code destPos} through {@code destPos+length-1} of the
458 * destination array.
459 * <p>
460 * If {@code dest} is {@code null}, then a
461 * {@code NullPointerException} is thrown.
462 * <p>
463 * If {@code src} is {@code null}, then a
464 * {@code NullPointerException} is thrown and the destination
465 * array is not modified.
466 * <p>
467 * Otherwise, if any of the following is true, an
468 * {@code ArrayStoreException} is thrown and the destination is
469 * not modified:
470 * <ul>
471 * <li>The {@code src} argument refers to an object that is not an
472 * array.
473 * <li>The {@code dest} argument refers to an object that is not an
474 * array.
475 * <li>The {@code src} argument and {@code dest} argument refer
476 * to arrays whose component types are different primitive types.
477 * <li>The {@code src} argument refers to an array with a primitive
478 * component type and the {@code dest} argument refers to an array
479 * with a reference component type.
480 * <li>The {@code src} argument refers to an array with a reference
481 * component type and the {@code dest} argument refers to an array
482 * with a primitive component type.
483 * </ul>
484 * <p>
485 * Otherwise, if any of the following is true, an
486 * {@code IndexOutOfBoundsException} is
487 * thrown and the destination is not modified:
488 * <ul>
489 * <li>The {@code srcPos} argument is negative.
490 * <li>The {@code destPos} argument is negative.
491 * <li>The {@code length} argument is negative.
492 * <li>{@code srcPos+length} is greater than
493 * {@code src.length}, the length of the source array.
494 * <li>{@code destPos+length} is greater than
495 * {@code dest.length}, the length of the destination array.
496 * </ul>
497 * <p>
498 * Otherwise, if any actual component of the source array from
499 * position {@code srcPos} through
500 * {@code srcPos+length-1} cannot be converted to the component
501 * type of the destination array by assignment conversion, an
502 * {@code ArrayStoreException} is thrown. In this case, let
503 * <b><i>k</i></b> be the smallest nonnegative integer less than
504 * length such that {@code src[srcPos+}<i>k</i>{@code ]}
505 * cannot be converted to the component type of the destination
506 * array; when the exception is thrown, source array components from
507 * positions {@code srcPos} through
508 * {@code srcPos+}<i>k</i>{@code -1}
509 * will already have been copied to destination array positions
510 * {@code destPos} through
511 * {@code destPos+}<i>k</I>{@code -1} and no other
512 * positions of the destination array will have been modified.
513 * (Because of the restrictions already itemized, this
514 * paragraph effectively applies only to the situation where both
515 * arrays have component types that are reference types.)
516 *
517 * @param src the source array.
518 * @param srcPos starting position in the source array.
519 * @param dest the destination array.
520 * @param destPos starting position in the destination data.
521 * @param length the number of array elements to be copied.
522 * @throws IndexOutOfBoundsException if copying would cause
523 * access of data outside array bounds.
524 * @throws ArrayStoreException if an element in the {@code src}
525 * array could not be stored into the {@code dest} array
526 * because of a type mismatch.
527 * @throws NullPointerException if either {@code src} or
528 * {@code dest} is {@code null}.
529 */
530 @HotSpotIntrinsicCandidate
531 public static native void arraycopy(Object src, int srcPos,
532 Object dest, int destPos,
533 int length);
534
535 /**
536 * Set bit atomically
537 * @param bits bits
538 * @param index index
539 */
540 @HotSpotIntrinsicCandidate
541 public static void setBit(byte[] bits, int index) {
542 throw new UnsupportedOperationException();
543 }
544
545 /**
546 * Clear bit atomically
547 * @param bits bits
548 * @param index index
549 */
550 @HotSpotIntrinsicCandidate
551 public static void clrBit(byte[] bits, int index) {
552 throw new UnsupportedOperationException();
553 }
554
555 /**
556 * Get bit
557 * @param bits bits
558 * @param index index
559 * @return value
560 */
561 public static boolean isBit(byte[] bits, int index) {
562 return ((bits[index>>3] >> (index & 7)) & 1) == 1;
563 }
564
565 /**
566 * Returns the same hash code for the given object as
567 * would be returned by the default method hashCode(),
568 * whether or not the given object's class overrides
569 * hashCode().
570 * The hash code for the null reference is zero.
571 *
572 * @param x object for which the hashCode is to be calculated
573 * @return the hashCode
574 * @since 1.1
575 * @see Object#hashCode
576 * @see java.util.Objects#hashCode(Object)
577 */
578 @HotSpotIntrinsicCandidate
579 public static native int identityHashCode(Object x);
580
581 /**
582 * System properties. The following properties are guaranteed to be defined:
583 * <dl>
584 * <dt>java.version <dd>Java version number
585 * <dt>java.version.date <dd>Java version date
586 * <dt>java.vendor <dd>Java vendor specific string
587 * <dt>java.vendor.url <dd>Java vendor URL
588 * <dt>java.vendor.version <dd>Java vendor version
589 * <dt>java.home <dd>Java installation directory
590 * <dt>java.class.version <dd>Java class version number
591 * <dt>java.class.path <dd>Java classpath
592 * <dt>os.name <dd>Operating System Name
593 * <dt>os.arch <dd>Operating System Architecture
594 * <dt>os.version <dd>Operating System Version
595 * <dt>file.separator <dd>File separator ("/" on Unix)
596 * <dt>path.separator <dd>Path separator (":" on Unix)
597 * <dt>line.separator <dd>Line separator ("\n" on Unix)
598 * <dt>user.name <dd>User account name
599 * <dt>user.home <dd>User home directory
600 * <dt>user.dir <dd>User's current working directory
601 * </dl>
602 */
603
604 private static Properties props;
605 private static native Properties initProperties(Properties props);
606
607 /**
608 * Determines the current system properties.
609 *
610 * First, if there is a security manager, its
611 * {@code checkPropertiesAccess} method is called with no
612 * arguments. This may result in a security exception.
613 * <p>
614 * The current set of system properties for use by the
615 * {@link #getProperty(String)} method is returned as a
616 * {@code Properties} object. If there is no current set of
617 * system properties, a set of system properties is first created and
618 * initialized. This set of system properties always includes values
619 * for the following keys:
620 * <table class="striped" style="text-align:left">
621 * <caption style="display:none">Shows property keys and associated values</caption>
622 * <thead>
623 * <tr><th scope="col">Key</th>
624 * <th scope="col">Description of Associated Value</th></tr>
625 * </thead>
626 * <tbody>
627 * <tr><th scope="row">{@code java.version}</th>
628 * <td>Java Runtime Environment version, which may be interpreted
629 * as a {@link Runtime.Version}</td></tr>
630 * <tr><th scope="row">{@code java.version.date}</th>
631 * <td>Java Runtime Environment version date, in ISO-8601 YYYY-MM-DD
632 * format, which may be interpreted as a {@link
633 * java.time.LocalDate}</td></tr>
634 * <tr><th scope="row">{@code java.vendor}</th>
635 * <td>Java Runtime Environment vendor</td></tr>
636 * <tr><th scope="row">{@code java.vendor.url}</th>
637 * <td>Java vendor URL</td></tr>
638 * <tr><th scope="row">{@code java.vendor.version}</th>
639 * <td>Java vendor version</td></tr>
640 * <tr><th scope="row">{@code java.home}</th>
641 * <td>Java installation directory</td></tr>
642 * <tr><th scope="row">{@code java.vm.specification.version}</th>
643 * <td>Java Virtual Machine specification version, whose value is the
644 * {@linkplain Runtime.Version#feature feature} element of the
645 * {@linkplain Runtime#version() runtime version}</td></tr>
646 * <tr><th scope="row">{@code java.vm.specification.vendor}</th>
647 * <td>Java Virtual Machine specification vendor</td></tr>
648 * <tr><th scope="row">{@code java.vm.specification.name}</th>
649 * <td>Java Virtual Machine specification name</td></tr>
650 * <tr><th scope="row">{@code java.vm.version}</th>
651 * <td>Java Virtual Machine implementation version which may be
652 * interpreted as a {@link Runtime.Version}</td></tr>
653 * <tr><th scope="row">{@code java.vm.vendor}</th>
654 * <td>Java Virtual Machine implementation vendor</td></tr>
655 * <tr><th scope="row">{@code java.vm.name}</th>
656 * <td>Java Virtual Machine implementation name</td></tr>
657 * <tr><th scope="row">{@code java.specification.version}</th>
658 * <td>Java Runtime Environment specification version, whose value is
659 * the {@linkplain Runtime.Version#feature feature} element of the
660 * {@linkplain Runtime#version() runtime version}</td></tr>
661 * <tr><th scope="row">{@code java.specification.vendor}</th>
662 * <td>Java Runtime Environment specification vendor</td></tr>
663 * <tr><th scope="row">{@code java.specification.name}</th>
664 * <td>Java Runtime Environment specification name</td></tr>
665 * <tr><th scope="row">{@code java.class.version}</th>
666 * <td>Java class format version number</td></tr>
667 * <tr><th scope="row">{@code java.class.path}</th>
668 * <td>Java class path (refer to
669 * {@link ClassLoader#getSystemClassLoader()} for details)</td></tr>
670 * <tr><th scope="row">{@code java.library.path}</th>
671 * <td>List of paths to search when loading libraries</td></tr>
672 * <tr><th scope="row">{@code java.io.tmpdir}</th>
673 * <td>Default temp file path</td></tr>
674 * <tr><th scope="row">{@code java.compiler}</th>
675 * <td>Name of JIT compiler to use</td></tr>
676 * <tr><th scope="row">{@code os.name}</th>
677 * <td>Operating system name</td></tr>
678 * <tr><th scope="row">{@code os.arch}</th>
679 * <td>Operating system architecture</td></tr>
680 * <tr><th scope="row">{@code os.version}</th>
681 * <td>Operating system version</td></tr>
682 * <tr><th scope="row">{@code file.separator}</th>
683 * <td>File separator ("/" on UNIX)</td></tr>
684 * <tr><th scope="row">{@code path.separator}</th>
685 * <td>Path separator (":" on UNIX)</td></tr>
686 * <tr><th scope="row">{@code line.separator}</th>
687 * <td>Line separator ("\n" on UNIX)</td></tr>
688 * <tr><th scope="row">{@code user.name}</th>
689 * <td>User's account name</td></tr>
690 * <tr><th scope="row">{@code user.home}</th>
691 * <td>User's home directory</td></tr>
692 * <tr><th scope="row">{@code user.dir}</th>
693 * <td>User's current working directory</td></tr>
694 * </tbody>
695 * </table>
696 * <p>
697 * Multiple paths in a system property value are separated by the path
698 * separator character of the platform.
