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 * @see Object#hashCode
538 * @see java.util.Objects#hashCode(Object)
539 */
540 @HotSpotIntrinsicCandidate
541 public static native int identityHashCode(Object x);
542
543 /**
544 * System properties. The following properties are guaranteed to be defined:
545 * <dl>
546 * <dt>java.version <dd>Java version number
547 * <dt>java.vendor <dd>Java vendor specific string
548 * <dt>java.vendor.url <dd>Java vendor URL
549 * <dt>java.home <dd>Java installation directory
550 * <dt>java.class.version <dd>Java class version number
551 * <dt>java.class.path <dd>Java classpath
552 * <dt>os.name <dd>Operating System Name
553 * <dt>os.arch <dd>Operating System Architecture
554 * <dt>os.version <dd>Operating System Version
555 * <dt>file.separator <dd>File separator ("/" on Unix)
556 * <dt>path.separator <dd>Path separator (":" on Unix)
557 * <dt>line.separator <dd>Line separator ("\n" on Unix)
558 * <dt>user.name <dd>User account name
559 * <dt>user.home <dd>User home directory
560 * <dt>user.dir <dd>User's current working directory
561 * </dl>
562 */
563
564 private static Properties props;
565 private static native Properties initProperties(Properties props);
566
567 /**
568 * Determines the current system properties.
569 * <p>
570 * First, if there is a security manager, its
571 * <code>checkPropertiesAccess</code> method is called with no
572 * arguments. This may result in a security exception.
573 * <p>
574 * The current set of system properties for use by the
575 * {@link #getProperty(String)} method is returned as a
576 * <code>Properties</code> object. If there is no current set of
577 * system properties, a set of system properties is first created and
578 * initialized. This set of system properties always includes values
579 * for the following keys:
580 * <table summary="Shows property keys and associated values">
581 * <tr><th>Key</th>
582 * <th>Description of Associated Value</th></tr>
583 * <tr><td><code>java.version</code></td>
584 * <td>Java Runtime Environment version which may be interpreted
585 * as a {@link Runtime.Version}</td></tr>
586 * <tr><td><code>java.vendor</code></td>
587 * <td>Java Runtime Environment vendor</td></tr>
588 * <tr><td><code>java.vendor.url</code></td>
589 * <td>Java vendor URL</td></tr>
590 * <tr><td><code>java.home</code></td>
591 * <td>Java installation directory</td></tr>
592 * <tr><td><code>java.vm.specification.version</code></td>
593 * <td>Java Virtual Machine specification version which may be
594 * interpreted as a {@link Runtime.Version}</td></tr>
595 * <tr><td><code>java.vm.specification.vendor</code></td>
596 * <td>Java Virtual Machine specification vendor</td></tr>
597 * <tr><td><code>java.vm.specification.name</code></td>
598 * <td>Java Virtual Machine specification name</td></tr>
599 * <tr><td><code>java.vm.version</code></td>
600 * <td>Java Virtual Machine implementation version which may be
601 * interpreted as a {@link Runtime.Version}</td></tr>
602 * <tr><td><code>java.vm.vendor</code></td>
603 * <td>Java Virtual Machine implementation vendor</td></tr>
604 * <tr><td><code>java.vm.name</code></td>
605 * <td>Java Virtual Machine implementation name</td></tr>
606 * <tr><td><code>java.specification.version</code></td>
607 * <td>Java Runtime Environment specification version which may be
608 * interpreted as a {@link Runtime.Version}</td></tr>
609 * <tr><td><code>java.specification.vendor</code></td>
610 * <td>Java Runtime Environment specification vendor</td></tr>
611 * <tr><td><code>java.specification.name</code></td>
612 * <td>Java Runtime Environment specification name</td></tr>
613 * <tr><td><code>java.class.version</code></td>
614 * <td>Java class format version number</td></tr>
615 * <tr><td><code>java.class.path</code></td>
616 * <td>Java class path</td></tr>
617 * <tr><td><code>java.library.path</code></td>
618 * <td>List of paths to search when loading libraries</td></tr>
619 * <tr><td><code>java.io.tmpdir</code></td>
620 * <td>Default temp file path</td></tr>
621 * <tr><td><code>java.compiler</code></td>
622 * <td>Name of JIT compiler to use</td></tr>
623 * <tr><td><code>os.name</code></td>
624 * <td>Operating system name</td></tr>
625 * <tr><td><code>os.arch</code></td>
626 * <td>Operating system architecture</td></tr>
627 * <tr><td><code>os.version</code></td>
628 * <td>Operating system version</td></tr>
629 * <tr><td><code>file.separator</code></td>
630 * <td>File separator ("/" on UNIX)</td></tr>
631 * <tr><td><code>path.separator</code></td>
632 * <td>Path separator (":" on UNIX)</td></tr>
633 * <tr><td><code>line.separator</code></td>
634 * <td>Line separator ("\n" on UNIX)</td></tr>
635 * <tr><td><code>user.name</code></td>
636 * <td>User's account name</td></tr>
637 * <tr><td><code>user.home</code></td>
638 * <td>User's home directory</td></tr>
639 * <tr><td><code>user.dir</code></td>
640 * <td>User's current working directory</td></tr>
641 * </table>
642 * <p>
643 * Multiple paths in a system property value are separated by the path
644 * separator character of the platform.
645 * <p>
646 * Note that even if the security manager does not permit the
647 * <code>getProperties</code> operation, it may choose to permit the
648 * {@link #getProperty(String)} operation.
649 *
650 * @implNote In addition to the standard system properties, the system
651 * properties may include the following keys:
652 * <table summary="Shows property keys and associated values">
653 * <tr><th>Key</th>
654 * <th>Description of Associated Value</th></tr>
655 * <tr><td>{@code jdk.module.path}</td>
656 * <td>The application module path</td></tr>
657 * <tr><td>{@code jdk.module.upgrade.path}</td>
658 * <td>The upgrade module path</td></tr>
659 * <tr><td>{@code jdk.module.main}</td>
660 * <td>The module name of the initial/main module</td></tr>
661 * <tr><td>{@code jdk.module.main.class}</td>
662 * <td>The main class name of the initial module</td></tr>
663 * </table>
664 *
665 * @return the system properties
666 * @exception SecurityException if a security manager exists and its
667 * <code>checkPropertiesAccess</code> method doesn't allow access
668 * to the system properties.
669 * @see #setProperties
670 * @see java.lang.SecurityException
671 * @see java.lang.SecurityManager#checkPropertiesAccess()
672 * @see java.util.Properties
673 */
674 public static Properties getProperties() {
675 SecurityManager sm = getSecurityManager();
676 if (sm != null) {
677 sm.checkPropertiesAccess();
678 }
679
680 return props;
681 }
682
683 /**
684 * Returns the system-dependent line separator string. It always
685 * returns the same value - the initial value of the {@linkplain
686 * #getProperty(String) system property} {@code line.separator}.
687 *
688 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
689 * Windows systems it returns {@code "\r\n"}.
690 *
691 * @return the system-dependent line separator string
692 * @since 1.7
693 */
694 public static String lineSeparator() {
695 return lineSeparator;
696 }
697
698 private static String lineSeparator;
699
700 /**
701 * Sets the system properties to the <code>Properties</code>
702 * argument.
703 * <p>
704 * First, if there is a security manager, its
705 * <code>checkPropertiesAccess</code> method is called with no
706 * arguments. This may result in a security exception.
