1 /*
2 * Copyright (c) 1994, 2017, 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.net.URL;
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.util.Map;
52 import java.util.Objects;
53 import java.util.Properties;
54 import java.util.PropertyPermission;
55 import java.util.ResourceBundle;
56 import java.util.function.Supplier;
57 import java.util.concurrent.ConcurrentHashMap;
58 import java.util.stream.Stream;
59
60 import jdk.internal.module.ModuleBootstrap;
61 import jdk.internal.module.ServicesCatalog;
62 import jdk.internal.reflect.CallerSensitive;
63 import jdk.internal.reflect.Reflection;
64 import jdk.internal.HotSpotIntrinsicCandidate;
65 import jdk.internal.misc.JavaLangAccess;;
66 import jdk.internal.misc.SharedSecrets;;
67 import jdk.internal.misc.VM;
68 import jdk.internal.logger.LoggerFinderLoader;
69 import jdk.internal.logger.LazyLoggers;
70 import jdk.internal.logger.LocalizedLoggerWrapper;
71 import sun.reflect.annotation.AnnotationType;
72 import sun.nio.ch.Interruptible;
73 import sun.security.util.SecurityConstants;
74
75 /**
76 * The <code>System</code> class contains several useful class fields
77 * and methods. It cannot be instantiated.
78 *
79 * <p>Among the facilities provided by the <code>System</code> class
80 * are standard input, standard output, and error output streams;
81 * access to externally defined properties and environment
82 * variables; a means of loading files and libraries; and a utility
83 * method for quickly copying a portion of an array.
84 *
85 * @author unascribed
86 * @since 1.0
87 */
88 public final class System {
89 /* register the natives via the static initializer.
90 *
91 * VM will invoke the initializeSystemClass method to complete
92 * the initialization for this class separated from clinit.
93 * Note that to use properties set by the VM, see the constraints
94 * described in the initializeSystemClass method.
95 */
96 private static native void registerNatives();
97 static {
98 registerNatives();
99 }
100
101 /** Don't let anyone instantiate this class */
102 private System() {
103 }
104
105 /**
106 * The "standard" input stream. This stream is already
107 * open and ready to supply input data. Typically this stream
108 * corresponds to keyboard input or another input source specified by
109 * the host environment or user.
110 */
111 public static final InputStream in = null;
112
113 /**
114 * The "standard" output stream. This stream is already
115 * open and ready to accept output data. Typically this stream
116 * corresponds to display output or another output destination
117 * specified by the host environment or user.
118 * <p>
119 * For simple stand-alone Java applications, a typical way to write
120 * a line of output data is:
121 * <blockquote><pre>
122 * System.out.println(data)
123 * </pre></blockquote>
124 * <p>
125 * See the <code>println</code> methods in class <code>PrintStream</code>.
126 *
127 * @see java.io.PrintStream#println()
128 * @see java.io.PrintStream#println(boolean)
129 * @see java.io.PrintStream#println(char)
130 * @see java.io.PrintStream#println(char[])
131 * @see java.io.PrintStream#println(double)
132 * @see java.io.PrintStream#println(float)
133 * @see java.io.PrintStream#println(int)
134 * @see java.io.PrintStream#println(long)
135 * @see java.io.PrintStream#println(java.lang.Object)
136 * @see java.io.PrintStream#println(java.lang.String)
137 */
138 public static final PrintStream out = null;
139
140 /**
141 * The "standard" error output stream. This stream is already
142 * open and ready to accept output data.
143 * <p>
144 * Typically this stream corresponds to display output or another
145 * output destination specified by the host environment or user. By
146 * convention, this output stream is used to display error messages
147 * or other information that should come to the immediate attention
148 * of a user even if the principal output stream, the value of the
149 * variable <code>out</code>, has been redirected to a file or other
150 * destination that is typically not continuously monitored.
151 */
152 public static final PrintStream err = null;
153
154 /* The security manager for the system.
155 */
156 private static volatile SecurityManager security;
157
158 /**
159 * Reassigns the "standard" input stream.
160 *
161 * <p>First, if there is a security manager, its <code>checkPermission</code>
162 * method is called with a <code>RuntimePermission("setIO")</code> permission
163 * to see if it's ok to reassign the "standard" input stream.
164 *
165 * @param in the new standard input stream.
166 *
167 * @throws SecurityException
168 * if a security manager exists and its
169 * <code>checkPermission</code> method doesn't allow
170 * reassigning of the standard input stream.
171 *
172 * @see SecurityManager#checkPermission
173 * @see java.lang.RuntimePermission
174 *
175 * @since 1.1
176 */
177 public static void setIn(InputStream in) {
178 checkIO();
179 setIn0(in);
180 }
181
182 /**
183 * Reassigns the "standard" output stream.
184 *
185 * <p>First, if there is a security manager, its <code>checkPermission</code>
186 * method is called with a <code>RuntimePermission("setIO")</code> permission
187 * to see if it's ok to reassign the "standard" output stream.
188 *
189 * @param out the new standard output stream
190 *
191 * @throws SecurityException
192 * if a security manager exists and its
193 * <code>checkPermission</code> method doesn't allow
194 * reassigning of the standard output stream.
195 *
196 * @see SecurityManager#checkPermission
197 * @see java.lang.RuntimePermission
198 *
199 * @since 1.1
200 */
201 public static void setOut(PrintStream out) {
202 checkIO();
203 setOut0(out);
204 }
205
206 /**
207 * Reassigns the "standard" error output stream.
208 *
209 * <p>First, if there is a security manager, its <code>checkPermission</code>
210 * method is called with a <code>RuntimePermission("setIO")</code> permission
211 * to see if it's ok to reassign the "standard" error output stream.
212 *
213 * @param err the new standard error output stream.
214 *
215 * @throws SecurityException
216 * if a security manager exists and its
217 * <code>checkPermission</code> method doesn't allow
218 * reassigning of the standard error output stream.
219 *
220 * @see SecurityManager#checkPermission
221 * @see java.lang.RuntimePermission
222 *
223 * @since 1.1
224 */
225 public static void setErr(PrintStream err) {
226 checkIO();
227 setErr0(err);
228 }
229
230 private static volatile Console cons;
231 /**
232 * Returns the unique {@link java.io.Console Console} object associated
233 * with the current Java virtual machine, if any.
234 *
235 * @return The system console, if any, otherwise {@code null}.
236 *
237 * @since 1.6
238 */
239 public static Console console() {
240 Console c;
241 if ((c = cons) == null) {
242 synchronized (System.class) {
243 if ((c = cons) == null) {
244 cons = c = SharedSecrets.getJavaIOAccess().console();
245 }
246 }
247 }
248 return c;
249 }
250
251 /**
252 * Returns the channel inherited from the entity that created this
253 * Java virtual machine.
254 *
255 * <p> This method returns the channel obtained by invoking the
256 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
257 * inheritedChannel} method of the system-wide default
258 * {@link java.nio.channels.spi.SelectorProvider} object. </p>
259 *
260 * <p> In addition to the network-oriented channels described in
261 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
262 * inheritedChannel}, this method may return other kinds of
263 * channels in the future.
264 *
265 * @return The inherited channel, if any, otherwise {@code null}.
266 *
267 * @throws IOException
268 * If an I/O error occurs
269 *
270 * @throws SecurityException
271 * If a security manager is present and it does not
272 * permit access to the channel.
273 *
274 * @since 1.5
275 */
276 public static Channel inheritedChannel() throws IOException {
277 return SelectorProvider.provider().inheritedChannel();
278 }
279
280 private static void checkIO() {
281 SecurityManager sm = getSecurityManager();
282 if (sm != null) {
283 sm.checkPermission(new RuntimePermission("setIO"));
284 }
285 }
286
287 private static native void setIn0(InputStream in);
288 private static native void setOut0(PrintStream out);
289 private static native void setErr0(PrintStream err);
290
291 /**
292 * Sets the System security.
293 *
294 * <p> If there is a security manager already installed, this method first
295 * calls the security manager's <code>checkPermission</code> method
296 * with a <code>RuntimePermission("setSecurityManager")</code>
297 * permission to ensure it's ok to replace the existing
298 * security manager.
299 * This may result in throwing a <code>SecurityException</code>.
300 *
301 * <p> Otherwise, the argument is established as the current
302 * security manager. If the argument is <code>null</code> and no
303 * security manager has been established, then no action is taken and
304 * the method simply returns.
305 *
306 * @param s the security manager.
307 * @exception SecurityException if the security manager has already
308 * been set and its <code>checkPermission</code> method
309 * doesn't allow it to be replaced.
310 * @see #getSecurityManager
311 * @see SecurityManager#checkPermission
312 * @see java.lang.RuntimePermission
313 */
314 public static void setSecurityManager(final SecurityManager s) {
315 if (s != null) {
316 try {
317 s.checkPackageAccess("java.lang");
318 } catch (Exception e) {
319 // no-op
320 }
321 }
322 setSecurityManager0(s);
323 }
324
325 private static synchronized
326 void setSecurityManager0(final SecurityManager s) {
327 SecurityManager sm = getSecurityManager();
328 if (sm != null) {
329 // ask the currently installed security manager if we
330 // can replace it.
331 sm.checkPermission(new RuntimePermission
332 ("setSecurityManager"));
333 }
334
335 if ((s != null) && (s.getClass().getClassLoader() != null)) {
336 // New security manager class is not on bootstrap classpath.
337 // Cause policy to get initialized before we install the new
338 // security manager, in order to prevent infinite loops when
339 // trying to initialize the policy (which usually involves
340 // accessing some security and/or system properties, which in turn
341 // calls the installed security manager's checkPermission method
342 // which will loop infinitely if there is a non-system class
343 // (in this case: the new security manager class) on the stack).
344 AccessController.doPrivileged(new PrivilegedAction<>() {
345 public Object run() {
346 s.getClass().getProtectionDomain().implies
347 (SecurityConstants.ALL_PERMISSION);
348 return null;
349 }
350 });
351 }
352
353 security = s;
354 }
355
356 /**
357 * Gets the system security interface.