699 * <p>
700 * Note that even if the security manager does not permit the
701 * {@code getProperties} operation, it may choose to permit the
702 * {@link #getProperty(String)} operation.
703 *
704 * @apiNote
705 * <strong>Changing a standard system property may have unpredictable results
706 * unless otherwise specified.</strong>
707 * Property values may be cached during initialization or on first use.
708 * Setting a standard property after initialization using {@link #getProperties()},
709 * {@link #setProperties(Properties)}, {@link #setProperty(String, String)}, or
710 * {@link #clearProperty(String)} may not have the desired effect.
711 *
712 * @implNote
713 * In addition to the standard system properties, the system
714 * properties may include the following keys:
715 * <table class="striped">
716 * <caption style="display:none">Shows property keys and associated values</caption>
717 * <thead>
718 * <tr><th scope="col">Key</th>
719 * <th scope="col">Description of Associated Value</th></tr>
720 * </thead>
721 * <tbody>
722 * <tr><th scope="row">{@code jdk.module.path}</th>
723 * <td>The application module path</td></tr>
724 * <tr><th scope="row">{@code jdk.module.upgrade.path}</th>
725 * <td>The upgrade module path</td></tr>
726 * <tr><th scope="row">{@code jdk.module.main}</th>
727 * <td>The module name of the initial/main module</td></tr>
728 * <tr><th scope="row">{@code jdk.module.main.class}</th>
729 * <td>The main class name of the initial module</td></tr>
730 * </tbody>
731 * </table>
732 *
733 * @return the system properties
734 * @throws SecurityException if a security manager exists and its
735 * {@code checkPropertiesAccess} method doesn't allow access
736 * to the system properties.
737 * @see #setProperties
738 * @see java.lang.SecurityException
739 * @see java.lang.SecurityManager#checkPropertiesAccess()
740 * @see java.util.Properties
741 */
742 public static Properties getProperties() {
743 SecurityManager sm = getSecurityManager();
744 if (sm != null) {
745 sm.checkPropertiesAccess();
746 }
747
748 return props;
749 }
750
751 /**
752 * Returns the system-dependent line separator string. It always
753 * returns the same value - the initial value of the {@linkplain
754 * #getProperty(String) system property} {@code line.separator}.
755 *
756 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
757 * Windows systems it returns {@code "\r\n"}.
758 *
759 * @return the system-dependent line separator string
760 * @since 1.7
761 */
762 public static String lineSeparator() {
763 return lineSeparator;
764 }
765
766 private static String lineSeparator;
767
768 /**
769 * Sets the system properties to the {@code Properties} argument.
770 *
771 * First, if there is a security manager, its
772 * {@code checkPropertiesAccess} method is called with no
773 * arguments. This may result in a security exception.
774 * <p>
775 * The argument becomes the current set of system properties for use
776 * by the {@link #getProperty(String)} method. If the argument is
777 * {@code null}, then the current set of system properties is
778 * forgotten.
779 *
780 * @apiNote
781 * <strong>Changing a standard system property may have unpredictable results
782 * unless otherwise specified</strong>.
783 * See {@linkplain #getProperties getProperties} for details.
784 *
785 * @param props the new system properties.
786 * @throws SecurityException if a security manager exists and its
787 * {@code checkPropertiesAccess} method doesn't allow access
788 * to the system properties.
789 * @see #getProperties
790 * @see java.util.Properties
791 * @see java.lang.SecurityException
792 * @see java.lang.SecurityManager#checkPropertiesAccess()
793 */
794 public static void setProperties(Properties props) {
795 SecurityManager sm = getSecurityManager();
796 if (sm != null) {
797 sm.checkPropertiesAccess();
798 }
799 if (props == null) {
800 props = new Properties();
801 initProperties(props);
802 }
803 System.props = props;
804 }
805
806 /**
807 * Gets the system property indicated by the specified key.
808 *
809 * First, if there is a security manager, its
810 * {@code checkPropertyAccess} method is called with the key as
811 * its argument. This may result in a SecurityException.
812 * <p>
813 * If there is no current set of system properties, a set of system
814 * properties is first created and initialized in the same manner as
815 * for the {@code getProperties} method.
816 *
817 * @apiNote
818 * <strong>Changing a standard system property may have unpredictable results
819 * unless otherwise specified</strong>.
820 * See {@linkplain #getProperties getProperties} for details.
821 *
822 * @param key the name of the system property.
823 * @return the string value of the system property,
824 * or {@code null} if there is no property with that key.
825 *
826 * @throws SecurityException if a security manager exists and its
827 * {@code checkPropertyAccess} method doesn't allow
828 * access to the specified system property.
829 * @throws NullPointerException if {@code key} is {@code null}.
830 * @throws IllegalArgumentException if {@code key} is empty.
831 * @see #setProperty
832 * @see java.lang.SecurityException
833 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
834 * @see java.lang.System#getProperties()
835 */
836 public static String getProperty(String key) {
837 checkKey(key);
838 SecurityManager sm = getSecurityManager();
839 if (sm != null) {
840 sm.checkPropertyAccess(key);
841 }
842
843 return props.getProperty(key);
844 }
845
846 /**
847 * Gets the system property indicated by the specified key.
848 *
849 * First, if there is a security manager, its
850 * {@code checkPropertyAccess} method is called with the
851 * {@code key} as its argument.
852 * <p>
853 * If there is no current set of system properties, a set of system
854 * properties is first created and initialized in the same manner as
855 * for the {@code getProperties} method.
856 *
857 * @param key the name of the system property.
858 * @param def a default value.
859 * @return the string value of the system property,
860 * or the default value if there is no property with that key.
861 *
862 * @throws SecurityException if a security manager exists and its
863 * {@code checkPropertyAccess} method doesn't allow
864 * access to the specified system property.
865 * @throws NullPointerException if {@code key} is {@code null}.
866 * @throws IllegalArgumentException if {@code key} is empty.
867 * @see #setProperty
868 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
869 * @see java.lang.System#getProperties()
870 */
871 public static String getProperty(String key, String def) {
872 checkKey(key);
873 SecurityManager sm = getSecurityManager();
874 if (sm != null) {
875 sm.checkPropertyAccess(key);
876 }
877
878 return props.getProperty(key, def);
879 }
880
881 /**
882 * Sets the system property indicated by the specified key.