707 * <p>
708 * The argument becomes the current set of system properties for use
709 * by the {@link #getProperty(String)} method. If the argument is
710 * <code>null</code>, then the current set of system properties is
711 * forgotten.
712 *
713 * @param props the new system properties.
714 * @exception SecurityException if a security manager exists and its
715 * <code>checkPropertiesAccess</code> method doesn't allow access
716 * to the system properties.
717 * @see #getProperties
718 * @see java.util.Properties
719 * @see java.lang.SecurityException
720 * @see java.lang.SecurityManager#checkPropertiesAccess()
721 */
722 public static void setProperties(Properties props) {
723 SecurityManager sm = getSecurityManager();
724 if (sm != null) {
725 sm.checkPropertiesAccess();
726 }
727 if (props == null) {
728 props = new Properties();
729 initProperties(props);
730 }
731 System.props = props;
732 }
733
734 /**
735 * Gets the system property indicated by the specified key.
736 * <p>
737 * First, if there is a security manager, its
738 * <code>checkPropertyAccess</code> method is called with the key as
739 * its argument. This may result in a SecurityException.
740 * <p>
741 * If there is no current set of system properties, a set of system
742 * properties is first created and initialized in the same manner as
743 * for the <code>getProperties</code> method.
744 *
745 * @param key the name of the system property.
746 * @return the string value of the system property,
747 * or <code>null</code> if there is no property with that key.
748 *
749 * @exception SecurityException if a security manager exists and its
750 * <code>checkPropertyAccess</code> method doesn't allow
751 * access to the specified system property.
752 * @exception NullPointerException if <code>key</code> is
753 * <code>null</code>.
754 * @exception IllegalArgumentException if <code>key</code> is empty.
755 * @see #setProperty
756 * @see java.lang.SecurityException
757 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
758 * @see java.lang.System#getProperties()
759 */
760 public static String getProperty(String key) {
761 checkKey(key);
762 SecurityManager sm = getSecurityManager();
763 if (sm != null) {
764 sm.checkPropertyAccess(key);
765 }
766
767 return props.getProperty(key);
768 }
769
770 /**
771 * Gets the system property indicated by the specified key.
772 * <p>
773 * First, if there is a security manager, its
774 * <code>checkPropertyAccess</code> method is called with the
775 * <code>key</code> as its argument.
776 * <p>
777 * If there is no current set of system properties, a set of system
778 * properties is first created and initialized in the same manner as
779 * for the <code>getProperties</code> method.
780 *
781 * @param key the name of the system property.
782 * @param def a default value.
783 * @return the string value of the system property,
784 * or the default value if there is no property with that key.
785 *
786 * @exception SecurityException if a security manager exists and its
787 * <code>checkPropertyAccess</code> method doesn't allow
788 * access to the specified system property.
789 * @exception NullPointerException if <code>key</code> is
790 * <code>null</code>.
791 * @exception IllegalArgumentException if <code>key</code> is empty.
792 * @see #setProperty
793 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
794 * @see java.lang.System#getProperties()
795 */
796 public static String getProperty(String key, String def) {
797 checkKey(key);
798 SecurityManager sm = getSecurityManager();
799 if (sm != null) {
800 sm.checkPropertyAccess(key);
801 }
802
803 return props.getProperty(key, def);
804 }
805
806 /**
807 * Sets the system property indicated by the specified key.
808 * <p>
809 * First, if a security manager exists, its
810 * <code>SecurityManager.checkPermission</code> method
811 * is called with a <code>PropertyPermission(key, "write")</code>
812 * permission. This may result in a SecurityException being thrown.
813 * If no exception is thrown, the specified property is set to the given
814 * value.
815 *
816 * @param key the name of the system property.
817 * @param value the value of the system property.
818 * @return the previous value of the system property,
819 * or <code>null</code> if it did not have one.
820 *
821 * @exception SecurityException if a security manager exists and its
822 * <code>checkPermission</code> method doesn't allow
823 * setting of the specified property.
824 * @exception NullPointerException if <code>key</code> or
825 * <code>value</code> is <code>null</code>.
826 * @exception IllegalArgumentException if <code>key</code> is empty.
827 * @see #getProperty
828 * @see java.lang.System#getProperty(java.lang.String)
829 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
830 * @see java.util.PropertyPermission
831 * @see SecurityManager#checkPermission
832 * @since 1.2
833 */
834 public static String setProperty(String key, String value) {
835 checkKey(key);
836 SecurityManager sm = getSecurityManager();
837 if (sm != null) {
838 sm.checkPermission(new PropertyPermission(key,
839 SecurityConstants.PROPERTY_WRITE_ACTION));
840 }
841
842 return (String) props.setProperty(key, value);
843 }
844
845 /**
846 * Removes the system property indicated by the specified key.
847 * <p>
848 * First, if a security manager exists, its
849 * <code>SecurityManager.checkPermission</code> method
850 * is called with a <code>PropertyPermission(key, "write")</code>
851 * permission. This may result in a SecurityException being thrown.
852 * If no exception is thrown, the specified property is removed.
853 *
854 * @param key the name of the system property to be removed.
855 * @return the previous string value of the system property,
856 * or <code>null</code> if there was no property with that key.
857 *
858 * @exception SecurityException if a security manager exists and its
859 * <code>checkPropertyAccess</code> method doesn't allow
860 * access to the specified system property.
861 * @exception NullPointerException if <code>key</code> is
862 * <code>null</code>.
863 * @exception IllegalArgumentException if <code>key</code> is empty.
864 * @see #getProperty
865 * @see #setProperty
866 * @see java.util.Properties
867 * @see java.lang.SecurityException
868 * @see java.lang.SecurityManager#checkPropertiesAccess()
869 * @since 1.5
870 */
871 public static String clearProperty(String key) {
872 checkKey(key);
873 SecurityManager sm = getSecurityManager();
874 if (sm != null) {
875 sm.checkPermission(new PropertyPermission(key, "write"));
876 }
877
878 return (String) props.remove(key);
879 }
880
881 private static void checkKey(String key) {
882 if (key == null) {
883 throw new NullPointerException("key can't be null");
884 }
885 if (key.equals("")) {
886 throw new IllegalArgumentException("key can't be empty");
887 }
888 }
889
890 /**
891 * Gets the value of the specified environment variable. An
892 * environment variable is a system-dependent external named
893 * value.
894 *
895 * <p>If a security manager exists, its
896 * {@link SecurityManager#checkPermission checkPermission}
897 * method is called with a
898 * <code>{@link RuntimePermission}("getenv."+name)</code>
899 * permission. This may result in a {@link SecurityException}
900 * being thrown. If no exception is thrown the value of the
901 * variable <code>name</code> is returned.
902 *
903 * <p><a id="EnvironmentVSSystemProperties"><i>System
904 * properties</i> and <i>environment variables</i></a> are both
905 * conceptually mappings between names and values. Both
906 * mechanisms can be used to pass user-defined information to a
907 * Java process. Environment variables have a more global effect,
908 * because they are visible to all descendants of the process
909 * which defines them, not just the immediate Java subprocess.
910 * They can have subtly different semantics, such as case
911 * insensitivity, on different operating systems. For these
912 * reasons, environment variables are more likely to have
913 * unintended side effects. It is best to use system properties
914 * where possible. Environment variables should be used when a
915 * global effect is desired, or when an external system interface
916 * requires an environment variable (such as <code>PATH</code>).