358 *
359 * @return if a security manager has already been established for the
360 * current application, then that security manager is returned;
361 * otherwise, <code>null</code> is returned.
362 * @see #setSecurityManager
363 */
364 public static SecurityManager getSecurityManager() {
365 return security;
366 }
367
368 /**
369 * Returns the current time in milliseconds. Note that
370 * while the unit of time of the return value is a millisecond,
371 * the granularity of the value depends on the underlying
372 * operating system and may be larger. For example, many
373 * operating systems measure time in units of tens of
374 * milliseconds.
375 *
376 * <p> See the description of the class <code>Date</code> for
377 * a discussion of slight discrepancies that may arise between
378 * "computer time" and coordinated universal time (UTC).
379 *
380 * @return the difference, measured in milliseconds, between
381 * the current time and midnight, January 1, 1970 UTC.
382 * @see java.util.Date
383 */
384 @HotSpotIntrinsicCandidate
385 public static native long currentTimeMillis();
386
387 /**
388 * Returns the current value of the running Java Virtual Machine's
389 * high-resolution time source, in nanoseconds.
390 *
391 * <p>This method can only be used to measure elapsed time and is
392 * not related to any other notion of system or wall-clock time.
393 * The value returned represents nanoseconds since some fixed but
394 * arbitrary <i>origin</i> time (perhaps in the future, so values
395 * may be negative). The same origin is used by all invocations of
396 * this method in an instance of a Java virtual machine; other
397 * virtual machine instances are likely to use a different origin.
398 *
399 * <p>This method provides nanosecond precision, but not necessarily
400 * nanosecond resolution (that is, how frequently the value changes)
401 * - no guarantees are made except that the resolution is at least as
402 * good as that of {@link #currentTimeMillis()}.
403 *
404 * <p>Differences in successive calls that span greater than
405 * approximately 292 years (2<sup>63</sup> nanoseconds) will not
406 * correctly compute elapsed time due to numerical overflow.
407 *
408 * <p>The values returned by this method become meaningful only when
409 * the difference between two such values, obtained within the same
410 * instance of a Java virtual machine, is computed.
411 *
412 * <p>For example, to measure how long some code takes to execute:
413 * <pre> {@code
414 * long startTime = System.nanoTime();
415 * // ... the code being measured ...
416 * long elapsedNanos = System.nanoTime() - startTime;}</pre>
417 *
418 * <p>To compare elapsed time against a timeout, use <pre> {@code
419 * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
420 * instead of <pre> {@code
421 * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
422 * because of the possibility of numerical overflow.
423 *
424 * @return the current value of the running Java Virtual Machine's
425 * high-resolution time source, in nanoseconds
426 * @since 1.5
427 */
428 @HotSpotIntrinsicCandidate
429 public static native long nanoTime();
430
431 /**
432 * Copies an array from the specified source array, beginning at the
433 * specified position, to the specified position of the destination array.
434 * A subsequence of array components are copied from the source
435 * array referenced by <code>src</code> to the destination array
436 * referenced by <code>dest</code>. The number of components copied is
437 * equal to the <code>length</code> argument. The components at
438 * positions <code>srcPos</code> through
439 * <code>srcPos+length-1</code> in the source array are copied into
440 * positions <code>destPos</code> through
441 * <code>destPos+length-1</code>, respectively, of the destination
442 * array.
443 * <p>
444 * If the <code>src</code> and <code>dest</code> arguments refer to the
445 * same array object, then the copying is performed as if the
446 * components at positions <code>srcPos</code> through
447 * <code>srcPos+length-1</code> were first copied to a temporary
448 * array with <code>length</code> components and then the contents of
449 * the temporary array were copied into positions
450 * <code>destPos</code> through <code>destPos+length-1</code> of the
451 * destination array.
452 * <p>
453 * If <code>dest</code> is <code>null</code>, then a
454 * <code>NullPointerException</code> is thrown.
455 * <p>
456 * If <code>src</code> is <code>null</code>, then a
457 * <code>NullPointerException</code> is thrown and the destination
458 * array is not modified.
459 * <p>
460 * Otherwise, if any of the following is true, an
461 * <code>ArrayStoreException</code> is thrown and the destination is
462 * not modified:
463 * <ul>
464 * <li>The <code>src</code> argument refers to an object that is not an
465 * array.
466 * <li>The <code>dest</code> argument refers to an object that is not an
467 * array.
468 * <li>The <code>src</code> argument and <code>dest</code> argument refer
469 * to arrays whose component types are different primitive types.
470 * <li>The <code>src</code> argument refers to an array with a primitive
471 * component type and the <code>dest</code> argument refers to an array
472 * with a reference component type.
473 * <li>The <code>src</code> argument refers to an array with a reference
474 * component type and the <code>dest</code> argument refers to an array
475 * with a primitive component type.
476 * </ul>
477 * <p>
478 * Otherwise, if any of the following is true, an
479 * <code>IndexOutOfBoundsException</code> is
480 * thrown and the destination is not modified:
481 * <ul>
482 * <li>The <code>srcPos</code> argument is negative.
483 * <li>The <code>destPos</code> argument is negative.
484 * <li>The <code>length</code> argument is negative.
485 * <li><code>srcPos+length</code> is greater than
486 * <code>src.length</code>, the length of the source array.
487 * <li><code>destPos+length</code> is greater than
488 * <code>dest.length</code>, the length of the destination array.
489 * </ul>
490 * <p>
491 * Otherwise, if any actual component of the source array from
492 * position <code>srcPos</code> through
493 * <code>srcPos+length-1</code> cannot be converted to the component
494 * type of the destination array by assignment conversion, an
495 * <code>ArrayStoreException</code> is thrown. In this case, let
496 * <b><i>k</i></b> be the smallest nonnegative integer less than
497 * length such that <code>src[srcPos+</code><i>k</i><code>]</code>
498 * cannot be converted to the component type of the destination
499 * array; when the exception is thrown, source array components from
500 * positions <code>srcPos</code> through
501 * <code>srcPos+</code><i>k</i><code>-1</code>
502 * will already have been copied to destination array positions
503 * <code>destPos</code> through
504 * <code>destPos+</code><i>k</I><code>-1</code> and no other
505 * positions of the destination array will have been modified.
506 * (Because of the restrictions already itemized, this
507 * paragraph effectively applies only to the situation where both
508 * arrays have component types that are reference types.)
509 *
510 * @param src the source array.
511 * @param srcPos starting position in the source array.
512 * @param dest the destination array.
513 * @param destPos starting position in the destination data.
514 * @param length the number of array elements to be copied.
515 * @exception IndexOutOfBoundsException if copying would cause
516 * access of data outside array bounds.
517 * @exception ArrayStoreException if an element in the <code>src</code>
518 * array could not be stored into the <code>dest</code> array
519 * because of a type mismatch.
520 * @exception NullPointerException if either <code>src</code> or
521 * <code>dest</code> is <code>null</code>.
522 */
523 @HotSpotIntrinsicCandidate
524 public static native void arraycopy(Object src, int srcPos,
525 Object dest, int destPos,
526 int length);
527
528 /**
529 * Returns the same hash code for the given object as
530 * would be returned by the default method hashCode(),
531 * whether or not the given object's class overrides
532 * hashCode().
533 * The hash code for the null reference is zero.
534 *
535 * @param x object for which the hashCode is to be calculated
536 * @return the hashCode
537 * @since 1.1
538 */
539 @HotSpotIntrinsicCandidate
540 public static native int identityHashCode(Object x);
541
542 /**
543 * System properties. The following properties are guaranteed to be defined:
544 * <dl>
545 * <dt>java.version <dd>Java version number
546 * <dt>java.vendor <dd>Java vendor specific string
547 * <dt>java.vendor.url <dd>Java vendor URL
548 * <dt>java.home <dd>Java installation directory
549 * <dt>java.class.version <dd>Java class version number
550 * <dt>java.class.path <dd>Java classpath
551 * <dt>os.name <dd>Operating System Name
552 * <dt>os.arch <dd>Operating System Architecture
553 * <dt>os.version <dd>Operating System Version
554 * <dt>file.separator <dd>File separator ("/" on Unix)
555 * <dt>path.separator <dd>Path separator (":" on Unix)
556 * <dt>line.separator <dd>Line separator ("\n" on Unix)
557 * <dt>user.name <dd>User account name
558 * <dt>user.home <dd>User home directory
559 * <dt>user.dir <dd>User's current working directory
560 * </dl>
561 */
562
563 private static Properties props;
564 private static native Properties initProperties(Properties props);
565
566 /**
567 * Determines the current system properties.
568 * <p>
569 * First, if there is a security manager, its
570 * <code>checkPropertiesAccess</code> method is called with no
571 * arguments. This may result in a security exception.