883 *
884 * First, if a security manager exists, its
885 * {@code SecurityManager.checkPermission} method
886 * is called with a {@code PropertyPermission(key, "write")}
887 * permission. This may result in a SecurityException being thrown.
888 * If no exception is thrown, the specified property is set to the given
889 * value.
890 *
891 * @apiNote
892 * <strong>Changing a standard system property may have unpredictable results
893 * unless otherwise specified</strong>.
894 * See {@linkplain #getProperties getProperties} for details.
895 *
896 * @param key the name of the system property.
897 * @param value the value of the system property.
898 * @return the previous value of the system property,
899 * or {@code null} if it did not have one.
900 *
901 * @throws SecurityException if a security manager exists and its
902 * {@code checkPermission} method doesn't allow
903 * setting of the specified property.
904 * @throws NullPointerException if {@code key} or
905 * {@code value} is {@code null}.
906 * @throws IllegalArgumentException if {@code key} is empty.
907 * @see #getProperty
908 * @see java.lang.System#getProperty(java.lang.String)
909 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
910 * @see java.util.PropertyPermission
911 * @see SecurityManager#checkPermission
912 * @since 1.2
913 */
914 public static String setProperty(String key, String value) {
915 checkKey(key);
916 SecurityManager sm = getSecurityManager();
917 if (sm != null) {
918 sm.checkPermission(new PropertyPermission(key,
919 SecurityConstants.PROPERTY_WRITE_ACTION));
920 }
921
922 return (String) props.setProperty(key, value);
923 }
924
925 /**
926 * Removes the system property indicated by the specified key.
927 *
928 * First, if a security manager exists, its
929 * {@code SecurityManager.checkPermission} method
930 * is called with a {@code PropertyPermission(key, "write")}
931 * permission. This may result in a SecurityException being thrown.
932 * If no exception is thrown, the specified property is removed.
933 *
934 * @apiNote
935 * <strong>Changing a standard system property may have unpredictable results
936 * unless otherwise specified</strong>.
937 * See {@linkplain #getProperties getProperties} method for details.
938 *
939 * @param key the name of the system property to be removed.
940 * @return the previous string value of the system property,
941 * or {@code null} if there was no property with that key.
942 *
943 * @throws SecurityException if a security manager exists and its
944 * {@code checkPropertyAccess} method doesn't allow
945 * access to the specified system property.
946 * @throws NullPointerException if {@code key} is {@code null}.
947 * @throws IllegalArgumentException if {@code key} is empty.
948 * @see #getProperty
949 * @see #setProperty
950 * @see java.util.Properties
951 * @see java.lang.SecurityException
952 * @see java.lang.SecurityManager#checkPropertiesAccess()
953 * @since 1.5
954 */
955 public static String clearProperty(String key) {
956 checkKey(key);
957 SecurityManager sm = getSecurityManager();
958 if (sm != null) {
959 sm.checkPermission(new PropertyPermission(key, "write"));
960 }
961
962 return (String) props.remove(key);
963 }
964
965 private static void checkKey(String key) {
966 if (key == null) {
967 throw new NullPointerException("key can't be null");
968 }
969 if (key.equals("")) {
970 throw new IllegalArgumentException("key can't be empty");
971 }
972 }
973
974 /**
975 * Gets the value of the specified environment variable. An
976 * environment variable is a system-dependent external named
977 * value.
978 *
979 * <p>If a security manager exists, its
980 * {@link SecurityManager#checkPermission checkPermission}
981 * method is called with a
982 * {@code {@link RuntimePermission}("getenv."+name)}
983 * permission. This may result in a {@link SecurityException}
984 * being thrown. If no exception is thrown the value of the
985 * variable {@code name} is returned.
986 *
987 * <p><a id="EnvironmentVSSystemProperties"><i>System
988 * properties</i> and <i>environment variables</i></a> are both
989 * conceptually mappings between names and values. Both
990 * mechanisms can be used to pass user-defined information to a
991 * Java process. Environment variables have a more global effect,
992 * because they are visible to all descendants of the process
993 * which defines them, not just the immediate Java subprocess.
994 * They can have subtly different semantics, such as case
995 * insensitivity, on different operating systems. For these
996 * reasons, environment variables are more likely to have
997 * unintended side effects. It is best to use system properties
998 * where possible. Environment variables should be used when a
999 * global effect is desired, or when an external system interface
1000 * requires an environment variable (such as {@code PATH}).
1001 *
1002 * <p>On UNIX systems the alphabetic case of {@code name} is
1003 * typically significant, while on Microsoft Windows systems it is
1004 * typically not. For example, the expression
1005 * {@code System.getenv("FOO").equals(System.getenv("foo"))}
1006 * is likely to be true on Microsoft Windows.
1007 *
1008 * @param name the name of the environment variable
1009 * @return the string value of the variable, or {@code null}
1010 * if the variable is not defined in the system environment
1011 * @throws NullPointerException if {@code name} is {@code null}
1012 * @throws SecurityException
1013 * if a security manager exists and its
1014 * {@link SecurityManager#checkPermission checkPermission}
1015 * method doesn't allow access to the environment variable
1016 * {@code name}
1017 * @see #getenv()
1018 * @see ProcessBuilder#environment()
1019 */
1020 public static String getenv(String name) {
1021 SecurityManager sm = getSecurityManager();
1022 if (sm != null) {
1023 sm.checkPermission(new RuntimePermission("getenv."+name));
1024 }
1025
1026 return ProcessEnvironment.getenv(name);
1027 }
1028
1029
1030 /**
1031 * Returns an unmodifiable string map view of the current system environment.
1032 * The environment is a system-dependent mapping from names to
1033 * values which is passed from parent to child processes.
1034 *
1035 * <p>If the system does not support environment variables, an
1036 * empty map is returned.
1037 *
1038 * <p>The returned map will never contain null keys or values.
1039 * Attempting to query the presence of a null key or value will
1040 * throw a {@link NullPointerException}. Attempting to query
1041 * the presence of a key or value which is not of type
1042 * {@link String} will throw a {@link ClassCastException}.
1043 *
1044 * <p>The returned map and its collection views may not obey the
1045 * general contract of the {@link Object#equals} and
1046 * {@link Object#hashCode} methods.
1047 *
1048 * <p>The returned map is typically case-sensitive on all platforms.
1049 *
1050 * <p>If a security manager exists, its
1051 * {@link SecurityManager#checkPermission checkPermission}
1052 * method is called with a
1053 * {@code {@link RuntimePermission}("getenv.*")} permission.
1054 * This may result in a {@link SecurityException} being thrown.
1055 *
1056 * <p>When passing information to a Java subprocess,
1057 * <a href=#EnvironmentVSSystemProperties>system properties</a>
1058 * are generally preferred over environment variables.
1059 *
1060 * @return the environment as a map of variable names to values
1061 * @throws SecurityException
1062 * if a security manager exists and its
1063 * {@link SecurityManager#checkPermission checkPermission}
1064 * method doesn't allow access to the process environment
1065 * @see #getenv(String)
1066 * @see ProcessBuilder#environment()
1067 * @since 1.5
1068 */
1069 public static java.util.Map<String,String> getenv() {
1070 SecurityManager sm = getSecurityManager();
1071 if (sm != null) {
1072 sm.checkPermission(new RuntimePermission("getenv.*"));
1073 }
1074
1075 return ProcessEnvironment.getenv();
1076 }
1077
1078 /**
1079 * {@code System.Logger} instances log messages that will be
1080 * routed to the underlying logging framework the {@link System.LoggerFinder
1081 * LoggerFinder} uses.
1082 *
1083 * {@code System.Logger} instances are typically obtained from
1084 * the {@link java.lang.System System} class, by calling
1085 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
1086 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1087 * System.getLogger(loggerName, bundle)}.
1088 *
1089 * @see java.lang.System#getLogger(java.lang.String)
1090 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1091 * @see java.lang.System.LoggerFinder
1092 *
1093 * @since 9
1094 */
1095 public interface Logger {
1096
1097 /**
1098 * System {@linkplain Logger loggers} levels.
1099 *
1100 * A level has a {@linkplain #getName() name} and {@linkplain
1101 * #getSeverity() severity}.
1102 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
1103 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
1104 * by order of increasing severity.
1105 * <br>
1106 * {@link #ALL} and {@link #OFF}
1107 * are simple markers with severities mapped respectively to
1108 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
1109 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
1110 * <p>
1111 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
1112 * <p>
1113 * {@linkplain System.Logger.Level System logger levels} are mapped to
1114 * {@linkplain java.util.logging.Level java.util.logging levels}
1115 * of corresponding severity.