917 *
918 * <p>On UNIX systems the alphabetic case of <code>name</code> is
919 * typically significant, while on Microsoft Windows systems it is
920 * typically not. For example, the expression
921 * <code>System.getenv("FOO").equals(System.getenv("foo"))</code>
922 * is likely to be true on Microsoft Windows.
923 *
924 * @param name the name of the environment variable
925 * @return the string value of the variable, or <code>null</code>
926 * if the variable is not defined in the system environment
927 * @throws NullPointerException if <code>name</code> is <code>null</code>
928 * @throws SecurityException
929 * if a security manager exists and its
930 * {@link SecurityManager#checkPermission checkPermission}
931 * method doesn't allow access to the environment variable
932 * <code>name</code>
933 * @see #getenv()
934 * @see ProcessBuilder#environment()
935 */
936 public static String getenv(String name) {
937 SecurityManager sm = getSecurityManager();
938 if (sm != null) {
939 sm.checkPermission(new RuntimePermission("getenv."+name));
940 }
941
942 return ProcessEnvironment.getenv(name);
943 }
944
945
946 /**
947 * Returns an unmodifiable string map view of the current system environment.
948 * The environment is a system-dependent mapping from names to
949 * values which is passed from parent to child processes.
950 *
951 * <p>If the system does not support environment variables, an
952 * empty map is returned.
953 *
954 * <p>The returned map will never contain null keys or values.
955 * Attempting to query the presence of a null key or value will
956 * throw a {@link NullPointerException}. Attempting to query
957 * the presence of a key or value which is not of type
958 * {@link String} will throw a {@link ClassCastException}.
959 *
960 * <p>The returned map and its collection views may not obey the
961 * general contract of the {@link Object#equals} and
962 * {@link Object#hashCode} methods.
963 *
964 * <p>The returned map is typically case-sensitive on all platforms.
965 *
966 * <p>If a security manager exists, its
967 * {@link SecurityManager#checkPermission checkPermission}
968 * method is called with a
969 * <code>{@link RuntimePermission}("getenv.*")</code>
970 * permission. This may result in a {@link SecurityException} being
971 * thrown.
972 *
973 * <p>When passing information to a Java subprocess,
974 * <a href=#EnvironmentVSSystemProperties>system properties</a>
975 * are generally preferred over environment variables.
976 *
977 * @return the environment as a map of variable names to values
978 * @throws SecurityException
979 * if a security manager exists and its
980 * {@link SecurityManager#checkPermission checkPermission}
981 * method doesn't allow access to the process environment
982 * @see #getenv(String)
983 * @see ProcessBuilder#environment()
984 * @since 1.5
985 */
986 public static java.util.Map<String,String> getenv() {
987 SecurityManager sm = getSecurityManager();
988 if (sm != null) {
989 sm.checkPermission(new RuntimePermission("getenv.*"));
990 }
991
992 return ProcessEnvironment.getenv();
993 }
994
995 /**
996 * {@code System.Logger} instances log messages that will be
997 * routed to the underlying logging framework the {@link System.LoggerFinder
998 * LoggerFinder} uses.
999 * <p>
1000 * {@code System.Logger} instances are typically obtained from
1001 * the {@link java.lang.System System} class, by calling
1002 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
1003 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1004 * System.getLogger(loggerName, bundle)}.
1005 *
1006 * @see java.lang.System#getLogger(java.lang.String)
1007 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1008 * @see java.lang.System.LoggerFinder
1009 *
1010 * @since 9
1011 *
1012 */
1013 public interface Logger {
1014
1015 /**
1016 * System {@linkplain Logger loggers} levels.
1017 * <p>
1018 * A level has a {@linkplain #getName() name} and {@linkplain
1019 * #getSeverity() severity}.
1020 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
1021 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
1022 * by order of increasing severity.
1023 * <br>
1024 * {@link #ALL} and {@link #OFF}
1025 * are simple markers with severities mapped respectively to
1026 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
1027 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
1028 * <p>
1029 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
1030 * <p>
1031 * {@linkplain System.Logger.Level System logger levels} are mapped to
1032 * {@linkplain java.util.logging.Level java.util.logging levels}
1033 * of corresponding severity.
1034 * <br>The mapping is as follows:
1035 * <br><br>
1036 * <table border="1">
1037 * <caption>System.Logger Severity Level Mapping</caption>
1038 * <tr><td><b>System.Logger Levels</b></td>
1039 * <td>{@link Logger.Level#ALL ALL}</td>
1040 * <td>{@link Logger.Level#TRACE TRACE}</td>
1041 * <td>{@link Logger.Level#DEBUG DEBUG}</td>
1042 * <td>{@link Logger.Level#INFO INFO}</td>
1043 * <td>{@link Logger.Level#WARNING WARNING}</td>
1044 * <td>{@link Logger.Level#ERROR ERROR}</td>
1045 * <td>{@link Logger.Level#OFF OFF}</td>
1046 * </tr>
1047 * <tr><td><b>java.util.logging Levels</b></td>
1048 * <td>{@link java.util.logging.Level#ALL ALL}</td>
1049 * <td>{@link java.util.logging.Level#FINER FINER}</td>
1050 * <td>{@link java.util.logging.Level#FINE FINE}</td>
1051 * <td>{@link java.util.logging.Level#INFO INFO}</td>
1052 * <td>{@link java.util.logging.Level#WARNING WARNING}</td>
1053 * <td>{@link java.util.logging.Level#SEVERE SEVERE}</td>
1054 * <td>{@link java.util.logging.Level#OFF OFF}</td>
1055 * </tr>
1056 * </table>
1057 *
1058 * @since 9
1059 *
1060 * @see java.lang.System.LoggerFinder
1061 * @see java.lang.System.Logger
1062 */
1063 public enum Level {
1064
1065 // for convenience, we're reusing java.util.logging.Level int values
1066 // the mapping logic in sun.util.logging.PlatformLogger depends
1067 // on this.
1068 /**
1069 * A marker to indicate that all levels are enabled.
1070 * This level {@linkplain #getSeverity() severity} is
1071 * {@link Integer#MIN_VALUE}.
1072 */
1073 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
1074 /**
1075 * {@code TRACE} level: usually used to log diagnostic information.
1076 * This level {@linkplain #getSeverity() severity} is
1077 * {@code 400}.
1078 */
1079 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1080 /**
1081 * {@code DEBUG} level: usually used to log debug information traces.
1082 * This level {@linkplain #getSeverity() severity} is
1083 * {@code 500}.
1084 */
1085 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1086 /**
1087 * {@code INFO} level: usually used to log information messages.
1088 * This level {@linkplain #getSeverity() severity} is
1089 * {@code 800}.
1090 */
1091 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1092 /**
1093 * {@code WARNING} level: usually used to log warning messages.
1094 * This level {@linkplain #getSeverity() severity} is
1095 * {@code 900}.
1096 */
1097 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1098 /**
1099 * {@code ERROR} level: usually used to log error messages.
1100 * This level {@linkplain #getSeverity() severity} is
1101 * {@code 1000}.
1102 */
1103 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1104 /**
1105 * A marker to indicate that all levels are disabled.
1106 * This level {@linkplain #getSeverity() severity} is
1107 * {@link Integer#MAX_VALUE}.
1108 */
1109 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1110
1111 private final int severity;
1112
1113 private Level(int severity) {
1114 this.severity = severity;
1115 }
1116
1117 /**
1118 * Returns the name of this level.