572 * <p>
573 * The current set of system properties for use by the
574 * {@link #getProperty(String)} method is returned as a
575 * <code>Properties</code> object. If there is no current set of
576 * system properties, a set of system properties is first created and
577 * initialized. This set of system properties always includes values
578 * for the following keys:
579 * <table class="striped">
580 * <caption style="display:none">Shows property keys and associated values</caption>
581 * <thead>
582 * <tr><th>Key</th>
583 * <th>Description of Associated Value</th></tr>
584 * </thead>
585 * <tbody>
586 * <tr><td><code>java.version</code></td>
587 * <td>Java Runtime Environment version which may be interpreted
588 * as a {@link Runtime.Version}</td></tr>
589 * <tr><td><code>java.vendor</code></td>
590 * <td>Java Runtime Environment vendor</td></tr>
591 * <tr><td><code>java.vendor.url</code></td>
592 * <td>Java vendor URL</td></tr>
593 * <tr><td><code>java.home</code></td>
594 * <td>Java installation directory</td></tr>
595 * <tr><td><code>java.vm.specification.version</code></td>
596 * <td>Java Virtual Machine specification version which may be
597 * interpreted as a {@link Runtime.Version}</td></tr>
598 * <tr><td><code>java.vm.specification.vendor</code></td>
599 * <td>Java Virtual Machine specification vendor</td></tr>
600 * <tr><td><code>java.vm.specification.name</code></td>
601 * <td>Java Virtual Machine specification name</td></tr>
602 * <tr><td><code>java.vm.version</code></td>
603 * <td>Java Virtual Machine implementation version which may be
604 * interpreted as a {@link Runtime.Version}</td></tr>
605 * <tr><td><code>java.vm.vendor</code></td>
606 * <td>Java Virtual Machine implementation vendor</td></tr>
607 * <tr><td><code>java.vm.name</code></td>
608 * <td>Java Virtual Machine implementation name</td></tr>
609 * <tr><td><code>java.specification.version</code></td>
610 * <td>Java Runtime Environment specification version which may be
611 * interpreted as a {@link Runtime.Version}</td></tr>
612 * <tr><td><code>java.specification.vendor</code></td>
613 * <td>Java Runtime Environment specification vendor</td></tr>
614 * <tr><td><code>java.specification.name</code></td>
615 * <td>Java Runtime Environment specification name</td></tr>
616 * <tr><td><code>java.class.version</code></td>
617 * <td>Java class format version number</td></tr>
618 * <tr><td><code>java.class.path</code></td>
619 * <td>Java class path</td></tr>
620 * <tr><td><code>java.library.path</code></td>
621 * <td>List of paths to search when loading libraries</td></tr>
622 * <tr><td><code>java.io.tmpdir</code></td>
623 * <td>Default temp file path</td></tr>
624 * <tr><td><code>java.compiler</code></td>
625 * <td>Name of JIT compiler to use</td></tr>
626 * <tr><td><code>os.name</code></td>
627 * <td>Operating system name</td></tr>
628 * <tr><td><code>os.arch</code></td>
629 * <td>Operating system architecture</td></tr>
630 * <tr><td><code>os.version</code></td>
631 * <td>Operating system version</td></tr>
632 * <tr><td><code>file.separator</code></td>
633 * <td>File separator ("/" on UNIX)</td></tr>
634 * <tr><td><code>path.separator</code></td>
635 * <td>Path separator (":" on UNIX)</td></tr>
636 * <tr><td><code>line.separator</code></td>
637 * <td>Line separator ("\n" on UNIX)</td></tr>
638 * <tr><td><code>user.name</code></td>
639 * <td>User's account name</td></tr>
640 * <tr><td><code>user.home</code></td>
641 * <td>User's home directory</td></tr>
642 * <tr><td><code>user.dir</code></td>
643 * <td>User's current working directory</td></tr>
644 * </tbody>
645 * </table>
646 * <p>
647 * Multiple paths in a system property value are separated by the path
648 * separator character of the platform.
649 * <p>
650 * Note that even if the security manager does not permit the
651 * <code>getProperties</code> operation, it may choose to permit the
652 * {@link #getProperty(String)} operation.
653 *
654 * @implNote In addition to the standard system properties, the system
655 * properties may include the following keys:
656 * <table class="striped">
657 * <caption style="display:none">Shows property keys and associated values</caption>
658 * <thead>
659 * <tr><th>Key</th>
660 * <th>Description of Associated Value</th></tr>
661 * </thead>
662 * <tbody>
663 * <tr><td>{@code jdk.module.path}</td>
664 * <td>The application module path</td></tr>
665 * <tr><td>{@code jdk.module.upgrade.path}</td>
666 * <td>The upgrade module path</td></tr>
667 * <tr><td>{@code jdk.module.main}</td>
668 * <td>The module name of the initial/main module</td></tr>
669 * <tr><td>{@code jdk.module.main.class}</td>
670 * <td>The main class name of the initial module</td></tr>
671 * </tbody>
672 * </table>
673 *
674 * @return the system properties
675 * @exception SecurityException if a security manager exists and its
676 * <code>checkPropertiesAccess</code> method doesn't allow access
677 * to the system properties.
678 * @see #setProperties
679 * @see java.lang.SecurityException
680 * @see java.lang.SecurityManager#checkPropertiesAccess()
681 * @see java.util.Properties
682 */
683 public static Properties getProperties() {
684 SecurityManager sm = getSecurityManager();
685 if (sm != null) {
686 sm.checkPropertiesAccess();
687 }
688
689 return props;
690 }
691
692 /**
693 * Returns the system-dependent line separator string. It always
694 * returns the same value - the initial value of the {@linkplain
695 * #getProperty(String) system property} {@code line.separator}.
696 *
697 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
698 * Windows systems it returns {@code "\r\n"}.
699 *
700 * @return the system-dependent line separator string
701 * @since 1.7
702 */
703 public static String lineSeparator() {
704 return lineSeparator;
705 }
706
707 private static String lineSeparator;
708
709 /**
710 * Sets the system properties to the <code>Properties</code>
711 * argument.
712 * <p>
713 * First, if there is a security manager, its
714 * <code>checkPropertiesAccess</code> method is called with no
715 * arguments. This may result in a security exception.
716 * <p>
717 * The argument becomes the current set of system properties for use
718 * by the {@link #getProperty(String)} method. If the argument is
719 * <code>null</code>, then the current set of system properties is
720 * forgotten.
721 *
722 * @param props the new system properties.
723 * @exception SecurityException if a security manager exists and its
724 * <code>checkPropertiesAccess</code> method doesn't allow access
725 * to the system properties.
726 * @see #getProperties
727 * @see java.util.Properties
728 * @see java.lang.SecurityException
729 * @see java.lang.SecurityManager#checkPropertiesAccess()
730 */
731 public static void setProperties(Properties props) {
732 SecurityManager sm = getSecurityManager();
733 if (sm != null) {
734 sm.checkPropertiesAccess();
735 }
736 if (props == null) {
737 props = new Properties();
738 initProperties(props);
739 }
740 System.props = props;
741 }
742
743 /**
744 * Gets the system property indicated by the specified key.
745 * <p>
746 * First, if there is a security manager, its
747 * <code>checkPropertyAccess</code> method is called with the key as
748 * its argument. This may result in a SecurityException.
749 * <p>
750 * If there is no current set of system properties, a set of system
751 * properties is first created and initialized in the same manner as
752 * for the <code>getProperties</code> method.
753 *
754 * @param key the name of the system property.
755 * @return the string value of the system property,
756 * or <code>null</code> if there is no property with that key.
757 *
758 * @exception SecurityException if a security manager exists and its
759 * <code>checkPropertyAccess</code> method doesn't allow
760 * access to the specified system property.
761 * @exception NullPointerException if <code>key</code> is
762 * <code>null</code>.
763 * @exception IllegalArgumentException if <code>key</code> is empty.
764 * @see #setProperty
765 * @see java.lang.SecurityException
766 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
767 * @see java.lang.System#getProperties()
768 */
769 public static String getProperty(String key) {
770 checkKey(key);
771 SecurityManager sm = getSecurityManager();
772 if (sm != null) {
773 sm.checkPropertyAccess(key);
774 }
775
776 return props.getProperty(key);
777 }
778
779 /**
780 * Gets the system property indicated by the specified key.
781 * <p>
782 * First, if there is a security manager, its
783 * <code>checkPropertyAccess</code> method is called with the
784 * <code>key</code> as its argument.
785 * <p>
786 * If there is no current set of system properties, a set of system
787 * properties is first created and initialized in the same manner as
788 * for the <code>getProperties</code> method.
789 *
790 * @param key the name of the system property.
791 * @param def a default value.
792 * @return the string value of the system property,
793 * or the default value if there is no property with that key.
794 *
795 * @exception SecurityException if a security manager exists and its
796 * <code>checkPropertyAccess</code> method doesn't allow
797 * access to the specified system property.
798 * @exception NullPointerException if <code>key</code> is
799 * <code>null</code>.
800 * @exception IllegalArgumentException if <code>key</code> is empty.
801 * @see #setProperty
802 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
803 * @see java.lang.System#getProperties()
804 */
805 public static String getProperty(String key, String def) {
806 checkKey(key);
807 SecurityManager sm = getSecurityManager();
808 if (sm != null) {
809 sm.checkPropertyAccess(key);
810 }
811
812 return props.getProperty(key, def);
813 }
814
815 /**
816 * Sets the system property indicated by the specified key.
817 * <p>
818 * First, if a security manager exists, its
819 * <code>SecurityManager.checkPermission</code> method
820 * is called with a <code>PropertyPermission(key, "write")</code>
821 * permission. This may result in a SecurityException being thrown.
822 * If no exception is thrown, the specified property is set to the given
823 * value.
824 *
825 * @param key the name of the system property.
826 * @param value the value of the system property.
827 * @return the previous value of the system property,
828 * or <code>null</code> if it did not have one.
829 *
830 * @exception SecurityException if a security manager exists and its
831 * <code>checkPermission</code> method doesn't allow
832 * setting of the specified property.
833 * @exception NullPointerException if <code>key</code> or
834 * <code>value</code> is <code>null</code>.
835 * @exception IllegalArgumentException if <code>key</code> is empty.
836 * @see #getProperty
837 * @see java.lang.System#getProperty(java.lang.String)
838 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
839 * @see java.util.PropertyPermission
840 * @see SecurityManager#checkPermission
841 * @since 1.2
842 */
843 public static String setProperty(String key, String value) {
844 checkKey(key);
845 SecurityManager sm = getSecurityManager();
846 if (sm != null) {
847 sm.checkPermission(new PropertyPermission(key,
848 SecurityConstants.PROPERTY_WRITE_ACTION));
849 }
850
851 return (String) props.setProperty(key, value);
852 }
853
854 /**
855 * Removes the system property indicated by the specified key.
856 * <p>
857 * First, if a security manager exists, its
858 * <code>SecurityManager.checkPermission</code> method
859 * is called with a <code>PropertyPermission(key, "write")</code>
860 * permission. This may result in a SecurityException being thrown.