1116 * <br>The mapping is as follows:
1117 * <br><br>
1118 * <table class="striped">
1119 * <caption>System.Logger Severity Level Mapping</caption>
1120 * <thead>
1121 * <tr><th scope="col">System.Logger Levels</th>
1122 * <th scope="col">java.util.logging Levels</th>
1123 * </thead>
1124 * <tbody>
1125 * <tr><th scope="row">{@link Logger.Level#ALL ALL}</th>
1126 * <td>{@link java.util.logging.Level#ALL ALL}</td>
1127 * <tr><th scope="row">{@link Logger.Level#TRACE TRACE}</th>
1128 * <td>{@link java.util.logging.Level#FINER FINER}</td>
1129 * <tr><th scope="row">{@link Logger.Level#DEBUG DEBUG}</th>
1130 * <td>{@link java.util.logging.Level#FINE FINE}</td>
1131 * <tr><th scope="row">{@link Logger.Level#INFO INFO}</th>
1132 * <td>{@link java.util.logging.Level#INFO INFO}</td>
1133 * <tr><th scope="row">{@link Logger.Level#WARNING WARNING}</th>
1134 * <td>{@link java.util.logging.Level#WARNING WARNING}</td>
1135 * <tr><th scope="row">{@link Logger.Level#ERROR ERROR}</th>
1136 * <td>{@link java.util.logging.Level#SEVERE SEVERE}</td>
1137 * <tr><th scope="row">{@link Logger.Level#OFF OFF}</th>
1138 * <td>{@link java.util.logging.Level#OFF OFF}</td>
1139 * </tbody>
1140 * </table>
1141 *
1142 * @since 9
1143 *
1144 * @see java.lang.System.LoggerFinder
1145 * @see java.lang.System.Logger
1146 */
1147 public enum Level {
1148
1149 // for convenience, we're reusing java.util.logging.Level int values
1150 // the mapping logic in sun.util.logging.PlatformLogger depends
1151 // on this.
1152 /**
1153 * A marker to indicate that all levels are enabled.
1154 * This level {@linkplain #getSeverity() severity} is
1155 * {@link Integer#MIN_VALUE}.
1156 */
1157 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
1158 /**
1159 * {@code TRACE} level: usually used to log diagnostic information.
1160 * This level {@linkplain #getSeverity() severity} is
1161 * {@code 400}.
1162 */
1163 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1164 /**
1165 * {@code DEBUG} level: usually used to log debug information traces.
1166 * This level {@linkplain #getSeverity() severity} is
1167 * {@code 500}.
1168 */
1169 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1170 /**
1171 * {@code INFO} level: usually used to log information messages.
1172 * This level {@linkplain #getSeverity() severity} is
1173 * {@code 800}.
1174 */
1175 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1176 /**
1177 * {@code WARNING} level: usually used to log warning messages.
1178 * This level {@linkplain #getSeverity() severity} is
1179 * {@code 900}.
1180 */
1181 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1182 /**
1183 * {@code ERROR} level: usually used to log error messages.
1184 * This level {@linkplain #getSeverity() severity} is
1185 * {@code 1000}.
1186 */
1187 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1188 /**
1189 * A marker to indicate that all levels are disabled.
1190 * This level {@linkplain #getSeverity() severity} is
1191 * {@link Integer#MAX_VALUE}.
1192 */
1193 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1194
1195 private final int severity;
1196
1197 private Level(int severity) {
1198 this.severity = severity;
1199 }
1200
1201 /**
1202 * Returns the name of this level.
1203 * @return this level {@linkplain #name()}.
1204 */
1205 public final String getName() {
1206 return name();
1207 }
1208
1209 /**
1210 * Returns the severity of this level.
1211 * A higher severity means a more severe condition.
1212 * @return this level severity.
1213 */
1214 public final int getSeverity() {
1215 return severity;
1216 }
1217 }
1218
1219 /**
1220 * Returns the name of this logger.
1221 *
1222 * @return the logger name.
1223 */
1224 public String getName();
1225
1226 /**
1227 * Checks if a message of the given level would be logged by
1228 * this logger.
1229 *
1230 * @param level the log message level.
1231 * @return {@code true} if the given log message level is currently
1232 * being logged.
1233 *
1234 * @throws NullPointerException if {@code level} is {@code null}.
1235 */
1236 public boolean isLoggable(Level level);
1237
1238 /**
1239 * Logs a message.
1240 *
1241 * @implSpec The default implementation for this method calls
1242 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1243 *
1244 * @param level the log message level.
1245 * @param msg the string message (or a key in the message catalog, if
1246 * this logger is a {@link
1247 * LoggerFinder#getLocalizedLogger(java.lang.String,
1248 * java.util.ResourceBundle, java.lang.Module) localized logger});
1249 * can be {@code null}.
1250 *
1251 * @throws NullPointerException if {@code level} is {@code null}.
1252 */
1253 public default void log(Level level, String msg) {
1254 log(level, (ResourceBundle) null, msg, (Object[]) null);
1255 }
1256
1257 /**
1258 * Logs a lazily supplied message.
1259 *
1260 * If the logger is currently enabled for the given log message level
1261 * then a message is logged that is the result produced by the
1262 * given supplier function. Otherwise, the supplier is not operated on.
1263 *
1264 * @implSpec When logging is enabled for the given level, the default
1265 * implementation for this method calls
1266 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1267 *
1268 * @param level the log message level.
1269 * @param msgSupplier a supplier function that produces a message.
1270 *
1271 * @throws NullPointerException if {@code level} is {@code null},
1272 * or {@code msgSupplier} is {@code null}.
1273 */
1274 public default void log(Level level, Supplier<String> msgSupplier) {
1275 Objects.requireNonNull(msgSupplier);
1276 if (isLoggable(Objects.requireNonNull(level))) {
1277 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1278 }
1279 }
1280
1281 /**
1282 * Logs a message produced from the given object.
1283 *
1284 * If the logger is currently enabled for the given log message level then
1285 * a message is logged that, by default, is the result produced from
1286 * calling toString on the given object.
1287 * Otherwise, the object is not operated on.
1288 *
1289 * @implSpec When logging is enabled for the given level, the default
1290 * implementation for this method calls
1291 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1292 *
1293 * @param level the log message level.
1294 * @param obj the object to log.
1295 *
1296 * @throws NullPointerException if {@code level} is {@code null}, or
1297 * {@code obj} is {@code null}.
1298 */
1299 public default void log(Level level, Object obj) {
1300 Objects.requireNonNull(obj);
1301 if (isLoggable(Objects.requireNonNull(level))) {
1302 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1303 }
1304 }
1305
1306 /**
1307 * Logs a message associated with a given throwable.
1308 *
1309 * @implSpec The default implementation for this method calls
1310 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1311 *
1312 * @param level the log message level.
1313 * @param msg the string message (or a key in the message catalog, if
1314 * this logger is a {@link
1315 * LoggerFinder#getLocalizedLogger(java.lang.String,
1316 * java.util.ResourceBundle, java.lang.Module) localized logger});
1317 * can be {@code null}.
1318 * @param thrown a {@code Throwable} associated with the log message;
1319 * can be {@code null}.
1320 *
1321 * @throws NullPointerException if {@code level} is {@code null}.
1322 */
1323 public default void log(Level level, String msg, Throwable thrown) {
1324 this.log(level, null, msg, thrown);
1325 }
1326
1327 /**
1328 * Logs a lazily supplied message associated with a given throwable.
1329 *
1330 * If the logger is currently enabled for the given log message level
1331 * then a message is logged that is the result produced by the
1332 * given supplier function. Otherwise, the supplier is not operated on.
1333 *
1334 * @implSpec When logging is enabled for the given level, the default
1335 * implementation for this method calls
1336 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1337 *
1338 * @param level one of the log message level identifiers.
1339 * @param msgSupplier a supplier function that produces a message.
1340 * @param thrown a {@code Throwable} associated with log message;
1341 * can be {@code null}.
1342 *
1343 * @throws NullPointerException if {@code level} is {@code null}, or
1344 * {@code msgSupplier} is {@code null}.
1345 */
1346 public default void log(Level level, Supplier<String> msgSupplier,
1347 Throwable thrown) {
1348 Objects.requireNonNull(msgSupplier);
1349 if (isLoggable(Objects.requireNonNull(level))) {
1350 this.log(level, null, msgSupplier.get(), thrown);
1351 }
1352 }
1353
1354 /**
1355 * Logs a message with an optional list of parameters.