1119 * @return this level {@linkplain #name()}.
1120 */
1121 public final String getName() {
1122 return name();
1123 }
1124
1125 /**
1126 * Returns the severity of this level.
1127 * A higher severity means a more severe condition.
1128 * @return this level severity.
1129 */
1130 public final int getSeverity() {
1131 return severity;
1132 }
1133 }
1134
1135 /**
1136 * Returns the name of this logger.
1137 *
1138 * @return the logger name.
1139 */
1140 public String getName();
1141
1142 /**
1143 * Checks if a message of the given level would be logged by
1144 * this logger.
1145 *
1146 * @param level the log message level.
1147 * @return {@code true} if the given log message level is currently
1148 * being logged.
1149 *
1150 * @throws NullPointerException if {@code level} is {@code null}.
1151 */
1152 public boolean isLoggable(Level level);
1153
1154 /**
1155 * Logs a message.
1156 *
1157 * @implSpec The default implementation for this method calls
1158 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1159 *
1160 * @param level the log message level.
1161 * @param msg the string message (or a key in the message catalog, if
1162 * this logger is a {@link
1163 * LoggerFinder#getLocalizedLogger(java.lang.String,
1164 * java.util.ResourceBundle, java.lang.Module) localized logger});
1165 * can be {@code null}.
1166 *
1167 * @throws NullPointerException if {@code level} is {@code null}.
1168 */
1169 public default void log(Level level, String msg) {
1170 log(level, (ResourceBundle) null, msg, (Object[]) null);
1171 }
1172
1173 /**
1174 * Logs a lazily supplied message.
1175 * <p>
1176 * If the logger is currently enabled for the given log message level
1177 * then a message is logged that is the result produced by the
1178 * given supplier function. Otherwise, the supplier is not operated on.
1179 *
1180 * @implSpec When logging is enabled for the given level, the default
1181 * implementation for this method calls
1182 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1183 *
1184 * @param level the log message level.
1185 * @param msgSupplier a supplier function that produces a message.
1186 *
1187 * @throws NullPointerException if {@code level} is {@code null},
1188 * or {@code msgSupplier} is {@code null}.
1189 */
1190 public default void log(Level level, Supplier<String> msgSupplier) {
1191 Objects.requireNonNull(msgSupplier);
1192 if (isLoggable(Objects.requireNonNull(level))) {
1193 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1194 }
1195 }
1196
1197 /**
1198 * Logs a message produced from the given object.
1199 * <p>
1200 * If the logger is currently enabled for the given log message level then
1201 * a message is logged that, by default, is the result produced from
1202 * calling toString on the given object.
1203 * Otherwise, the object is not operated on.
1204 *
1205 * @implSpec When logging is enabled for the given level, the default
1206 * implementation for this method calls
1207 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1208 *
1209 * @param level the log message level.
1210 * @param obj the object to log.
1211 *
1212 * @throws NullPointerException if {@code level} is {@code null}, or
1213 * {@code obj} is {@code null}.
1214 */
1215 public default void log(Level level, Object obj) {
1216 Objects.requireNonNull(obj);
1217 if (isLoggable(Objects.requireNonNull(level))) {
1218 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1219 }
1220 }
1221
1222 /**
1223 * Logs a message associated with a given throwable.
1224 *
1225 * @implSpec The default implementation for this method calls
1226 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1227 *
1228 * @param level the log message level.
1229 * @param msg the string message (or a key in the message catalog, if
1230 * this logger is a {@link
1231 * LoggerFinder#getLocalizedLogger(java.lang.String,
1232 * java.util.ResourceBundle, java.lang.Module) localized logger});
1233 * can be {@code null}.
1234 * @param thrown a {@code Throwable} associated with the log message;
1235 * can be {@code null}.
1236 *
1237 * @throws NullPointerException if {@code level} is {@code null}.
1238 */
1239 public default void log(Level level, String msg, Throwable thrown) {
1240 this.log(level, null, msg, thrown);
1241 }
1242
1243 /**
1244 * Logs a lazily supplied message associated with a given throwable.
1245 * <p>
1246 * If the logger is currently enabled for the given log message level
1247 * then a message is logged that is the result produced by the
1248 * given supplier function. Otherwise, the supplier is not operated on.
1249 *
1250 * @implSpec When logging is enabled for the given level, the default
1251 * implementation for this method calls
1252 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1253 *
1254 * @param level one of the log message level identifiers.
1255 * @param msgSupplier a supplier function that produces a message.
1256 * @param thrown a {@code Throwable} associated with log message;
1257 * can be {@code null}.
1258 *
1259 * @throws NullPointerException if {@code level} is {@code null}, or
1260 * {@code msgSupplier} is {@code null}.
1261 */
1262 public default void log(Level level, Supplier<String> msgSupplier,
1263 Throwable thrown) {
1264 Objects.requireNonNull(msgSupplier);
1265 if (isLoggable(Objects.requireNonNull(level))) {
1266 this.log(level, null, msgSupplier.get(), thrown);
1267 }
1268 }
1269
1270 /**
1271 * Logs a message with an optional list of parameters.
1272 *
1273 * @implSpec The default implementation for this method calls
1274 * {@code this.log(level, (ResourceBundle)null, format, params);}
1275 *
1276 * @param level one of the log message level identifiers.
1277 * @param format the string message format in {@link
1278 * java.text.MessageFormat} format, (or a key in the message
1279 * catalog, if this logger is a {@link
1280 * LoggerFinder#getLocalizedLogger(java.lang.String,
1281 * java.util.ResourceBundle, java.lang.Module) localized logger});
1282 * can be {@code null}.
1283 * @param params an optional list of parameters to the message (may be
1284 * none).
1285 *
1286 * @throws NullPointerException if {@code level} is {@code null}.
1287 */
1288 public default void log(Level level, String format, Object... params) {
1289 this.log(level, null, format, params);
1290 }
1291
1292 /**
1293 * Logs a localized message associated with a given throwable.
1294 * <p>
1295 * If the given resource bundle is non-{@code null}, the {@code msg}
1296 * string is localized using the given resource bundle.
1297 * Otherwise the {@code msg} string is not localized.
1298 *
1299 * @param level the log message level.
1300 * @param bundle a resource bundle to localize {@code msg}; can be
1301 * {@code null}.
1302 * @param msg the string message (or a key in the message catalog,
1303 * if {@code bundle} is not {@code null}); can be {@code null}.
1304 * @param thrown a {@code Throwable} associated with the log message;
1305 * can be {@code null}.
1306 *
1307 * @throws NullPointerException if {@code level} is {@code null}.
1308 */
1309 public void log(Level level, ResourceBundle bundle, String msg,
1310 Throwable thrown);
1311
1312 /**
1313 * Logs a message with resource bundle and an optional list of
1314 * parameters.
1315 * <p>
1316 * If the given resource bundle is non-{@code null}, the {@code format}
1317 * string is localized using the given resource bundle.
1318 * Otherwise the {@code format} string is not localized.
1319 *
1320 * @param level the log message level.
1321 * @param bundle a resource bundle to localize {@code format}; can be
1322 * {@code null}.
1323 * @param format the string message format in {@link
1324 * java.text.MessageFormat} format, (or a key in the message
1325 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1326 * @param params an optional list of parameters to the message (may be
1327 * none).
1328 *
1329 * @throws NullPointerException if {@code level} is {@code null}.