861 * If no exception is thrown, the specified property is removed.
862 *
863 * @param key the name of the system property to be removed.
864 * @return the previous string value of the system property,
865 * or <code>null</code> if there was no property with that key.
866 *
867 * @exception SecurityException if a security manager exists and its
868 * <code>checkPropertyAccess</code> method doesn't allow
869 * access to the specified system property.
870 * @exception NullPointerException if <code>key</code> is
871 * <code>null</code>.
872 * @exception IllegalArgumentException if <code>key</code> is empty.
873 * @see #getProperty
874 * @see #setProperty
875 * @see java.util.Properties
876 * @see java.lang.SecurityException
877 * @see java.lang.SecurityManager#checkPropertiesAccess()
878 * @since 1.5
879 */
880 public static String clearProperty(String key) {
881 checkKey(key);
882 SecurityManager sm = getSecurityManager();
883 if (sm != null) {
884 sm.checkPermission(new PropertyPermission(key, "write"));
885 }
886
887 return (String) props.remove(key);
888 }
889
890 private static void checkKey(String key) {
891 if (key == null) {
892 throw new NullPointerException("key can't be null");
893 }
894 if (key.equals("")) {
895 throw new IllegalArgumentException("key can't be empty");
896 }
897 }
898
899 /**
900 * Gets the value of the specified environment variable. An
901 * environment variable is a system-dependent external named
902 * value.
903 *
904 * <p>If a security manager exists, its
905 * {@link SecurityManager#checkPermission checkPermission}
906 * method is called with a
907 * <code>{@link RuntimePermission}("getenv."+name)</code>
908 * permission. This may result in a {@link SecurityException}
909 * being thrown. If no exception is thrown the value of the
910 * variable <code>name</code> is returned.
911 *
912 * <p><a id="EnvironmentVSSystemProperties"><i>System
913 * properties</i> and <i>environment variables</i></a> are both
914 * conceptually mappings between names and values. Both
915 * mechanisms can be used to pass user-defined information to a
916 * Java process. Environment variables have a more global effect,
917 * because they are visible to all descendants of the process
918 * which defines them, not just the immediate Java subprocess.
919 * They can have subtly different semantics, such as case
920 * insensitivity, on different operating systems. For these
921 * reasons, environment variables are more likely to have
922 * unintended side effects. It is best to use system properties
923 * where possible. Environment variables should be used when a
924 * global effect is desired, or when an external system interface
925 * requires an environment variable (such as <code>PATH</code>).
926 *
927 * <p>On UNIX systems the alphabetic case of <code>name</code> is
928 * typically significant, while on Microsoft Windows systems it is
929 * typically not. For example, the expression
930 * <code>System.getenv("FOO").equals(System.getenv("foo"))</code>
931 * is likely to be true on Microsoft Windows.
932 *
933 * @param name the name of the environment variable
934 * @return the string value of the variable, or <code>null</code>
935 * if the variable is not defined in the system environment
936 * @throws NullPointerException if <code>name</code> is <code>null</code>
937 * @throws SecurityException
938 * if a security manager exists and its
939 * {@link SecurityManager#checkPermission checkPermission}
940 * method doesn't allow access to the environment variable
941 * <code>name</code>
942 * @see #getenv()
943 * @see ProcessBuilder#environment()
944 */
945 public static String getenv(String name) {
946 SecurityManager sm = getSecurityManager();
947 if (sm != null) {
948 sm.checkPermission(new RuntimePermission("getenv."+name));
949 }
950
951 return ProcessEnvironment.getenv(name);
952 }
953
954
955 /**
956 * Returns an unmodifiable string map view of the current system environment.
957 * The environment is a system-dependent mapping from names to
958 * values which is passed from parent to child processes.
959 *
960 * <p>If the system does not support environment variables, an
961 * empty map is returned.
962 *
963 * <p>The returned map will never contain null keys or values.
964 * Attempting to query the presence of a null key or value will
965 * throw a {@link NullPointerException}. Attempting to query
966 * the presence of a key or value which is not of type
967 * {@link String} will throw a {@link ClassCastException}.
968 *
969 * <p>The returned map and its collection views may not obey the
970 * general contract of the {@link Object#equals} and
971 * {@link Object#hashCode} methods.
972 *
973 * <p>The returned map is typically case-sensitive on all platforms.
974 *
975 * <p>If a security manager exists, its
976 * {@link SecurityManager#checkPermission checkPermission}
977 * method is called with a
978 * <code>{@link RuntimePermission}("getenv.*")</code>
979 * permission. This may result in a {@link SecurityException} being
980 * thrown.
981 *
982 * <p>When passing information to a Java subprocess,
983 * <a href=#EnvironmentVSSystemProperties>system properties</a>
984 * are generally preferred over environment variables.
985 *
986 * @return the environment as a map of variable names to values
987 * @throws SecurityException
988 * if a security manager exists and its
989 * {@link SecurityManager#checkPermission checkPermission}
990 * method doesn't allow access to the process environment
991 * @see #getenv(String)
992 * @see ProcessBuilder#environment()
993 * @since 1.5
994 */
995 public static java.util.Map<String,String> getenv() {
996 SecurityManager sm = getSecurityManager();
997 if (sm != null) {
998 sm.checkPermission(new RuntimePermission("getenv.*"));
999 }
1000
1001 return ProcessEnvironment.getenv();
1002 }
1003
1004 /**
1005 * {@code System.Logger} instances log messages that will be
1006 * routed to the underlying logging framework the {@link System.LoggerFinder
1007 * LoggerFinder} uses.
1008 * <p>
1009 * {@code System.Logger} instances are typically obtained from
1010 * the {@link java.lang.System System} class, by calling
1011 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
1012 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1013 * System.getLogger(loggerName, bundle)}.
1014 *
1015 * @see java.lang.System#getLogger(java.lang.String)
1016 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1017 * @see java.lang.System.LoggerFinder
1018 *
1019 * @since 9
1020 *
1021 */
1022 public interface Logger {
1023
1024 /**
1025 * System {@linkplain Logger loggers} levels.
1026 * <p>
1027 * A level has a {@linkplain #getName() name} and {@linkplain
1028 * #getSeverity() severity}.
1029 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
1030 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
1031 * by order of increasing severity.
1032 * <br>
1033 * {@link #ALL} and {@link #OFF}
1034 * are simple markers with severities mapped respectively to
1035 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
1036 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
1037 * <p>
1038 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
1039 * <p>
1040 * {@linkplain System.Logger.Level System logger levels} are mapped to
1041 * {@linkplain java.util.logging.Level java.util.logging levels}
1042 * of corresponding severity.
1043 * <br>The mapping is as follows:
1044 * <br><br>
1045 * <table border="1">
1046 * <caption>System.Logger Severity Level Mapping</caption>
1047 * <tr><td><b>System.Logger Levels</b></td>
1048 * <td>{@link Logger.Level#ALL ALL}</td>
1049 * <td>{@link Logger.Level#TRACE TRACE}</td>
1050 * <td>{@link Logger.Level#DEBUG DEBUG}</td>
1051 * <td>{@link Logger.Level#INFO INFO}</td>
1052 * <td>{@link Logger.Level#WARNING WARNING}</td>
1053 * <td>{@link Logger.Level#ERROR ERROR}</td>
1054 * <td>{@link Logger.Level#OFF OFF}</td>
1055 * </tr>
1056 * <tr><td><b>java.util.logging Levels</b></td>
1057 * <td>{@link java.util.logging.Level#ALL ALL}</td>
1058 * <td>{@link java.util.logging.Level#FINER FINER}</td>
1059 * <td>{@link java.util.logging.Level#FINE FINE}</td>
1060 * <td>{@link java.util.logging.Level#INFO INFO}</td>
1061 * <td>{@link java.util.logging.Level#WARNING WARNING}</td>
1062 * <td>{@link java.util.logging.Level#SEVERE SEVERE}</td>
1063 * <td>{@link java.util.logging.Level#OFF OFF}</td>
1064 * </tr>
1065 * </table>
1066 *
1067 * @since 9
1068 *
1069 * @see java.lang.System.LoggerFinder
1070 * @see java.lang.System.Logger
1071 */
1072 public enum Level {
1073
1074 // for convenience, we're reusing java.util.logging.Level int values
1075 // the mapping logic in sun.util.logging.PlatformLogger depends
1076 // on this.
1077 /**
1078 * A marker to indicate that all levels are enabled.
1079 * This level {@linkplain #getSeverity() severity} is
1080 * {@link Integer#MIN_VALUE}.
1081 */
1082 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
1083 /**
1084 * {@code TRACE} level: usually used to log diagnostic information.
1085 * This level {@linkplain #getSeverity() severity} is
1086 * {@code 400}.
1087 */
1088 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1089 /**
1090 * {@code DEBUG} level: usually used to log debug information traces.
1091 * This level {@linkplain #getSeverity() severity} is
1092 * {@code 500}.
1093 */
1094 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1095 /**
1096 * {@code INFO} level: usually used to log information messages.
1097 * This level {@linkplain #getSeverity() severity} is
1098 * {@code 800}.
1099 */
1100 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1101 /**
1102 * {@code WARNING} level: usually used to log warning messages.
1103 * This level {@linkplain #getSeverity() severity} is
1104 * {@code 900}.
1105 */
1106 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1107 /**
1108 * {@code ERROR} level: usually used to log error messages.
1109 * This level {@linkplain #getSeverity() severity} is
1110 * {@code 1000}.
1111 */
1112 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1113 /**
1114 * A marker to indicate that all levels are disabled.
1115 * This level {@linkplain #getSeverity() severity} is
1116 * {@link Integer#MAX_VALUE}.
1117 */
1118 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1119
1120 private final int severity;
1121
1122 private Level(int severity) {
1123 this.severity = severity;
1124 }
1125
1126 /**
1127 * Returns the name of this level.