1356 *
1357 * @implSpec The default implementation for this method calls
1358 * {@code this.log(level, (ResourceBundle)null, format, params);}
1359 *
1360 * @param level one of the log message level identifiers.
1361 * @param format the string message format in {@link
1362 * java.text.MessageFormat} format, (or a key in the message
1363 * catalog, if this logger is a {@link
1364 * LoggerFinder#getLocalizedLogger(java.lang.String,
1365 * java.util.ResourceBundle, java.lang.Module) localized logger});
1366 * can be {@code null}.
1367 * @param params an optional list of parameters to the message (may be
1368 * none).
1369 *
1370 * @throws NullPointerException if {@code level} is {@code null}.
1371 */
1372 public default void log(Level level, String format, Object... params) {
1373 this.log(level, null, format, params);
1374 }
1375
1376 /**
1377 * Logs a localized message associated with a given throwable.
1378 *
1379 * If the given resource bundle is non-{@code null}, the {@code msg}
1380 * string is localized using the given resource bundle.
1381 * Otherwise the {@code msg} string is not localized.
1382 *
1383 * @param level the log message level.
1384 * @param bundle a resource bundle to localize {@code msg}; can be
1385 * {@code null}.
1386 * @param msg the string message (or a key in the message catalog,
1387 * if {@code bundle} is not {@code null}); can be {@code null}.
1388 * @param thrown a {@code Throwable} associated with the log message;
1389 * can be {@code null}.
1390 *
1391 * @throws NullPointerException if {@code level} is {@code null}.
1392 */
1393 public void log(Level level, ResourceBundle bundle, String msg,
1394 Throwable thrown);
1395
1396 /**
1397 * Logs a message with resource bundle and an optional list of
1398 * parameters.
1399 *
1400 * If the given resource bundle is non-{@code null}, the {@code format}
1401 * string is localized using the given resource bundle.
1402 * Otherwise the {@code format} string is not localized.
1403 *
1404 * @param level the log message level.
1405 * @param bundle a resource bundle to localize {@code format}; can be
1406 * {@code null}.
1407 * @param format the string message format in {@link
1408 * java.text.MessageFormat} format, (or a key in the message
1409 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1410 * @param params an optional list of parameters to the message (may be
1411 * none).
1412 *
1413 * @throws NullPointerException if {@code level} is {@code null}.
1414 */
1415 public void log(Level level, ResourceBundle bundle, String format,
1416 Object... params);
1417 }
1418
1419 /**
1420 * The {@code LoggerFinder} service is responsible for creating, managing,
1421 * and configuring loggers to the underlying framework it uses.
1422 *
1423 * A logger finder is a concrete implementation of this class that has a
1424 * zero-argument constructor and implements the abstract methods defined
1425 * by this class.
1426 * The loggers returned from a logger finder are capable of routing log
1427 * messages to the logging backend this provider supports.
1428 * A given invocation of the Java Runtime maintains a single
1429 * system-wide LoggerFinder instance that is loaded as follows:
1430 * <ul>
1431 * <li>First it finds any custom {@code LoggerFinder} provider
1432 * using the {@link java.util.ServiceLoader} facility with the
1433 * {@linkplain ClassLoader#getSystemClassLoader() system class
1434 * loader}.</li>
1435 * <li>If no {@code LoggerFinder} provider is found, the system default
1436 * {@code LoggerFinder} implementation will be used.</li>
1437 * </ul>
1438 * <p>
1439 * An application can replace the logging backend
1440 * <i>even when the java.logging module is present</i>, by simply providing
1441 * and declaring an implementation of the {@link LoggerFinder} service.
1442 * <p>
1443 * <b>Default Implementation</b>
1444 * <p>
1445 * The system default {@code LoggerFinder} implementation uses
1446 * {@code java.util.logging} as the backend framework when the
1447 * {@code java.logging} module is present.
1448 * It returns a {@linkplain System.Logger logger} instance
1449 * that will route log messages to a {@link java.util.logging.Logger
1450 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1451 * present, the default implementation will return a simple logger
1452 * instance that will route log messages of {@code INFO} level and above to
1453 * the console ({@code System.err}).
1454 * <p>
1455 * <b>Logging Configuration</b>
1456 * <p>
1457 * {@linkplain Logger Logger} instances obtained from the
1458 * {@code LoggerFinder} factory methods are not directly configurable by
1459 * the application. Configuration is the responsibility of the underlying
1460 * logging backend, and usually requires using APIs specific to that backend.
1461 * <p>For the default {@code LoggerFinder} implementation
1462 * using {@code java.util.logging} as its backend, refer to
1463 * {@link java.util.logging java.util.logging} for logging configuration.
1464 * For the default {@code LoggerFinder} implementation returning simple loggers
1465 * when the {@code java.logging} module is absent, the configuration
1466 * is implementation dependent.
1467 * <p>
1468 * Usually an application that uses a logging framework will log messages
1469 * through a logger facade defined (or supported) by that framework.
1470 * Applications that wish to use an external framework should log
1471 * through the facade associated with that framework.
1472 * <p>
1473 * A system class that needs to log messages will typically obtain
1474 * a {@link System.Logger} instance to route messages to the logging
1475 * framework selected by the application.
1476 * <p>
1477 * Libraries and classes that only need loggers to produce log messages
1478 * should not attempt to configure loggers by themselves, as that
1479 * would make them dependent from a specific implementation of the
1480 * {@code LoggerFinder} service.
1481 * <p>
1482 * In addition, when a security manager is present, loggers provided to
1483 * system classes should not be directly configurable through the logging
1484 * backend without requiring permissions.
1485 * <br>
1486 * It is the responsibility of the provider of
1487 * the concrete {@code LoggerFinder} implementation to ensure that
1488 * these loggers are not configured by untrusted code without proper
1489 * permission checks, as configuration performed on such loggers usually
1490 * affects all applications in the same Java Runtime.
1491 * <p>
1492 * <b>Message Levels and Mapping to backend levels</b>
1493 * <p>
1494 * A logger finder is responsible for mapping from a {@code
1495 * System.Logger.Level} to a level supported by the logging backend it uses.
1496 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1497 * maps {@code System.Logger} levels to
1498 * {@linkplain java.util.logging.Level java.util.logging} levels
1499 * of corresponding severity - as described in {@link Logger.Level
1500 * Logger.Level}.
1501 *
1502 * @see java.lang.System
1503 * @see java.lang.System.Logger
1504 *
1505 * @since 9
1506 */
1507 public static abstract class LoggerFinder {
1508 /**
1509 * The {@code RuntimePermission("loggerFinder")} is
1510 * necessary to subclass and instantiate the {@code LoggerFinder} class,
1511 * as well as to obtain loggers from an instance of that class.
1512 */
1513 static final RuntimePermission LOGGERFINDER_PERMISSION =
1514 new RuntimePermission("loggerFinder");
1515
1516 /**
1517 * Creates a new instance of {@code LoggerFinder}.
1518 *
1519 * @implNote It is recommended that a {@code LoggerFinder} service
1520 * implementation does not perform any heavy initialization in its
1521 * constructor, in order to avoid possible risks of deadlock or class
1522 * loading cycles during the instantiation of the service provider.
1523 *
1524 * @throws SecurityException if a security manager is present and its
1525 * {@code checkPermission} method doesn't allow the
1526 * {@code RuntimePermission("loggerFinder")}.
1527 */
1528 protected LoggerFinder() {
1529 this(checkPermission());
1530 }
1531
1532 private LoggerFinder(Void unused) {
1533 // nothing to do.
1534 }
1535
1536 private static Void checkPermission() {
1537 final SecurityManager sm = System.getSecurityManager();
1538 if (sm != null) {
1539 sm.checkPermission(LOGGERFINDER_PERMISSION);
1540 }
1541 return null;
1542 }
1543
1544 /**
1545 * Returns an instance of {@link Logger Logger}
1546 * for the given {@code module}.
1547 *
1548 * @param name the name of the logger.
1549 * @param module the module for which the logger is being requested.
1550 *
1551 * @return a {@link Logger logger} suitable for use within the given
1552 * module.
1553 * @throws NullPointerException if {@code name} is {@code null} or
1554 * {@code module} is {@code null}.
1555 * @throws SecurityException if a security manager is present and its
1556 * {@code checkPermission} method doesn't allow the
1557 * {@code RuntimePermission("loggerFinder")}.
1558 */
1559 public abstract Logger getLogger(String name, Module module);
1560
1561 /**
1562 * Returns a localizable instance of {@link Logger Logger}
1563 * for the given {@code module}.