1330 */
1331 public void log(Level level, ResourceBundle bundle, String format,
1332 Object... params);
1333
1334
1335 }
1336
1337 /**
1338 * The {@code LoggerFinder} service is responsible for creating, managing,
1339 * and configuring loggers to the underlying framework it uses.
1340 * <p>
1341 * A logger finder is a concrete implementation of this class that has a
1342 * zero-argument constructor and implements the abstract methods defined
1343 * by this class.
1344 * The loggers returned from a logger finder are capable of routing log
1345 * messages to the logging backend this provider supports.
1346 * A given invocation of the Java Runtime maintains a single
1347 * system-wide LoggerFinder instance that is loaded as follows:
1348 * <ul>
1349 * <li>First it finds any custom {@code LoggerFinder} provider
1350 * using the {@link java.util.ServiceLoader} facility with the
1351 * {@linkplain ClassLoader#getSystemClassLoader() system class
1352 * loader}.</li>
1353 * <li>If no {@code LoggerFinder} provider is found, the system default
1354 * {@code LoggerFinder} implementation will be used.</li>
1355 * </ul>
1356 * <p>
1357 * An application can replace the logging backend
1358 * <i>even when the java.logging module is present</i>, by simply providing
1359 * and declaring an implementation of the {@link LoggerFinder} service.
1360 * <p>
1361 * <b>Default Implementation</b>
1362 * <p>
1363 * The system default {@code LoggerFinder} implementation uses
1364 * {@code java.util.logging} as the backend framework when the
1365 * {@code java.logging} module is present.
1366 * It returns a {@linkplain System.Logger logger} instance
1367 * that will route log messages to a {@link java.util.logging.Logger
1368 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1369 * present, the default implementation will return a simple logger
1370 * instance that will route log messages of {@code INFO} level and above to
1371 * the console ({@code System.err}).
1372 * <p>
1373 * <b>Logging Configuration</b>
1374 * <p>
1375 * {@linkplain Logger Logger} instances obtained from the
1376 * {@code LoggerFinder} factory methods are not directly configurable by
1377 * the application. Configuration is the responsibility of the underlying
1378 * logging backend, and usually requires using APIs specific to that backend.
1379 * <p>For the default {@code LoggerFinder} implementation
1380 * using {@code java.util.logging} as its backend, refer to
1381 * {@link java.util.logging java.util.logging} for logging configuration.
1382 * For the default {@code LoggerFinder} implementation returning simple loggers
1383 * when the {@code java.logging} module is absent, the configuration
1384 * is implementation dependent.
1385 * <p>
1386 * Usually an application that uses a logging framework will log messages
1387 * through a logger facade defined (or supported) by that framework.
1388 * Applications that wish to use an external framework should log
1389 * through the facade associated with that framework.
1390 * <p>
1391 * A system class that needs to log messages will typically obtain
1392 * a {@link System.Logger} instance to route messages to the logging
1393 * framework selected by the application.
1394 * <p>
1395 * Libraries and classes that only need loggers to produce log messages
1396 * should not attempt to configure loggers by themselves, as that
1397 * would make them dependent from a specific implementation of the
1398 * {@code LoggerFinder} service.
1399 * <p>
1400 * In addition, when a security manager is present, loggers provided to
1401 * system classes should not be directly configurable through the logging
1402 * backend without requiring permissions.
1403 * <br>
1404 * It is the responsibility of the provider of
1405 * the concrete {@code LoggerFinder} implementation to ensure that
1406 * these loggers are not configured by untrusted code without proper
1407 * permission checks, as configuration performed on such loggers usually
1408 * affects all applications in the same Java Runtime.
1409 * <p>
1410 * <b>Message Levels and Mapping to backend levels</b>
1411 * <p>
1412 * A logger finder is responsible for mapping from a {@code
1413 * System.Logger.Level} to a level supported by the logging backend it uses.
1414 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1415 * maps {@code System.Logger} levels to
1416 * {@linkplain java.util.logging.Level java.util.logging} levels
1417 * of corresponding severity - as described in {@link Logger.Level
1418 * Logger.Level}.
1419 *
1420 * @see java.lang.System
1421 * @see java.lang.System.Logger
1422 *
1423 * @since 9
1424 */
1425 public static abstract class LoggerFinder {
1426 /**
1427 * The {@code RuntimePermission("loggerFinder")} is
1428 * necessary to subclass and instantiate the {@code LoggerFinder} class,
1429 * as well as to obtain loggers from an instance of that class.
1430 */
1431 static final RuntimePermission LOGGERFINDER_PERMISSION =
1432 new RuntimePermission("loggerFinder");
1433
1434 /**
1435 * Creates a new instance of {@code LoggerFinder}.
1436 *
1437 * @implNote It is recommended that a {@code LoggerFinder} service
1438 * implementation does not perform any heavy initialization in its
1439 * constructor, in order to avoid possible risks of deadlock or class
1440 * loading cycles during the instantiation of the service provider.
1441 *
1442 * @throws SecurityException if a security manager is present and its
1443 * {@code checkPermission} method doesn't allow the
1444 * {@code RuntimePermission("loggerFinder")}.
1445 */
1446 protected LoggerFinder() {
1447 this(checkPermission());
1448 }
1449
1450 private LoggerFinder(Void unused) {
1451 // nothing to do.
1452 }
1453
1454 private static Void checkPermission() {
1455 final SecurityManager sm = System.getSecurityManager();
1456 if (sm != null) {
1457 sm.checkPermission(LOGGERFINDER_PERMISSION);
1458 }
1459 return null;
1460 }
1461
1462 /**
1463 * Returns an instance of {@link Logger Logger}
1464 * for the given {@code module}.
1465 *
1466 * @param name the name of the logger.
1467 * @param module the module for which the logger is being requested.
1468 *
1469 * @return a {@link Logger logger} suitable for use within the given
1470 * module.
1471 * @throws NullPointerException if {@code name} is {@code null} or
1472 * {@code module} is {@code null}.
1473 * @throws SecurityException if a security manager is present and its
1474 * {@code checkPermission} method doesn't allow the
1475 * {@code RuntimePermission("loggerFinder")}.
1476 */
1477 public abstract Logger getLogger(String name, Module module);
1478
1479 /**
1480 * Returns a localizable instance of {@link Logger Logger}
1481 * for the given {@code module}.
1482 * The returned logger will use the provided resource bundle for
1483 * message localization.
1484 *
1485 * @implSpec By default, this method calls {@link
1486 * #getLogger(java.lang.String, java.lang.Module)
1487 * this.getLogger(name, module)} to obtain a logger, then wraps that
1488 * logger in a {@link Logger} instance where all methods that do not
1489 * take a {@link ResourceBundle} as parameter are redirected to one
1490 * which does - passing the given {@code bundle} for
1491 * localization. So for instance, a call to {@link
1492 * Logger#log(Level, String) Logger.log(Level.INFO, msg)}
1493 * will end up as a call to {@link
1494 * Logger#log(Level, ResourceBundle, String, Object...)
1495 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1496 * logger instance.
1497 * Note however that by default, string messages returned by {@link
1498 * java.util.function.Supplier Supplier<String>} will not be
1499 * localized, as it is assumed that such strings are messages which are
1500 * already constructed, rather than keys in a resource bundle.
1501 * <p>
1502 * An implementation of {@code LoggerFinder} may override this method,
1503 * for example, when the underlying logging backend provides its own
1504 * mechanism for localizing log messages, then such a
1505 * {@code LoggerFinder} would be free to return a logger
1506 * that makes direct use of the mechanism provided by the backend.