1128 * @return this level {@linkplain #name()}.
1129 */
1130 public final String getName() {
1131 return name();
1132 }
1133
1134 /**
1135 * Returns the severity of this level.
1136 * A higher severity means a more severe condition.
1137 * @return this level severity.
1138 */
1139 public final int getSeverity() {
1140 return severity;
1141 }
1142 }
1143
1144 /**
1145 * Returns the name of this logger.
1146 *
1147 * @return the logger name.
1148 */
1149 public String getName();
1150
1151 /**
1152 * Checks if a message of the given level would be logged by
1153 * this logger.
1154 *
1155 * @param level the log message level.
1156 * @return {@code true} if the given log message level is currently
1157 * being logged.
1158 *
1159 * @throws NullPointerException if {@code level} is {@code null}.
1160 */
1161 public boolean isLoggable(Level level);
1162
1163 /**
1164 * Logs a message.
1165 *
1166 * @implSpec The default implementation for this method calls
1167 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1168 *
1169 * @param level the log message level.
1170 * @param msg the string message (or a key in the message catalog, if
1171 * this logger is a {@link
1172 * LoggerFinder#getLocalizedLogger(java.lang.String,
1173 * java.util.ResourceBundle, java.lang.Module) localized logger});
1174 * can be {@code null}.
1175 *
1176 * @throws NullPointerException if {@code level} is {@code null}.
1177 */
1178 public default void log(Level level, String msg) {
1179 log(level, (ResourceBundle) null, msg, (Object[]) null);
1180 }
1181
1182 /**
1183 * Logs a lazily supplied message.
1184 * <p>
1185 * If the logger is currently enabled for the given log message level
1186 * then a message is logged that is the result produced by the
1187 * given supplier function. Otherwise, the supplier is not operated on.
1188 *
1189 * @implSpec When logging is enabled for the given level, the default
1190 * implementation for this method calls
1191 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1192 *
1193 * @param level the log message level.
1194 * @param msgSupplier a supplier function that produces a message.
1195 *
1196 * @throws NullPointerException if {@code level} is {@code null},
1197 * or {@code msgSupplier} is {@code null}.
1198 */
1199 public default void log(Level level, Supplier<String> msgSupplier) {
1200 Objects.requireNonNull(msgSupplier);
1201 if (isLoggable(Objects.requireNonNull(level))) {
1202 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1203 }
1204 }
1205
1206 /**
1207 * Logs a message produced from the given object.
1208 * <p>
1209 * If the logger is currently enabled for the given log message level then
1210 * a message is logged that, by default, is the result produced from
1211 * calling toString on the given object.
1212 * Otherwise, the object is not operated on.
1213 *
1214 * @implSpec When logging is enabled for the given level, the default
1215 * implementation for this method calls
1216 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1217 *
1218 * @param level the log message level.
1219 * @param obj the object to log.
1220 *
1221 * @throws NullPointerException if {@code level} is {@code null}, or
1222 * {@code obj} is {@code null}.
1223 */
1224 public default void log(Level level, Object obj) {
1225 Objects.requireNonNull(obj);
1226 if (isLoggable(Objects.requireNonNull(level))) {
1227 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1228 }
1229 }
1230
1231 /**
1232 * Logs a message associated with a given throwable.
1233 *
1234 * @implSpec The default implementation for this method calls
1235 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1236 *
1237 * @param level the log message level.
1238 * @param msg the string message (or a key in the message catalog, if
1239 * this logger is a {@link
1240 * LoggerFinder#getLocalizedLogger(java.lang.String,
1241 * java.util.ResourceBundle, java.lang.Module) localized logger});
1242 * can be {@code null}.
1243 * @param thrown a {@code Throwable} associated with the log message;
1244 * can be {@code null}.
1245 *
1246 * @throws NullPointerException if {@code level} is {@code null}.
1247 */
1248 public default void log(Level level, String msg, Throwable thrown) {
1249 this.log(level, null, msg, thrown);
1250 }
1251
1252 /**
1253 * Logs a lazily supplied message associated with a given throwable.
1254 * <p>
1255 * If the logger is currently enabled for the given log message level
1256 * then a message is logged that is the result produced by the
1257 * given supplier function. Otherwise, the supplier is not operated on.
1258 *
1259 * @implSpec When logging is enabled for the given level, the default
1260 * implementation for this method calls
1261 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1262 *
1263 * @param level one of the log message level identifiers.
1264 * @param msgSupplier a supplier function that produces a message.
1265 * @param thrown a {@code Throwable} associated with log message;
1266 * can be {@code null}.
1267 *
1268 * @throws NullPointerException if {@code level} is {@code null}, or
1269 * {@code msgSupplier} is {@code null}.
1270 */
1271 public default void log(Level level, Supplier<String> msgSupplier,
1272 Throwable thrown) {
1273 Objects.requireNonNull(msgSupplier);
1274 if (isLoggable(Objects.requireNonNull(level))) {
1275 this.log(level, null, msgSupplier.get(), thrown);
1276 }
1277 }
1278
1279 /**
1280 * Logs a message with an optional list of parameters.
1281 *
1282 * @implSpec The default implementation for this method calls
1283 * {@code this.log(level, (ResourceBundle)null, format, params);}
1284 *
1285 * @param level one of the log message level identifiers.
1286 * @param format the string message format in {@link
1287 * java.text.MessageFormat} format, (or a key in the message
1288 * catalog, if this logger is a {@link
1289 * LoggerFinder#getLocalizedLogger(java.lang.String,
1290 * java.util.ResourceBundle, java.lang.Module) localized logger});
1291 * can be {@code null}.
1292 * @param params an optional list of parameters to the message (may be
1293 * none).
1294 *
1295 * @throws NullPointerException if {@code level} is {@code null}.
1296 */
1297 public default void log(Level level, String format, Object... params) {
1298 this.log(level, null, format, params);
1299 }
1300
1301 /**
1302 * Logs a localized message associated with a given throwable.
1303 * <p>
1304 * If the given resource bundle is non-{@code null}, the {@code msg}
1305 * string is localized using the given resource bundle.
1306 * Otherwise the {@code msg} string is not localized.
1307 *
1308 * @param level the log message level.
1309 * @param bundle a resource bundle to localize {@code msg}; can be
1310 * {@code null}.
1311 * @param msg the string message (or a key in the message catalog,
1312 * if {@code bundle} is not {@code null}); can be {@code null}.
1313 * @param thrown a {@code Throwable} associated with the log message;
1314 * can be {@code null}.
1315 *
1316 * @throws NullPointerException if {@code level} is {@code null}.
1317 */
1318 public void log(Level level, ResourceBundle bundle, String msg,
1319 Throwable thrown);
1320
1321 /**
1322 * Logs a message with resource bundle and an optional list of
1323 * parameters.
1324 * <p>
1325 * If the given resource bundle is non-{@code null}, the {@code format}
1326 * string is localized using the given resource bundle.
1327 * Otherwise the {@code format} string is not localized.
1328 *
1329 * @param level the log message level.
1330 * @param bundle a resource bundle to localize {@code format}; can be
1331 * {@code null}.
1332 * @param format the string message format in {@link
1333 * java.text.MessageFormat} format, (or a key in the message
1334 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1335 * @param params an optional list of parameters to the message (may be
1336 * none).
1337 *
1338 * @throws NullPointerException if {@code level} is {@code null}.
1339 */
1340 public void log(Level level, ResourceBundle bundle, String format,
1341 Object... params);
1342
1343
1344 }
1345
1346 /**
1347 * The {@code LoggerFinder} service is responsible for creating, managing,
1348 * and configuring loggers to the underlying framework it uses.
1349 * <p>
1350 * A logger finder is a concrete implementation of this class that has a
1351 * zero-argument constructor and implements the abstract methods defined
1352 * by this class.
1353 * The loggers returned from a logger finder are capable of routing log
1354 * messages to the logging backend this provider supports.
1355 * A given invocation of the Java Runtime maintains a single
1356 * system-wide LoggerFinder instance that is loaded as follows:
1357 * <ul>
1358 * <li>First it finds any custom {@code LoggerFinder} provider
1359 * using the {@link java.util.ServiceLoader} facility with the
1360 * {@linkplain ClassLoader#getSystemClassLoader() system class
1361 * loader}.</li>
1362 * <li>If no {@code LoggerFinder} provider is found, the system default
1363 * {@code LoggerFinder} implementation will be used.</li>
1364 * </ul>
1365 * <p>
1366 * An application can replace the logging backend
1367 * <i>even when the java.logging module is present</i>, by simply providing
1368 * and declaring an implementation of the {@link LoggerFinder} service.
1369 * <p>
1370 * <b>Default Implementation</b>
1371 * <p>
1372 * The system default {@code LoggerFinder} implementation uses
1373 * {@code java.util.logging} as the backend framework when the
1374 * {@code java.logging} module is present.
1375 * It returns a {@linkplain System.Logger logger} instance
1376 * that will route log messages to a {@link java.util.logging.Logger
1377 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1378 * present, the default implementation will return a simple logger
1379 * instance that will route log messages of {@code INFO} level and above to
1380 * the console ({@code System.err}).
1381 * <p>
1382 * <b>Logging Configuration</b>
1383 * <p>
1384 * {@linkplain Logger Logger} instances obtained from the
1385 * {@code LoggerFinder} factory methods are not directly configurable by
1386 * the application. Configuration is the responsibility of the underlying
1387 * logging backend, and usually requires using APIs specific to that backend.
1388 * <p>For the default {@code LoggerFinder} implementation
1389 * using {@code java.util.logging} as its backend, refer to
1390 * {@link java.util.logging java.util.logging} for logging configuration.
1391 * For the default {@code LoggerFinder} implementation returning simple loggers
1392 * when the {@code java.logging} module is absent, the configuration
1393 * is implementation dependent.
1394 * <p>
1395 * Usually an application that uses a logging framework will log messages
1396 * through a logger facade defined (or supported) by that framework.