1564 * The returned logger will use the provided resource bundle for
1565 * message localization.
1566 *
1567 * @implSpec By default, this method calls {@link
1568 * #getLogger(java.lang.String, java.lang.Module)
1569 * this.getLogger(name, module)} to obtain a logger, then wraps that
1570 * logger in a {@link Logger} instance where all methods that do not
1571 * take a {@link ResourceBundle} as parameter are redirected to one
1572 * which does - passing the given {@code bundle} for
1573 * localization. So for instance, a call to {@link
1574 * Logger#log(Logger.Level, String) Logger.log(Level.INFO, msg)}
1575 * will end up as a call to {@link
1576 * Logger#log(Logger.Level, ResourceBundle, String, Object...)
1577 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1578 * logger instance.
1579 * Note however that by default, string messages returned by {@link
1580 * java.util.function.Supplier Supplier<String>} will not be
1581 * localized, as it is assumed that such strings are messages which are
1582 * already constructed, rather than keys in a resource bundle.
1583 * <p>
1584 * An implementation of {@code LoggerFinder} may override this method,
1585 * for example, when the underlying logging backend provides its own
1586 * mechanism for localizing log messages, then such a
1587 * {@code LoggerFinder} would be free to return a logger
1588 * that makes direct use of the mechanism provided by the backend.
1589 *
1590 * @param name the name of the logger.
1591 * @param bundle a resource bundle; can be {@code null}.
1592 * @param module the module for which the logger is being requested.
1593 * @return an instance of {@link Logger Logger} which will use the
1594 * provided resource bundle for message localization.
1595 *
1596 * @throws NullPointerException if {@code name} is {@code null} or
1597 * {@code module} is {@code null}.
1598 * @throws SecurityException if a security manager is present and its
1599 * {@code checkPermission} method doesn't allow the
1600 * {@code RuntimePermission("loggerFinder")}.
1601 */
1602 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1603 Module module) {
1604 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1605 }
1606
1607 /**
1608 * Returns the {@code LoggerFinder} instance. There is one
1609 * single system-wide {@code LoggerFinder} instance in
1610 * the Java Runtime. See the class specification of how the
1611 * {@link LoggerFinder LoggerFinder} implementation is located and
1612 * loaded.
1613
1614 * @return the {@link LoggerFinder LoggerFinder} instance.
1615 * @throws SecurityException if a security manager is present and its
1616 * {@code checkPermission} method doesn't allow the
1617 * {@code RuntimePermission("loggerFinder")}.
1618 */
1619 public static LoggerFinder getLoggerFinder() {
1620 final SecurityManager sm = System.getSecurityManager();
1621 if (sm != null) {
1622 sm.checkPermission(LOGGERFINDER_PERMISSION);
1623 }
1624 return accessProvider();
1625 }
1626
1627
1628 private static volatile LoggerFinder service;
1629 static LoggerFinder accessProvider() {
1630 // We do not need to synchronize: LoggerFinderLoader will
1631 // always return the same instance, so if we don't have it,
1632 // just fetch it again.
1633 if (service == null) {
1634 PrivilegedAction<LoggerFinder> pa =
1635 () -> LoggerFinderLoader.getLoggerFinder();
1636 service = AccessController.doPrivileged(pa, null,
1637 LOGGERFINDER_PERMISSION);
1638 }
1639 return service;
1640 }
1641
1642 }
1643
1644
1645 /**
1646 * Returns an instance of {@link Logger Logger} for the caller's
1647 * use.
1648 *
1649 * @implSpec
1650 * Instances returned by this method route messages to loggers
1651 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1652 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1653 * {@code module} is the caller's module.
1654 * In cases where {@code System.getLogger} is called from a context where
1655 * there is no caller frame on the stack (e.g when called directly
1656 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1657 * To obtain a logger in such a context, use an auxiliary class that will
1658 * implicitly be identified as the caller, or use the system {@link
1659 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1660 * Note that doing the latter may eagerly initialize the underlying
1661 * logging system.
1662 *
1663 * @apiNote
1664 * This method may defer calling the {@link
1665 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1666 * LoggerFinder.getLogger} method to create an actual logger supplied by
1667 * the logging backend, for instance, to allow loggers to be obtained during
1668 * the system initialization time.
1669 *
1670 * @param name the name of the logger.
1671 * @return an instance of {@link Logger} that can be used by the calling
1672 * class.
1673 * @throws NullPointerException if {@code name} is {@code null}.
1674 * @throws IllegalCallerException if there is no Java caller frame on the
1675 * stack.
1676 *
1677 * @since 9
1678 */
1679 @CallerSensitive
1680 public static Logger getLogger(String name) {
1681 Objects.requireNonNull(name);
1682 final Class<?> caller = Reflection.getCallerClass();
1683 if (caller == null) {
1684 throw new IllegalCallerException("no caller frame");
1685 }
1686 return LazyLoggers.getLogger(name, caller.getModule());
1687 }
1688
1689 /**
1690 * Returns a localizable instance of {@link Logger
1691 * Logger} for the caller's use.
1692 * The returned logger will use the provided resource bundle for message
1693 * localization.
1694 *
1695 * @implSpec
1696 * The returned logger will perform message localization as specified
1697 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1698 * java.util.ResourceBundle, java.lang.Module)
1699 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1700 * {@code module} is the caller's module.
1701 * In cases where {@code System.getLogger} is called from a context where
1702 * there is no caller frame on the stack (e.g when called directly
1703 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1704 * To obtain a logger in such a context, use an auxiliary class that
1705 * will implicitly be identified as the caller, or use the system {@link
1706 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1707 * Note that doing the latter may eagerly initialize the underlying
1708 * logging system.
1709 *
1710 * @apiNote
1711 * This method is intended to be used after the system is fully initialized.
1712 * This method may trigger the immediate loading and initialization
1713 * of the {@link LoggerFinder} service, which may cause issues if the
1714 * Java Runtime is not ready to initialize the concrete service
1715 * implementation yet.
1716 * System classes which may be loaded early in the boot sequence and
1717 * need to log localized messages should create a logger using
1718 * {@link #getLogger(java.lang.String)} and then use the log methods that
1719 * take a resource bundle as parameter.
1720 *
1721 * @param name the name of the logger.
1722 * @param bundle a resource bundle.
1723 * @return an instance of {@link Logger} which will use the provided
1724 * resource bundle for message localization.
1725 * @throws NullPointerException if {@code name} is {@code null} or
1726 * {@code bundle} is {@code null}.
1727 * @throws IllegalCallerException if there is no Java caller frame on the
1728 * stack.
1729 *
1730 * @since 9
1731 */
1732 @CallerSensitive
1733 public static Logger getLogger(String name, ResourceBundle bundle) {
1734 final ResourceBundle rb = Objects.requireNonNull(bundle);
1735 Objects.requireNonNull(name);
1736 final Class<?> caller = Reflection.getCallerClass();
1737 if (caller == null) {
1738 throw new IllegalCallerException("no caller frame");
1739 }
1740 final SecurityManager sm = System.getSecurityManager();
1741 // We don't use LazyLoggers if a resource bundle is specified.
1742 // Bootstrap sensitive classes in the JDK do not use resource bundles
1743 // when logging. This could be revisited later, if it needs to.
1744 if (sm != null) {
1745 final PrivilegedAction<Logger> pa =
1746 () -> LoggerFinder.accessProvider()
1747 .getLocalizedLogger(name, rb, caller.getModule());
1748 return AccessController.doPrivileged(pa, null,
1749 LoggerFinder.LOGGERFINDER_PERMISSION);
1750 }
1751 return LoggerFinder.accessProvider()
1752 .getLocalizedLogger(name, rb, caller.getModule());
1753 }
1754
1755 /**
1756 * Terminates the currently running Java Virtual Machine. The
1757 * argument serves as a status code; by convention, a nonzero status
1758 * code indicates abnormal termination.
1759 * <p>
1760 * This method calls the {@code exit} method in class
1761 * {@code Runtime}. This method never returns normally.
1762 * <p>
1763 * The call {@code System.exit(n)} is effectively equivalent to
1764 * the call:
1765 * <blockquote><pre>
1766 * Runtime.getRuntime().exit(n)
1767 * </pre></blockquote>
1768 *
1769 * @param status exit status.
1770 * @throws SecurityException
1771 * if a security manager exists and its {@code checkExit}
1772 * method doesn't allow exit with the specified status.
1773 * @see java.lang.Runtime#exit(int)
1774 */
1775 public static void exit(int status) {
1776 Runtime.getRuntime().exit(status);
1777 }
1778
1779 /**
1780 * Runs the garbage collector.