1507 *
1508 * @param name the name of the logger.
1509 * @param bundle a resource bundle; can be {@code null}.
1510 * @param module the module for which the logger is being requested.
1511 * @return an instance of {@link Logger Logger} which will use the
1512 * provided resource bundle for message localization.
1513 *
1514 * @throws NullPointerException if {@code name} is {@code null} or
1515 * {@code module} is {@code null}.
1516 * @throws SecurityException if a security manager is present and its
1517 * {@code checkPermission} method doesn't allow the
1518 * {@code RuntimePermission("loggerFinder")}.
1519 */
1520 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1521 Module module) {
1522 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1523 }
1524
1525 /**
1526 * Returns the {@code LoggerFinder} instance. There is one
1527 * single system-wide {@code LoggerFinder} instance in
1528 * the Java Runtime. See the class specification of how the
1529 * {@link LoggerFinder LoggerFinder} implementation is located and
1530 * loaded.
1531
1532 * @return the {@link LoggerFinder LoggerFinder} instance.
1533 * @throws SecurityException if a security manager is present and its
1534 * {@code checkPermission} method doesn't allow the
1535 * {@code RuntimePermission("loggerFinder")}.
1536 */
1537 public static LoggerFinder getLoggerFinder() {
1538 final SecurityManager sm = System.getSecurityManager();
1539 if (sm != null) {
1540 sm.checkPermission(LOGGERFINDER_PERMISSION);
1541 }
1542 return accessProvider();
1543 }
1544
1545
1546 private static volatile LoggerFinder service;
1547 static LoggerFinder accessProvider() {
1548 // We do not need to synchronize: LoggerFinderLoader will
1549 // always return the same instance, so if we don't have it,
1550 // just fetch it again.
1551 if (service == null) {
1552 PrivilegedAction<LoggerFinder> pa =
1553 () -> LoggerFinderLoader.getLoggerFinder();
1554 service = AccessController.doPrivileged(pa, null,
1555 LOGGERFINDER_PERMISSION);
1556 }
1557 return service;
1558 }
1559
1560 }
1561
1562
1563 /**
1564 * Returns an instance of {@link Logger Logger} for the caller's
1565 * use.
1566 *
1567 * @implSpec
1568 * Instances returned by this method route messages to loggers
1569 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1570 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1571 * {@code module} is the caller's module.
1572 * In cases where {@code System.getLogger} is called from a context where
1573 * there is no caller frame on the stack (e.g when called directly
1574 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1575 * To obtain a logger in such a context, use an auxiliary class that will
1576 * implicitly be identified as the caller, or use the system {@link
1577 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1578 * Note that doing the latter may eagerly initialize the underlying
1579 * logging system.
1580 *
1581 * @apiNote
1582 * This method may defer calling the {@link
1583 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1584 * LoggerFinder.getLogger} method to create an actual logger supplied by
1585 * the logging backend, for instance, to allow loggers to be obtained during
1586 * the system initialization time.
1587 *
1588 * @param name the name of the logger.
1589 * @return an instance of {@link Logger} that can be used by the calling
1590 * class.
1591 * @throws NullPointerException if {@code name} is {@code null}.
1592 * @throws IllegalCallerException if there is no Java caller frame on the
1593 * stack.
1594 *
1595 * @since 9
1596 */
1597 @CallerSensitive
1598 public static Logger getLogger(String name) {
1599 Objects.requireNonNull(name);
1600 final Class<?> caller = Reflection.getCallerClass();
1601 if (caller == null) {
1602 throw new IllegalCallerException("no caller frame");
1603 }
1604 return LazyLoggers.getLogger(name, caller.getModule());
1605 }
1606
1607 /**
1608 * Returns a localizable instance of {@link Logger
1609 * Logger} for the caller's use.
1610 * The returned logger will use the provided resource bundle for message
1611 * localization.
1612 *
1613 * @implSpec
1614 * The returned logger will perform message localization as specified
1615 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1616 * java.util.ResourceBundle, java.lang.Module)
1617 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1618 * {@code module} is the caller's module.
1619 * In cases where {@code System.getLogger} is called from a context where
1620 * there is no caller frame on the stack (e.g when called directly
1621 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1622 * To obtain a logger in such a context, use an auxiliary class that
1623 * will implicitly be identified as the caller, or use the system {@link
1624 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1625 * Note that doing the latter may eagerly initialize the underlying
1626 * logging system.
1627 *
1628 * @apiNote
1629 * This method is intended to be used after the system is fully initialized.
1630 * This method may trigger the immediate loading and initialization
1631 * of the {@link LoggerFinder} service, which may cause issues if the
1632 * Java Runtime is not ready to initialize the concrete service
1633 * implementation yet.
1634 * System classes which may be loaded early in the boot sequence and
1635 * need to log localized messages should create a logger using
1636 * {@link #getLogger(java.lang.String)} and then use the log methods that
1637 * take a resource bundle as parameter.
1638 *
1639 * @param name the name of the logger.
1640 * @param bundle a resource bundle.
1641 * @return an instance of {@link Logger} which will use the provided
1642 * resource bundle for message localization.
1643 * @throws NullPointerException if {@code name} is {@code null} or
1644 * {@code bundle} is {@code null}.
1645 * @throws IllegalCallerException if there is no Java caller frame on the
1646 * stack.
1647 *
1648 * @since 9
1649 */
1650 @CallerSensitive
1651 public static Logger getLogger(String name, ResourceBundle bundle) {
1652 final ResourceBundle rb = Objects.requireNonNull(bundle);
1653 Objects.requireNonNull(name);
1654 final Class<?> caller = Reflection.getCallerClass();
1655 if (caller == null) {
1656 throw new IllegalCallerException("no caller frame");
1657 }
1658 final SecurityManager sm = System.getSecurityManager();
1659 // We don't use LazyLoggers if a resource bundle is specified.
1660 // Bootstrap sensitive classes in the JDK do not use resource bundles
1661 // when logging. This could be revisited later, if it needs to.
1662 if (sm != null) {
1663 final PrivilegedAction<Logger> pa =
1664 () -> LoggerFinder.accessProvider()
1665 .getLocalizedLogger(name, rb, caller.getModule());
1666 return AccessController.doPrivileged(pa, null,
1667 LoggerFinder.LOGGERFINDER_PERMISSION);
1668 }
1669 return LoggerFinder.accessProvider()
1670 .getLocalizedLogger(name, rb, caller.getModule());
1671 }
1672
1673 /**
1674 * Terminates the currently running Java Virtual Machine. The
1675 * argument serves as a status code; by convention, a nonzero status
1676 * code indicates abnormal termination.
1677 * <p>
1678 * This method calls the <code>exit</code> method in class
1679 * <code>Runtime</code>. This method never returns normally.
1680 * <p>
1681 * The call <code>System.exit(n)</code> is effectively equivalent to
1682 * the call:
1683 * <blockquote><pre>
1684 * Runtime.getRuntime().exit(n)
1685 * </pre></blockquote>
1686 *
1687 * @param status exit status.
1688 * @throws SecurityException
1689 * if a security manager exists and its <code>checkExit</code>
1690 * method doesn't allow exit with the specified status.
1691 * @see java.lang.Runtime#exit(int)
1692 */
1693 public static void exit(int status) {
1694 Runtime.getRuntime().exit(status);
1695 }
1696
1697 /**
1698 * Runs the garbage collector.