1397 * Applications that wish to use an external framework should log
1398 * through the facade associated with that framework.
1399 * <p>
1400 * A system class that needs to log messages will typically obtain
1401 * a {@link System.Logger} instance to route messages to the logging
1402 * framework selected by the application.
1403 * <p>
1404 * Libraries and classes that only need loggers to produce log messages
1405 * should not attempt to configure loggers by themselves, as that
1406 * would make them dependent from a specific implementation of the
1407 * {@code LoggerFinder} service.
1408 * <p>
1409 * In addition, when a security manager is present, loggers provided to
1410 * system classes should not be directly configurable through the logging
1411 * backend without requiring permissions.
1412 * <br>
1413 * It is the responsibility of the provider of
1414 * the concrete {@code LoggerFinder} implementation to ensure that
1415 * these loggers are not configured by untrusted code without proper
1416 * permission checks, as configuration performed on such loggers usually
1417 * affects all applications in the same Java Runtime.
1418 * <p>
1419 * <b>Message Levels and Mapping to backend levels</b>
1420 * <p>
1421 * A logger finder is responsible for mapping from a {@code
1422 * System.Logger.Level} to a level supported by the logging backend it uses.
1423 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1424 * maps {@code System.Logger} levels to
1425 * {@linkplain java.util.logging.Level java.util.logging} levels
1426 * of corresponding severity - as described in {@link Logger.Level
1427 * Logger.Level}.
1428 *
1429 * @see java.lang.System
1430 * @see java.lang.System.Logger
1431 *
1432 * @since 9
1433 */
1434 public static abstract class LoggerFinder {
1435 /**
1436 * The {@code RuntimePermission("loggerFinder")} is
1437 * necessary to subclass and instantiate the {@code LoggerFinder} class,
1438 * as well as to obtain loggers from an instance of that class.
1439 */
1440 static final RuntimePermission LOGGERFINDER_PERMISSION =
1441 new RuntimePermission("loggerFinder");
1442
1443 /**
1444 * Creates a new instance of {@code LoggerFinder}.
1445 *
1446 * @implNote It is recommended that a {@code LoggerFinder} service
1447 * implementation does not perform any heavy initialization in its
1448 * constructor, in order to avoid possible risks of deadlock or class
1449 * loading cycles during the instantiation of the service provider.
1450 *
1451 * @throws SecurityException if a security manager is present and its
1452 * {@code checkPermission} method doesn't allow the
1453 * {@code RuntimePermission("loggerFinder")}.
1454 */
1455 protected LoggerFinder() {
1456 this(checkPermission());
1457 }
1458
1459 private LoggerFinder(Void unused) {
1460 // nothing to do.
1461 }
1462
1463 private static Void checkPermission() {
1464 final SecurityManager sm = System.getSecurityManager();
1465 if (sm != null) {
1466 sm.checkPermission(LOGGERFINDER_PERMISSION);
1467 }
1468 return null;
1469 }
1470
1471 /**
1472 * Returns an instance of {@link Logger Logger}
1473 * for the given {@code module}.
1474 *
1475 * @param name the name of the logger.
1476 * @param module the module for which the logger is being requested.
1477 *
1478 * @return a {@link Logger logger} suitable for use within the given
1479 * module.
1480 * @throws NullPointerException if {@code name} is {@code null} or
1481 * {@code module} is {@code null}.
1482 * @throws SecurityException if a security manager is present and its
1483 * {@code checkPermission} method doesn't allow the
1484 * {@code RuntimePermission("loggerFinder")}.
1485 */
1486 public abstract Logger getLogger(String name, Module module);
1487
1488 /**
1489 * Returns a localizable instance of {@link Logger Logger}
1490 * for the given {@code module}.
1491 * The returned logger will use the provided resource bundle for
1492 * message localization.
1493 *
1494 * @implSpec By default, this method calls {@link
1495 * #getLogger(java.lang.String, java.lang.Module)
1496 * this.getLogger(name, module)} to obtain a logger, then wraps that
1497 * logger in a {@link Logger} instance where all methods that do not
1498 * take a {@link ResourceBundle} as parameter are redirected to one
1499 * which does - passing the given {@code bundle} for
1500 * localization. So for instance, a call to {@link
1501 * Logger#log(Level, String) Logger.log(Level.INFO, msg)}
1502 * will end up as a call to {@link
1503 * Logger#log(Level, ResourceBundle, String, Object...)
1504 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1505 * logger instance.
1506 * Note however that by default, string messages returned by {@link
1507 * java.util.function.Supplier Supplier<String>} will not be
1508 * localized, as it is assumed that such strings are messages which are
1509 * already constructed, rather than keys in a resource bundle.
1510 * <p>
1511 * An implementation of {@code LoggerFinder} may override this method,
1512 * for example, when the underlying logging backend provides its own
1513 * mechanism for localizing log messages, then such a
1514 * {@code LoggerFinder} would be free to return a logger
1515 * that makes direct use of the mechanism provided by the backend.
1516 *
1517 * @param name the name of the logger.
1518 * @param bundle a resource bundle; can be {@code null}.
1519 * @param module the module for which the logger is being requested.
1520 * @return an instance of {@link Logger Logger} which will use the
1521 * provided resource bundle for message localization.
1522 *
1523 * @throws NullPointerException if {@code name} is {@code null} or
1524 * {@code module} is {@code null}.
1525 * @throws SecurityException if a security manager is present and its
1526 * {@code checkPermission} method doesn't allow the
1527 * {@code RuntimePermission("loggerFinder")}.
1528 */
1529 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1530 Module module) {
1531 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1532 }
1533
1534 /**
1535 * Returns the {@code LoggerFinder} instance. There is one
1536 * single system-wide {@code LoggerFinder} instance in
1537 * the Java Runtime. See the class specification of how the
1538 * {@link LoggerFinder LoggerFinder} implementation is located and
1539 * loaded.
1540
1541 * @return the {@link LoggerFinder LoggerFinder} instance.
1542 * @throws SecurityException if a security manager is present and its
1543 * {@code checkPermission} method doesn't allow the
1544 * {@code RuntimePermission("loggerFinder")}.
1545 */
1546 public static LoggerFinder getLoggerFinder() {
1547 final SecurityManager sm = System.getSecurityManager();
1548 if (sm != null) {
1549 sm.checkPermission(LOGGERFINDER_PERMISSION);
1550 }
1551 return accessProvider();
1552 }
1553
1554
1555 private static volatile LoggerFinder service;
1556 static LoggerFinder accessProvider() {
1557 // We do not need to synchronize: LoggerFinderLoader will
1558 // always return the same instance, so if we don't have it,
1559 // just fetch it again.
1560 if (service == null) {
1561 PrivilegedAction<LoggerFinder> pa =
1562 () -> LoggerFinderLoader.getLoggerFinder();
1563 service = AccessController.doPrivileged(pa, null,
1564 LOGGERFINDER_PERMISSION);
1565 }
1566 return service;
1567 }
1568
1569 }
1570
1571
1572 /**
1573 * Returns an instance of {@link Logger Logger} for the caller's
1574 * use.
1575 *
1576 * @implSpec
1577 * Instances returned by this method route messages to loggers
1578 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1579 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1580 * {@code module} is the caller's module.
1581 * In cases where {@code System.getLogger} is called from a context where
1582 * there is no caller frame on the stack (e.g when called directly
1583 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1584 * To obtain a logger in such a context, use an auxiliary class that will
1585 * implicitly be identified as the caller, or use the system {@link
1586 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1587 * Note that doing the latter may eagerly initialize the underlying
1588 * logging system.
1589 *
1590 * @apiNote
1591 * This method may defer calling the {@link
1592 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1593 * LoggerFinder.getLogger} method to create an actual logger supplied by
1594 * the logging backend, for instance, to allow loggers to be obtained during
1595 * the system initialization time.
1596 *
1597 * @param name the name of the logger.
1598 * @return an instance of {@link Logger} that can be used by the calling
1599 * class.
1600 * @throws NullPointerException if {@code name} is {@code null}.
1601 * @throws IllegalCallerException if there is no Java caller frame on the
1602 * stack.
1603 *
1604 * @since 9
1605 */
1606 @CallerSensitive
1607 public static Logger getLogger(String name) {
1608 Objects.requireNonNull(name);
1609 final Class<?> caller = Reflection.getCallerClass();
1610 if (caller == null) {
1611 throw new IllegalCallerException("no caller frame");
1612 }
1613 return LazyLoggers.getLogger(name, caller.getModule());
1614 }
1615
1616 /**
1617 * Returns a localizable instance of {@link Logger
1618 * Logger} for the caller's use.
1619 * The returned logger will use the provided resource bundle for message
1620 * localization.
1621 *
1622 * @implSpec
1623 * The returned logger will perform message localization as specified
1624 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1625 * java.util.ResourceBundle, java.lang.Module)
1626 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1627 * {@code module} is the caller's module.
1628 * In cases where {@code System.getLogger} is called from a context where
1629 * there is no caller frame on the stack (e.g when called directly
1630 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1631 * To obtain a logger in such a context, use an auxiliary class that
1632 * will implicitly be identified as the caller, or use the system {@link
1633 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1634 * Note that doing the latter may eagerly initialize the underlying
1635 * logging system.
1636 *
1637 * @apiNote
1638 * This method is intended to be used after the system is fully initialized.
1639 * This method may trigger the immediate loading and initialization
1640 * of the {@link LoggerFinder} service, which may cause issues if the
1641 * Java Runtime is not ready to initialize the concrete service
1642 * implementation yet.
1643 * System classes which may be loaded early in the boot sequence and
1644 * need to log localized messages should create a logger using
1645 * {@link #getLogger(java.lang.String)} and then use the log methods that
1646 * take a resource bundle as parameter.
1647 *
1648 * @param name the name of the logger.
1649 * @param bundle a resource bundle.
1650 * @return an instance of {@link Logger} which will use the provided
1651 * resource bundle for message localization.