1781 *
1782 * Calling the {@code gc} method suggests that the Java Virtual
1783 * Machine expend effort toward recycling unused objects in order to
1784 * make the memory they currently occupy available for quick reuse.
1785 * When control returns from the method call, the Java Virtual
1786 * Machine has made a best effort to reclaim space from all discarded
1787 * objects.
1788 * <p>
1789 * The call {@code System.gc()} is effectively equivalent to the
1790 * call:
1791 * <blockquote><pre>
1792 * Runtime.getRuntime().gc()
1793 * </pre></blockquote>
1794 *
1795 * @see java.lang.Runtime#gc()
1796 */
1797 public static void gc() {
1798 Runtime.getRuntime().gc();
1799 }
1800
1801 /**
1802 * Runs the finalization methods of any objects pending finalization.
1803 *
1804 * Calling this method suggests that the Java Virtual Machine expend
1805 * effort toward running the {@code finalize} methods of objects
1806 * that have been found to be discarded but whose {@code finalize}
1807 * methods have not yet been run. When control returns from the
1808 * method call, the Java Virtual Machine has made a best effort to
1809 * complete all outstanding finalizations.
1810 * <p>
1811 * The call {@code System.runFinalization()} is effectively
1812 * equivalent to the call:
1813 * <blockquote><pre>
1814 * Runtime.getRuntime().runFinalization()
1815 * </pre></blockquote>
1816 *
1817 * @see java.lang.Runtime#runFinalization()
1818 */
1819 public static void runFinalization() {
1820 Runtime.getRuntime().runFinalization();
1821 }
1822
1823 /**
1824 * Loads the native library specified by the filename argument. The filename
1825 * argument must be an absolute path name.
1826 *
1827 * If the filename argument, when stripped of any platform-specific library
1828 * prefix, path, and file extension, indicates a library whose name is,
1829 * for example, L, and a native library called L is statically linked
1830 * with the VM, then the JNI_OnLoad_L function exported by the library
1831 * is invoked rather than attempting to load a dynamic library.
1832 * A filename matching the argument does not have to exist in the
1833 * file system.
1834 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1835 * for more details.
1836 *
1837 * Otherwise, the filename argument is mapped to a native library image in
1838 * an implementation-dependent manner.
1839 *
1840 * <p>
1841 * The call {@code System.load(name)} is effectively equivalent
1842 * to the call:
1843 * <blockquote><pre>
1844 * Runtime.getRuntime().load(name)
1845 * </pre></blockquote>
1846 *
1847 * @param filename the file to load.
1848 * @throws SecurityException if a security manager exists and its
1849 * {@code checkLink} method doesn't allow
1850 * loading of the specified dynamic library
1851 * @throws UnsatisfiedLinkError if either the filename is not an
1852 * absolute path name, the native library is not statically
1853 * linked with the VM, or the library cannot be mapped to
1854 * a native library image by the host system.
1855 * @throws NullPointerException if {@code filename} is {@code null}
1856 * @see java.lang.Runtime#load(java.lang.String)
1857 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1858 */
1859 @CallerSensitive
1860 public static void load(String filename) {
1861 Runtime.getRuntime().load0(Reflection.getCallerClass(), filename);
1862 }
1863
1864 /**
1865 * Loads the native library specified by the {@code libname}
1866 * argument. The {@code libname} argument must not contain any platform
1867 * specific prefix, file extension or path. If a native library
1868 * called {@code libname} is statically linked with the VM, then the
1869 * JNI_OnLoad_{@code libname} function exported by the library is invoked.
1870 * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
1871 * for more details.
1872 *
1873 * Otherwise, the libname argument is loaded from a system library
1874 * location and mapped to a native library image in an implementation-
1875 * dependent manner.
1876 * <p>
1877 * The call {@code System.loadLibrary(name)} is effectively
1878 * equivalent to the call
1879 * <blockquote><pre>
1880 * Runtime.getRuntime().loadLibrary(name)
1881 * </pre></blockquote>
1882 *
1883 * @param libname the name of the library.
1884 * @throws SecurityException if a security manager exists and its
1885 * {@code checkLink} method doesn't allow
1886 * loading of the specified dynamic library
1887 * @throws UnsatisfiedLinkError if either the libname argument
1888 * contains a file path, the native library is not statically
1889 * linked with the VM, or the library cannot be mapped to a
1890 * native library image by the host system.
1891 * @throws NullPointerException if {@code libname} is {@code null}
1892 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1893 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1894 */
1895 @CallerSensitive
1896 public static void loadLibrary(String libname) {
1897 Runtime.getRuntime().loadLibrary0(Reflection.getCallerClass(), libname);
1898 }
1899
1900 /**
1901 * Maps a library name into a platform-specific string representing
1902 * a native library.
1903 *
1904 * @param libname the name of the library.
1905 * @return a platform-dependent native library name.
1906 * @throws NullPointerException if {@code libname} is {@code null}
1907 * @see java.lang.System#loadLibrary(java.lang.String)
1908 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1909 * @since 1.2
1910 */
1911 public static native String mapLibraryName(String libname);
1912
1913 /**
1914 * Create PrintStream for stdout/err based on encoding.
1915 */
1916 private static PrintStream newPrintStream(FileOutputStream fos, String enc) {
1917 if (enc != null) {
1918 try {
1919 return new PrintStream(new BufferedOutputStream(fos, 128), true, enc);
1920 } catch (UnsupportedEncodingException uee) {}
1921 }
1922 return new PrintStream(new BufferedOutputStream(fos, 128), true);
1923 }
1924
1925 /**
1926 * Logs an exception/error at initialization time to stdout or stderr.
1927 *
1928 * @param printToStderr to print to stderr rather than stdout
1929 * @param printStackTrace to print the stack trace
1930 * @param msg the message to print before the exception, can be {@code null}
1931 * @param e the exception or error
1932 */
1933 private static void logInitException(boolean printToStderr,
1934 boolean printStackTrace,
1935 String msg,
1936 Throwable e) {
1937 if (VM.initLevel() < 1) {
1938 throw new InternalError("system classes not initialized");
1939 }
1940 PrintStream log = (printToStderr) ? err : out;
1941 if (msg != null) {
1942 log.println(msg);
1943 }
1944 if (printStackTrace) {
1945 e.printStackTrace(log);
1946 } else {
1947 log.println(e);
1948 for (Throwable suppressed : e.getSuppressed()) {
1949 log.println("Suppressed: " + suppressed);
1950 }
1951 Throwable cause = e.getCause();
1952 if (cause != null) {
1953 log.println("Caused by: " + cause);
1954 }
1955 }
1956 }
1957
1958 /**
1959 * Initialize the system class. Called after thread initialization.
1960 */
1961 private static void initPhase1() {
1962
1963 // VM might invoke JNU_NewStringPlatform() to set those encoding
1964 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1965 // during "props" initialization, in which it may need access, via
1966 // System.getProperty(), to the related system encoding property that
1967 // have been initialized (put into "props") at early stage of the
1968 // initialization. So make sure the "props" is available at the
1969 // very beginning of the initialization and all system properties to
1970 // be put into it directly.
1971 props = new Properties(84);
1972 initProperties(props); // initialized by the VM
1973
1974 // There are certain system configurations that may be controlled by
1975 // VM options such as the maximum amount of direct memory and
1976 // Integer cache size used to support the object identity semantics
1977 // of autoboxing. Typically, the library will obtain these values
1978 // from the properties set by the VM. If the properties are for
1979 // internal implementation use only, these properties should be
1980 // removed from the system properties.
1981 //
1982 // See java.lang.Integer.IntegerCache and the
1983 // VM.saveAndRemoveProperties method for example.
1984 //
1985 // Save a private copy of the system properties object that
1986 // can only be accessed by the internal implementation. Remove
1987 // certain system properties that are not intended for public access.
1988 VM.saveAndRemoveProperties(props);
1989
1990 lineSeparator = props.getProperty("line.separator");
1991 StaticProperty.javaHome(); // Load StaticProperty to cache the property values
1992 VersionProps.init();
1993
1994 FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
1995 FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
1996 FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
1997 setIn0(new BufferedInputStream(fdIn));
1998 setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
1999 setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
2000
2001 // Setup Java signal handlers for HUP, TERM, and INT (where available).
2002 Terminator.setup();
2003
2004 // Initialize any miscellaneous operating system settings that need to be
2005 // set for the class libraries. Currently this is no-op everywhere except
2006 // for Windows where the process-wide error mode is set before the java.io
2007 // classes are used.