1699 * <p>
1700 * Calling the <code>gc</code> method suggests that the Java Virtual
1701 * Machine expend effort toward recycling unused objects in order to
1702 * make the memory they currently occupy available for quick reuse.
1703 * When control returns from the method call, the Java Virtual
1704 * Machine has made a best effort to reclaim space from all discarded
1705 * objects.
1706 * <p>
1707 * The call <code>System.gc()</code> is effectively equivalent to the
1708 * call:
1709 * <blockquote><pre>
1710 * Runtime.getRuntime().gc()
1711 * </pre></blockquote>
1712 *
1713 * @see java.lang.Runtime#gc()
1714 */
1715 public static void gc() {
1716 Runtime.getRuntime().gc();
1717 }
1718
1719 /**
1720 * Runs the finalization methods of any objects pending finalization.
1721 * <p>
1722 * Calling this method suggests that the Java Virtual Machine expend
1723 * effort toward running the <code>finalize</code> methods of objects
1724 * that have been found to be discarded but whose <code>finalize</code>
1725 * methods have not yet been run. When control returns from the
1726 * method call, the Java Virtual Machine has made a best effort to
1727 * complete all outstanding finalizations.
1728 * <p>
1729 * The call <code>System.runFinalization()</code> is effectively
1730 * equivalent to the call:
1731 * <blockquote><pre>
1732 * Runtime.getRuntime().runFinalization()
1733 * </pre></blockquote>
1734 *
1735 * @see java.lang.Runtime#runFinalization()
1736 */
1737 public static void runFinalization() {
1738 Runtime.getRuntime().runFinalization();
1739 }
1740
1741 /**
1742 * Enable or disable finalization on exit; doing so specifies that the
1743 * finalizers of all objects that have finalizers that have not yet been
1744 * automatically invoked are to be run before the Java runtime exits.
1745 * By default, finalization on exit is disabled.
1746 *
1747 * <p>If there is a security manager,
1748 * its <code>checkExit</code> method is first called
1749 * with 0 as its argument to ensure the exit is allowed.
1750 * This could result in a SecurityException.
1751 *
1752 * @deprecated This method is inherently unsafe. It may result in
1753 * finalizers being called on live objects while other threads are
1754 * concurrently manipulating those objects, resulting in erratic
1755 * behavior or deadlock.
1756 * This method is subject to removal in a future version of Java SE.
1757 * @param value indicating enabling or disabling of finalization
1758 * @throws SecurityException
1759 * if a security manager exists and its <code>checkExit</code>
1760 * method doesn't allow the exit.
1761 *
1762 * @see java.lang.Runtime#exit(int)
1763 * @see java.lang.Runtime#gc()
1764 * @see java.lang.SecurityManager#checkExit(int)
1765 * @since 1.1
1766 */
1767 @Deprecated(since="1.2", forRemoval=true)
1768 @SuppressWarnings("removal")
1769 public static void runFinalizersOnExit(boolean value) {
1770 Runtime.runFinalizersOnExit(value);
1771 }
1772
1773 /**
1774 * Loads the native library specified by the filename argument. The filename
1775 * argument must be an absolute path name.
1776 *
1777 * If the filename argument, when stripped of any platform-specific library
1778 * prefix, path, and file extension, indicates a library whose name is,
1779 * for example, L, and a native library called L is statically linked
1780 * with the VM, then the JNI_OnLoad_L function exported by the library
1781 * is invoked rather than attempting to load a dynamic library.
1782 * A filename matching the argument does not have to exist in the
1783 * file system.
1784 * See the JNI Specification for more details.
1785 *
1786 * Otherwise, the filename argument is mapped to a native library image in
1787 * an implementation-dependent manner.
1788 *
1789 * <p>
1790 * The call <code>System.load(name)</code> is effectively equivalent
1791 * to the call:
1792 * <blockquote><pre>
1793 * Runtime.getRuntime().load(name)
1794 * </pre></blockquote>
1795 *
1796 * @param filename the file to load.
1797 * @exception SecurityException if a security manager exists and its
1798 * <code>checkLink</code> method doesn't allow
1799 * loading of the specified dynamic library
1800 * @exception UnsatisfiedLinkError if either the filename is not an
1801 * absolute path name, the native library is not statically
1802 * linked with the VM, or the library cannot be mapped to
1803 * a native library image by the host system.
1804 * @exception NullPointerException if <code>filename</code> is
1805 * <code>null</code>
1806 * @see java.lang.Runtime#load(java.lang.String)
1807 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1808 */
1809 @CallerSensitive
1810 public static void load(String filename) {
1811 Runtime.getRuntime().load0(Reflection.getCallerClass(), filename);
1812 }
1813
1814 /**
1815 * Loads the native library specified by the <code>libname</code>
1816 * argument. The <code>libname</code> argument must not contain any platform
1817 * specific prefix, file extension or path. If a native library
1818 * called <code>libname</code> is statically linked with the VM, then the
1819 * JNI_OnLoad_<code>libname</code> function exported by the library is invoked.
1820 * See the JNI Specification for more details.
1821 *
1822 * Otherwise, the libname argument is loaded from a system library
1823 * location and mapped to a native library image in an implementation-
1824 * dependent manner.
1825 * <p>
1826 * The call <code>System.loadLibrary(name)</code> is effectively
1827 * equivalent to the call
1828 * <blockquote><pre>
1829 * Runtime.getRuntime().loadLibrary(name)
1830 * </pre></blockquote>
1831 *
1832 * @param libname the name of the library.
1833 * @exception SecurityException if a security manager exists and its
1834 * <code>checkLink</code> method doesn't allow
1835 * loading of the specified dynamic library
1836 * @exception UnsatisfiedLinkError if either the libname argument
1837 * contains a file path, the native library is not statically
1838 * linked with the VM, or the library cannot be mapped to a
1839 * native library image by the host system.
1840 * @exception NullPointerException if <code>libname</code> is
1841 * <code>null</code>
1842 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1843 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1844 */
1845 @CallerSensitive
1846 public static void loadLibrary(String libname) {
1847 Runtime.getRuntime().loadLibrary0(Reflection.getCallerClass(), libname);
1848 }
1849
1850 /**
1851 * Maps a library name into a platform-specific string representing
1852 * a native library.
1853 *
1854 * @param libname the name of the library.
1855 * @return a platform-dependent native library name.
1856 * @exception NullPointerException if <code>libname</code> is
1857 * <code>null</code>
1858 * @see java.lang.System#loadLibrary(java.lang.String)
1859 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1860 * @since 1.2
1861 */
1862 public static native String mapLibraryName(String libname);
1863
1864 /**
1865 * Create PrintStream for stdout/err based on encoding.
1866 */
1867 private static PrintStream newPrintStream(FileOutputStream fos, String enc) {
1868 if (enc != null) {
1869 try {
1870 return new PrintStream(new BufferedOutputStream(fos, 128), true, enc);
1871 } catch (UnsupportedEncodingException uee) {}
1872 }
1873 return new PrintStream(new BufferedOutputStream(fos, 128), true);
1874 }
1875
1876 /**
1877 * Logs an exception/error at initialization time to stdout or stderr.