1652 * @throws NullPointerException if {@code name} is {@code null} or
1653 * {@code bundle} is {@code null}.
1654 * @throws IllegalCallerException if there is no Java caller frame on the
1655 * stack.
1656 *
1657 * @since 9
1658 */
1659 @CallerSensitive
1660 public static Logger getLogger(String name, ResourceBundle bundle) {
1661 final ResourceBundle rb = Objects.requireNonNull(bundle);
1662 Objects.requireNonNull(name);
1663 final Class<?> caller = Reflection.getCallerClass();
1664 if (caller == null) {
1665 throw new IllegalCallerException("no caller frame");
1666 }
1667 final SecurityManager sm = System.getSecurityManager();
1668 // We don't use LazyLoggers if a resource bundle is specified.
1669 // Bootstrap sensitive classes in the JDK do not use resource bundles
1670 // when logging. This could be revisited later, if it needs to.
1671 if (sm != null) {
1672 final PrivilegedAction<Logger> pa =
1673 () -> LoggerFinder.accessProvider()
1674 .getLocalizedLogger(name, rb, caller.getModule());
1675 return AccessController.doPrivileged(pa, null,
1676 LoggerFinder.LOGGERFINDER_PERMISSION);
1677 }
1678 return LoggerFinder.accessProvider()
1679 .getLocalizedLogger(name, rb, caller.getModule());
1680 }
1681
1682 /**
1683 * Terminates the currently running Java Virtual Machine. The
1684 * argument serves as a status code; by convention, a nonzero status
1685 * code indicates abnormal termination.
1686 * <p>
1687 * This method calls the <code>exit</code> method in class
1688 * <code>Runtime</code>. This method never returns normally.
1689 * <p>
1690 * The call <code>System.exit(n)</code> is effectively equivalent to
1691 * the call:
1692 * <blockquote><pre>
1693 * Runtime.getRuntime().exit(n)
1694 * </pre></blockquote>
1695 *
1696 * @param status exit status.
1697 * @throws SecurityException
1698 * if a security manager exists and its <code>checkExit</code>
1699 * method doesn't allow exit with the specified status.
1700 * @see java.lang.Runtime#exit(int)
1701 */
1702 public static void exit(int status) {
1703 Runtime.getRuntime().exit(status);
1704 }
1705
1706 /**
1707 * Runs the garbage collector.
1708 * <p>
1709 * Calling the <code>gc</code> method suggests that the Java Virtual
1710 * Machine expend effort toward recycling unused objects in order to
1711 * make the memory they currently occupy available for quick reuse.
1712 * When control returns from the method call, the Java Virtual
1713 * Machine has made a best effort to reclaim space from all discarded
1714 * objects.
1715 * <p>
1716 * The call <code>System.gc()</code> is effectively equivalent to the
1717 * call:
1718 * <blockquote><pre>
1719 * Runtime.getRuntime().gc()
1720 * </pre></blockquote>
1721 *
1722 * @see java.lang.Runtime#gc()
1723 */
1724 public static void gc() {
1725 Runtime.getRuntime().gc();
1726 }
1727
1728 /**
1729 * Runs the finalization methods of any objects pending finalization.
1730 * <p>
1731 * Calling this method suggests that the Java Virtual Machine expend
1732 * effort toward running the <code>finalize</code> methods of objects
1733 * that have been found to be discarded but whose <code>finalize</code>
1734 * methods have not yet been run. When control returns from the
1735 * method call, the Java Virtual Machine has made a best effort to
1736 * complete all outstanding finalizations.
1737 * <p>
1738 * The call <code>System.runFinalization()</code> is effectively
1739 * equivalent to the call:
1740 * <blockquote><pre>
1741 * Runtime.getRuntime().runFinalization()
1742 * </pre></blockquote>
1743 *
1744 * @see java.lang.Runtime#runFinalization()
1745 */
1746 public static void runFinalization() {
1747 Runtime.getRuntime().runFinalization();
1748 }
1749
1750 /**
1751 * Enable or disable finalization on exit; doing so specifies that the
1752 * finalizers of all objects that have finalizers that have not yet been
1753 * automatically invoked are to be run before the Java runtime exits.
1754 * By default, finalization on exit is disabled.
1755 *
1756 * <p>If there is a security manager,
1757 * its <code>checkExit</code> method is first called
1758 * with 0 as its argument to ensure the exit is allowed.
1759 * This could result in a SecurityException.
1760 *
1761 * @deprecated This method is inherently unsafe. It may result in
1762 * finalizers being called on live objects while other threads are
1763 * concurrently manipulating those objects, resulting in erratic
1764 * behavior or deadlock.
1765 * This method is subject to removal in a future version of Java SE.
1766 * @param value indicating enabling or disabling of finalization
1767 * @throws SecurityException
1768 * if a security manager exists and its <code>checkExit</code>
1769 * method doesn't allow the exit.
1770 *
1771 * @see java.lang.Runtime#exit(int)
1772 * @see java.lang.Runtime#gc()
1773 * @see java.lang.SecurityManager#checkExit(int)
1774 * @since 1.1
1775 */
1776 @Deprecated(since="1.2", forRemoval=true)
1777 @SuppressWarnings("removal")
1778 public static void runFinalizersOnExit(boolean value) {
1779 Runtime.runFinalizersOnExit(value);
1780 }
1781
1782 /**
1783 * Loads the native library specified by the filename argument. The filename
1784 * argument must be an absolute path name.
1785 *
1786 * If the filename argument, when stripped of any platform-specific library
1787 * prefix, path, and file extension, indicates a library whose name is,
1788 * for example, L, and a native library called L is statically linked
1789 * with the VM, then the JNI_OnLoad_L function exported by the library
1790 * is invoked rather than attempting to load a dynamic library.
1791 * A filename matching the argument does not have to exist in the
1792 * file system.
1793 * See the JNI Specification for more details.
1794 *
1795 * Otherwise, the filename argument is mapped to a native library image in
1796 * an implementation-dependent manner.
1797 *
1798 * <p>
1799 * The call <code>System.load(name)</code> is effectively equivalent
1800 * to the call:
1801 * <blockquote><pre>
1802 * Runtime.getRuntime().load(name)
1803 * </pre></blockquote>
1804 *
1805 * @param filename the file to load.
1806 * @exception SecurityException if a security manager exists and its
1807 * <code>checkLink</code> method doesn't allow
1808 * loading of the specified dynamic library
1809 * @exception UnsatisfiedLinkError if either the filename is not an
1810 * absolute path name, the native library is not statically
1811 * linked with the VM, or the library cannot be mapped to
1812 * a native library image by the host system.
1813 * @exception NullPointerException if <code>filename</code> is
1814 * <code>null</code>
1815 * @see java.lang.Runtime#load(java.lang.String)
1816 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1817 */
1818 @CallerSensitive
1819 public static void load(String filename) {
1820 Runtime.getRuntime().load0(Reflection.getCallerClass(), filename);
1821 }
1822
1823 /**
1824 * Loads the native library specified by the <code>libname</code>
1825 * argument. The <code>libname</code> argument must not contain any platform
1826 * specific prefix, file extension or path. If a native library
1827 * called <code>libname</code> is statically linked with the VM, then the
1828 * JNI_OnLoad_<code>libname</code> function exported by the library is invoked.
1829 * See the JNI Specification for more details.
1830 *
1831 * Otherwise, the libname argument is loaded from a system library
1832 * location and mapped to a native library image in an implementation-
1833 * dependent manner.
1834 * <p>
1835 * The call <code>System.loadLibrary(name)</code> is effectively
1836 * equivalent to the call
1837 * <blockquote><pre>
1838 * Runtime.getRuntime().loadLibrary(name)
1839 * </pre></blockquote>
1840 *
1841 * @param libname the name of the library.
1842 * @exception SecurityException if a security manager exists and its
1843 * <code>checkLink</code> method doesn't allow
1844 * loading of the specified dynamic library
1845 * @exception UnsatisfiedLinkError if either the libname argument
1846 * contains a file path, the native library is not statically
1847 * linked with the VM, or the library cannot be mapped to a
1848 * native library image by the host system.
1849 * @exception NullPointerException if <code>libname</code> is
1850 * <code>null</code>
1851 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1852 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1853 */
1854 @CallerSensitive
1855 public static void loadLibrary(String libname) {
1856 Runtime.getRuntime().loadLibrary0(Reflection.getCallerClass(), libname);
1857 }
1858
1859 /**
1860 * Maps a library name into a platform-specific string representing
1861 * a native library.
1862 *
1863 * @param libname the name of the library.
1864 * @return a platform-dependent native library name.
1865 * @exception NullPointerException if <code>libname</code> is
1866 * <code>null</code>
1867 * @see java.lang.System#loadLibrary(java.lang.String)
1868 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1869 * @since 1.2
1870 */
1871 public static native String mapLibraryName(String libname);
1872
1873 /**
1874 * Create PrintStream for stdout/err based on encoding.
1875 */
1876 private static PrintStream newPrintStream(FileOutputStream fos, String enc) {
1877 if (enc != null) {
1878 try {
1879 return new PrintStream(new BufferedOutputStream(fos, 128), true, enc);
1880 } catch (UnsupportedEncodingException uee) {}
1881 }
1882 return new PrintStream(new BufferedOutputStream(fos, 128), true);
1883 }
1884
1885 /**
1886 * Logs an exception/error at initialization time to stdout or stderr.