2008 VM.initializeOSEnvironment();
2009
2010 // The main thread is not added to its thread group in the same
2011 // way as other threads; we must do it ourselves here.
2012 Thread current = Thread.currentThread();
2013 current.getThreadGroup().add(current);
2014
2015 // register shared secrets
2016 setJavaLangAccess();
2017
2018 // Subsystems that are invoked during initialization can invoke
2019 // VM.isBooted() in order to avoid doing things that should
2020 // wait until the VM is fully initialized. The initialization level
2021 // is incremented from 0 to 1 here to indicate the first phase of
2022 // initialization has completed.
2023 // IMPORTANT: Ensure that this remains the last initialization action!
2024 VM.initLevel(1);
2025 }
2026
2027 // @see #initPhase2()
2028 static ModuleLayer bootLayer;
2029
2030 /*
2031 * Invoked by VM. Phase 2 module system initialization.
2032 * Only classes in java.base can be loaded in this phase.
2033 *
2034 * @param printToStderr print exceptions to stderr rather than stdout
2035 * @param printStackTrace print stack trace when exception occurs
2036 *
2037 * @return JNI_OK for success, JNI_ERR for failure
2038 */
2039 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
2040 try {
2041 bootLayer = ModuleBootstrap.boot();
2042 } catch (Exception | Error e) {
2043 logInitException(printToStderr, printStackTrace,
2044 "Error occurred during initialization of boot layer", e);
2045 return -1; // JNI_ERR
2046 }
2047
2048 // module system initialized
2049 VM.initLevel(2);
2050
2051 return 0; // JNI_OK
2052 }
2053
2054 /*
2055 * Invoked by VM. Phase 3 is the final system initialization:
2056 * 1. set security manager
2057 * 2. set system class loader
2058 * 3. set TCCL
2059 *
2060 * This method must be called after the module system initialization.
2061 * The security manager and system class loader may be custom class from
2062 * the application classpath or modulepath.
2063 */
2064 private static void initPhase3() {
2065 // set security manager
2066 String cn = System.getProperty("java.security.manager");
2067 if (cn != null) {
2068 if (cn.isEmpty() || "default".equals(cn)) {
2069 System.setSecurityManager(new SecurityManager());
2070 } else {
2071 try {
2072 Class<?> c = Class.forName(cn, false, ClassLoader.getBuiltinAppClassLoader());
2073 Constructor<?> ctor = c.getConstructor();
2074 // Must be a public subclass of SecurityManager with
2075 // a public no-arg constructor
2076 if (!SecurityManager.class.isAssignableFrom(c) ||
2077 !Modifier.isPublic(c.getModifiers()) ||
2078 !Modifier.isPublic(ctor.getModifiers())) {
2079 throw new Error("Could not create SecurityManager: " + ctor.toString());
2080 }
2081 // custom security manager implementation may be in unnamed module
2082 // or a named module but non-exported package
2083 ctor.setAccessible(true);
2084 SecurityManager sm = (SecurityManager) ctor.newInstance();
2085 System.setSecurityManager(sm);
2086 } catch (Exception e) {
2087 throw new Error("Could not create SecurityManager", e);
2088 }
2089 }
2090 }
2091
2092 // initializing the system class loader
2093 VM.initLevel(3);
2094
2095 // system class loader initialized
2096 ClassLoader scl = ClassLoader.initSystemClassLoader();
2097
2098 // set TCCL
2099 Thread.currentThread().setContextClassLoader(scl);
2100
2101 // system is fully initialized
2102 VM.initLevel(4);
2103 }
2104
2105 private static void setJavaLangAccess() {
2106 // Allow privileged classes outside of java.lang
2107 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2108 public List<Method> getDeclaredPublicMethods(Class<?> klass, String name, Class<?>... parameterTypes) {
2109 return klass.getDeclaredPublicMethods(name, parameterTypes);
2110 }
2111 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2112 return klass.getConstantPool();
2113 }
2114 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2115 return klass.casAnnotationType(oldType, newType);
2116 }
2117 public AnnotationType getAnnotationType(Class<?> klass) {
2118 return klass.getAnnotationType();
2119 }
2120 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2121 return klass.getDeclaredAnnotationMap();
2122 }
2123 public byte[] getRawClassAnnotations(Class<?> klass) {
2124 return klass.getRawAnnotations();
2125 }
2126 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2127 return klass.getRawTypeAnnotations();
2128 }
2129 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2130 return Class.getExecutableTypeAnnotationBytes(executable);
2131 }
2132 public <E extends Enum<E>>
2133 E[] getEnumConstantsShared(Class<E> klass) {
2134 return klass.getEnumConstantsShared();
2135 }
2136 public void blockedOn(Interruptible b) {
2137 Thread.blockedOn(b);
2138 }
2139 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2140 Shutdown.add(slot, registerShutdownInProgress, hook);
2141 }
2142 public Thread newThreadWithAcc(Runnable target, AccessControlContext acc) {
2143 return new Thread(target, acc);
2144 }
2145 @SuppressWarnings("deprecation")
2146 public void invokeFinalize(Object o) throws Throwable {
2147 o.finalize();
2148 }
2149 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2150 return cl.createOrGetClassLoaderValueMap();
2151 }
2152 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2153 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2154 }
2155 public Class<?> findBootstrapClassOrNull(ClassLoader cl, String name) {
2156 return cl.findBootstrapClassOrNull(name);
2157 }
2158 public Package definePackage(ClassLoader cl, String name, Module module) {
2159 return cl.definePackage(name, module);
2160 }
2161 public String fastUUID(long lsb, long msb) {
2162 return Long.fastUUID(lsb, msb);
2163 }
2164 public void addNonExportedPackages(ModuleLayer layer) {
2165 SecurityManager.addNonExportedPackages(layer);
2166 }
2167 public void invalidatePackageAccessCache() {
2168 SecurityManager.invalidatePackageAccessCache();
2169 }
2170 public Module defineModule(ClassLoader loader,
2171 ModuleDescriptor descriptor,
2172 URI uri) {
2173 return new Module(null, loader, descriptor, uri);
2174 }
2175 public Module defineUnnamedModule(ClassLoader loader) {
2176 return new Module(loader);
2177 }
2178 public void addReads(Module m1, Module m2) {
2179 m1.implAddReads(m2);
2180 }
2181 public void addReadsAllUnnamed(Module m) {
2182 m.implAddReadsAllUnnamed();
2183 }
2184 public void addExports(Module m, String pn, Module other) {
2185 m.implAddExports(pn, other);
2186 }
2187 public void addExportsToAllUnnamed(Module m, String pn) {
2188 m.implAddExportsToAllUnnamed(pn);
2189 }
2190 public void addOpens(Module m, String pn, Module other) {
2191 m.implAddOpens(pn, other);
2192 }
2193 public void addOpensToAllUnnamed(Module m, String pn) {
2194 m.implAddOpensToAllUnnamed(pn);
2195 }
2196 public void addOpensToAllUnnamed(Module m, Iterator<String> packages) {
2197 m.implAddOpensToAllUnnamed(packages);
2198 }
2199 public void addUses(Module m, Class<?> service) {
2200 m.implAddUses(service);
2201 }
2202 public boolean isReflectivelyExported(Module m, String pn, Module other) {
2203 return m.isReflectivelyExported(pn, other);
2204 }
2205 public boolean isReflectivelyOpened(Module m, String pn, Module other) {
2206 return m.isReflectivelyOpened(pn, other);
2207 }
2208 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2209 return layer.getServicesCatalog();
2210 }
2211 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2212 return layer.layers();
2213 }
2214 public Stream<ModuleLayer> layers(ClassLoader loader) {
2215 return ModuleLayer.layers(loader);
2216 }
2217
2218 public String newStringNoRepl(byte[] bytes, Charset cs) throws CharacterCodingException {
2219 return StringCoding.newStringNoRepl(bytes, cs);
2220 }
2221
2222 public byte[] getBytesNoRepl(String s, Charset cs) throws CharacterCodingException {
2223 return StringCoding.getBytesNoRepl(s, cs);
2224 }
2225
2226 public String newStringUTF8NoRepl(byte[] bytes, int off, int len) {
2227 return StringCoding.newStringUTF8NoRepl(bytes, off, len);
2228 }
2229
2230 public byte[] getBytesUTF8NoRepl(String s) {
2231 return StringCoding.getBytesUTF8NoRepl(s);
2232 }
2233
2234 });
2235 }
2236 }