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