1887 *
1888 * @param printToStderr to print to stderr rather than stdout
1889 * @param printStackTrace to print the stack trace
1890 * @param msg the message to print before the exception, can be {@code null}
1891 * @param e the exception or error
1892 */
1893 private static void logInitException(boolean printToStderr,
1894 boolean printStackTrace,
1895 String msg,
1896 Throwable e) {
1897 if (VM.initLevel() < 1) {
1898 throw new InternalError("system classes not initialized");
1899 }
1900 PrintStream log = (printToStderr) ? err : out;
1901 if (msg != null) {
1902 log.println(msg);
1903 }
1904 if (printStackTrace) {
1905 e.printStackTrace(log);
1906 } else {
1907 log.println(e);
1908 for (Throwable suppressed : e.getSuppressed()) {
1909 log.println("Suppressed: " + suppressed);
1910 }
1911 Throwable cause = e.getCause();
1912 if (cause != null) {
1913 log.println("Caused by: " + cause);
1914 }
1915 }
1916 }
1917
1918 /**
1919 * Initialize the system class. Called after thread initialization.
1920 */
1921 private static void initPhase1() {
1922
1923 // VM might invoke JNU_NewStringPlatform() to set those encoding
1924 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1925 // during "props" initialization, in which it may need access, via
1926 // System.getProperty(), to the related system encoding property that
1927 // have been initialized (put into "props") at early stage of the
1928 // initialization. So make sure the "props" is available at the
1929 // very beginning of the initialization and all system properties to
1930 // be put into it directly.
1931 props = new Properties();
1932 initProperties(props); // initialized by the VM
1933
1934 // There are certain system configurations that may be controlled by
1935 // VM options such as the maximum amount of direct memory and
1936 // Integer cache size used to support the object identity semantics
1937 // of autoboxing. Typically, the library will obtain these values
1938 // from the properties set by the VM. If the properties are for
1939 // internal implementation use only, these properties should be
1940 // removed from the system properties.
1941 //
1942 // See java.lang.Integer.IntegerCache and the
1943 // VM.saveAndRemoveProperties method for example.
1944 //
1945 // Save a private copy of the system properties object that
1946 // can only be accessed by the internal implementation. Remove
1947 // certain system properties that are not intended for public access.
1948 VM.saveAndRemoveProperties(props);
1949
1950 lineSeparator = props.getProperty("line.separator");
1951 VersionProps.init();
1952
1953 FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
1954 FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
1955 FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
1956 setIn0(new BufferedInputStream(fdIn));
1957 setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
1958 setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
1959
1960 // Load the zip library now in order to keep java.util.zip.ZipFile
1961 // from trying to use itself to load this library later.
1962 loadLibrary("zip");
1963
1964 // Setup Java signal handlers for HUP, TERM, and INT (where available).
1965 Terminator.setup();
1966
1967 // Initialize any miscellaneous operating system settings that need to be
1968 // set for the class libraries. Currently this is no-op everywhere except
1969 // for Windows where the process-wide error mode is set before the java.io
1970 // classes are used.
1971 VM.initializeOSEnvironment();
1972
1973 // The main thread is not added to its thread group in the same
1974 // way as other threads; we must do it ourselves here.
1975 Thread current = Thread.currentThread();
1976 current.getThreadGroup().add(current);
1977
1978 // register shared secrets
1979 setJavaLangAccess();
1980
1981 // Subsystems that are invoked during initialization can invoke
1982 // VM.isBooted() in order to avoid doing things that should
1983 // wait until the VM is fully initialized. The initialization level
1984 // is incremented from 0 to 1 here to indicate the first phase of
1985 // initialization has completed.
1986 // IMPORTANT: Ensure that this remains the last initialization action!
1987 VM.initLevel(1);
1988 }
1989
1990 // @see #initPhase2()
1991 static ModuleLayer bootLayer;
1992
1993 /*
1994 * Invoked by VM. Phase 2 module system initialization.
1995 * Only classes in java.base can be loaded in this phase.
1996 *
1997 * @param printToStderr print exceptions to stderr rather than stdout
1998 * @param printStackTrace print stack trace when exception occurs
1999 *
2000 * @return JNI_OK for success, JNI_ERR for failure
2001 */
2002 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
2003 try {
2004 bootLayer = ModuleBootstrap.boot();
2005 } catch (Exception | Error e) {
2006 logInitException(printToStderr, printStackTrace,
2007 "Error occurred during initialization of boot layer", e);
2008 return -1; // JNI_ERR
2009 }
2010
2011 // module system initialized
2012 VM.initLevel(2);
2013
2014 return 0; // JNI_OK
2015 }
2016
2017 /*
2018 * Invoked by VM. Phase 3 is the final system initialization:
2019 * 1. set security manager
2020 * 2. set system class loader
2021 * 3. set TCCL
2022 *
2023 * This method must be called after the module system initialization.
2024 * The security manager and system class loader may be custom class from
2025 * the application classpath or modulepath.
2026 */
2027 private static void initPhase3() {
2028 // set security manager
2029 String cn = System.getProperty("java.security.manager");
2030 if (cn != null) {
2031 if (cn.isEmpty() || "default".equals(cn)) {
2032 System.setSecurityManager(new SecurityManager());
2033 } else {
2034 try {
2035 Class<?> c = Class.forName(cn, false, ClassLoader.getBuiltinAppClassLoader());
2036 Constructor<?> ctor = c.getConstructor();
2037 // Must be a public subclass of SecurityManager with
2038 // a public no-arg constructor
2039 if (!SecurityManager.class.isAssignableFrom(c) ||
2040 !Modifier.isPublic(c.getModifiers()) ||
2041 !Modifier.isPublic(ctor.getModifiers())) {
2042 throw new Error("Could not create SecurityManager: " + ctor.toString());
2043 }
2044 // custom security manager implementation may be in unnamed module
2045 // or a named module but non-exported package
2046 ctor.setAccessible(true);
2047 SecurityManager sm = (SecurityManager) ctor.newInstance();
2048 System.setSecurityManager(sm);
2049 } catch (Exception e) {
2050 throw new Error("Could not create SecurityManager", e);
2051 }
2052 }
2053 }
2054
2055 // initializing the system class loader
2056 VM.initLevel(3);
2057
2058 // system class loader initialized
2059 ClassLoader scl = ClassLoader.initSystemClassLoader();
2060
2061 // set TCCL
2062 Thread.currentThread().setContextClassLoader(scl);
2063
2064 // system is fully initialized
2065 VM.initLevel(4);
2066 }
2067
2068 private static void setJavaLangAccess() {
2069 // Allow privileged classes outside of java.lang
2070 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2071 public Method getMethodOrNull(Class<?> klass, String name, Class<?>... parameterTypes) {
2072 return klass.getMethodOrNull(name, parameterTypes);
2073 }
2074 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2075 return klass.getConstantPool();
2076 }
2077 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2078 return klass.casAnnotationType(oldType, newType);
2079 }
2080 public AnnotationType getAnnotationType(Class<?> klass) {
2081 return klass.getAnnotationType();
2082 }
2083 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2084 return klass.getDeclaredAnnotationMap();
2085 }
2086 public byte[] getRawClassAnnotations(Class<?> klass) {
2087 return klass.getRawAnnotations();
2088 }
2089 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2090 return klass.getRawTypeAnnotations();
2091 }
2092 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2093 return Class.getExecutableTypeAnnotationBytes(executable);
2094 }
2095 public <E extends Enum<E>>
2096 E[] getEnumConstantsShared(Class<E> klass) {
2097 return klass.getEnumConstantsShared();
2098 }
2099 public void blockedOn(Thread t, Interruptible b) {
2100 t.blockedOn(b);
2101 }
2102 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2103 Shutdown.add(slot, registerShutdownInProgress, hook);
2104 }
2105 public String newStringUnsafe(char[] chars) {
2106 return new String(chars, true);
2107 }
2108 public Thread newThreadWithAcc(Runnable target, AccessControlContext acc) {
2109 return new Thread(target, acc);
2110 }
2111 @SuppressWarnings("deprecation")
2112 public void invokeFinalize(Object o) throws Throwable {
2113 o.finalize();
2114 }
2115 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2116 return cl.createOrGetClassLoaderValueMap();
2117 }
2118 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2119 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2120 }
2121 public Class<?> findBootstrapClassOrNull(ClassLoader cl, String name) {
2122 return cl.findBootstrapClassOrNull(name);
2123 }
2124 public URL findResource(ClassLoader cl, String mn, String name) throws IOException {
2125 return cl.findResource(mn, name);
2126 }
2127 public Stream<Package> packages(ClassLoader cl) {
2128 return cl.packages();
2129 }
2130 public Package definePackage(ClassLoader cl, String name, Module module) {
2131 return cl.definePackage(name, module);
2132 }
2133 public String fastUUID(long lsb, long msb) {
2134 return Long.fastUUID(lsb, msb);
2135 }
2136 public void invalidatePackageAccessCache() {
2137 SecurityManager.invalidatePackageAccessCache();
2138 }
2139 public Module defineModule(ClassLoader loader,
2140 ModuleDescriptor descriptor,
2141 URI uri) {
2142 return new Module(null, loader, descriptor, uri);
2143 }
2144 public Module defineUnnamedModule(ClassLoader loader) {
2145 return new Module(loader);
2146 }
2147 public void addReads(Module m1, Module m2) {
2148 m1.implAddReads(m2);
2149 }
2150 public void addReadsAllUnnamed(Module m) {
2151 m.implAddReadsAllUnnamed();
2152 }
2153 public void addExports(Module m, String pn, Module other) {
2154 m.implAddExports(pn, other);
2155 }
2156 public void addExportsToAllUnnamed(Module m, String pn) {
2157 m.implAddExportsToAllUnnamed(pn);
2158 }
2159 public void addOpens(Module m, String pn, Module other) {
2160 m.implAddOpens(pn, other);
2161 }
2162 public void addOpensToAllUnnamed(Module m, String pn) {
2163 m.implAddOpensToAllUnnamed(pn);
2164 }
2165 public void addUses(Module m, Class<?> service) {
2166 m.implAddUses(service);
2167 }
2168 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2169 return layer.getServicesCatalog();
2170 }
2171 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2172 return layer.layers();
2173 }
2174 public Stream<ModuleLayer> layers(ClassLoader loader) {
2175 return ModuleLayer.layers(loader);
2176 }
2177 });
2178 }
2179 }