1878 *
1879 * @param printToStderr to print to stderr rather than stdout
1880 * @param printStackTrace to print the stack trace
1881 * @param msg the message to print before the exception, can be {@code null}
1882 * @param e the exception or error
1883 */
1884 private static void logInitException(boolean printToStderr,
1885 boolean printStackTrace,
1886 String msg,
1887 Throwable e) {
1888 if (VM.initLevel() < 1) {
1889 throw new InternalError("system classes not initialized");
1890 }
1891 PrintStream log = (printToStderr) ? err : out;
1892 if (msg != null) {
1893 log.println(msg);
1894 }
1895 if (printStackTrace) {
1896 e.printStackTrace(log);
1897 } else {
1898 log.println(e);
1899 for (Throwable suppressed : e.getSuppressed()) {
1900 log.println("Suppressed: " + suppressed);
1901 }
1902 Throwable cause = e.getCause();
1903 if (cause != null) {
1904 log.println("Caused by: " + cause);
1905 }
1906 }
1907 }
1908
1909 /**
1910 * Initialize the system class. Called after thread initialization.
1911 */
1912 private static void initPhase1() {
1913
1914 // VM might invoke JNU_NewStringPlatform() to set those encoding
1915 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1916 // during "props" initialization, in which it may need access, via
1917 // System.getProperty(), to the related system encoding property that
1918 // have been initialized (put into "props") at early stage of the
1919 // initialization. So make sure the "props" is available at the
1920 // very beginning of the initialization and all system properties to
1921 // be put into it directly.
1922 props = new Properties();
1923 initProperties(props); // initialized by the VM
1924
1925 // There are certain system configurations that may be controlled by
1926 // VM options such as the maximum amount of direct memory and
1927 // Integer cache size used to support the object identity semantics
1928 // of autoboxing. Typically, the library will obtain these values
1929 // from the properties set by the VM. If the properties are for
1930 // internal implementation use only, these properties should be
1931 // removed from the system properties.
1932 //
1933 // See java.lang.Integer.IntegerCache and the
1934 // VM.saveAndRemoveProperties method for example.
1935 //
1936 // Save a private copy of the system properties object that
1937 // can only be accessed by the internal implementation. Remove
1938 // certain system properties that are not intended for public access.
1939 VM.saveAndRemoveProperties(props);
1940
1941 lineSeparator = props.getProperty("line.separator");
1942 VersionProps.init();
1943
1944 FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
1945 FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
1946 FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
1947 setIn0(new BufferedInputStream(fdIn));
1948 setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
1949 setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
1950
1951 // Load the zip library now in order to keep java.util.zip.ZipFile
1952 // from trying to use itself to load this library later.
1953 loadLibrary("zip");
1954
1955 // Setup Java signal handlers for HUP, TERM, and INT (where available).
1956 Terminator.setup();
1957
1958 // Initialize any miscellaneous operating system settings that need to be
1959 // set for the class libraries. Currently this is no-op everywhere except
1960 // for Windows where the process-wide error mode is set before the java.io
1961 // classes are used.
1962 VM.initializeOSEnvironment();
1963
1964 // The main thread is not added to its thread group in the same
1965 // way as other threads; we must do it ourselves here.
1966 Thread current = Thread.currentThread();
1967 current.getThreadGroup().add(current);
1968
1969 // register shared secrets
1970 setJavaLangAccess();
1971
1972 // Subsystems that are invoked during initialization can invoke
1973 // VM.isBooted() in order to avoid doing things that should
1974 // wait until the VM is fully initialized. The initialization level
1975 // is incremented from 0 to 1 here to indicate the first phase of
1976 // initialization has completed.
1977 // IMPORTANT: Ensure that this remains the last initialization action!
1978 VM.initLevel(1);
1979 }
1980
1981 // @see #initPhase2()
1982 static ModuleLayer bootLayer;
1983
1984 /*
1985 * Invoked by VM. Phase 2 module system initialization.
1986 * Only classes in java.base can be loaded in this phase.
1987 *
1988 * @param printToStderr print exceptions to stderr rather than stdout
1989 * @param printStackTrace print stack trace when exception occurs
1990 *
1991 * @return JNI_OK for success, JNI_ERR for failure
1992 */
1993 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
1994 try {
1995 bootLayer = ModuleBootstrap.boot();
1996 } catch (Exception | Error e) {
1997 logInitException(printToStderr, printStackTrace,
1998 "Error occurred during initialization of boot layer", e);
1999 return -1; // JNI_ERR
2000 }
2001
2002 // module system initialized
2003 VM.initLevel(2);
2004
2005 return 0; // JNI_OK
2006 }
2007
2008 /*
2009 * Invoked by VM. Phase 3 is the final system initialization:
2010 * 1. set security manager
2011 * 2. set system class loader
2012 * 3. set TCCL
2013 *
2014 * This method must be called after the module system initialization.
2015 * The security manager and system class loader may be custom class from
2016 * the application classpath or modulepath.
2017 */
2018 private static void initPhase3() {
2019 // set security manager
2020 String cn = System.getProperty("java.security.manager");
2021 if (cn != null) {
2022 if (cn.isEmpty() || "default".equals(cn)) {
2023 System.setSecurityManager(new SecurityManager());
2024 } else {
2025 try {
2026 Class<?> c = Class.forName(cn, false, ClassLoader.getBuiltinAppClassLoader());
2027 Constructor<?> ctor = c.getConstructor();
2028 // Must be a public subclass of SecurityManager with
2029 // a public no-arg constructor
2030 if (!SecurityManager.class.isAssignableFrom(c) ||
2031 !Modifier.isPublic(c.getModifiers()) ||
2032 !Modifier.isPublic(ctor.getModifiers())) {
2033 throw new Error("Could not create SecurityManager: " + ctor.toString());
2034 }
2035 // custom security manager implementation may be in unnamed module
2036 // or a named module but non-exported package
2037 ctor.setAccessible(true);
2038 SecurityManager sm = (SecurityManager) ctor.newInstance();
2039 System.setSecurityManager(sm);
2040 } catch (Exception e) {
2041 throw new Error("Could not create SecurityManager", e);
2042 }
2043 }
2044 }
2045
2046 // initializing the system class loader
2047 VM.initLevel(3);
2048
2049 // system class loader initialized
2050 ClassLoader scl = ClassLoader.initSystemClassLoader();
2051
2052 // set TCCL
2053 Thread.currentThread().setContextClassLoader(scl);
2054
2055 // system is fully initialized
2056 VM.initLevel(4);
2057 }
2058
2059 private static void setJavaLangAccess() {
2060 // Allow privileged classes outside of java.lang
2061 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2062 public Method getMethodOrNull(Class<?> klass, String name, Class<?>... parameterTypes) {
2063 return klass.getMethodOrNull(name, parameterTypes);
2064 }
2065 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2066 return klass.getConstantPool();
2067 }
2068 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2069 return klass.casAnnotationType(oldType, newType);
2070 }
2071 public AnnotationType getAnnotationType(Class<?> klass) {
2072 return klass.getAnnotationType();
2073 }
2074 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2075 return klass.getDeclaredAnnotationMap();
2076 }
2077 public byte[] getRawClassAnnotations(Class<?> klass) {
2078 return klass.getRawAnnotations();
2079 }
2080 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2081 return klass.getRawTypeAnnotations();
2082 }
2083 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2084 return Class.getExecutableTypeAnnotationBytes(executable);
2085 }
2086 public <E extends Enum<E>>
2087 E[] getEnumConstantsShared(Class<E> klass) {
2088 return klass.getEnumConstantsShared();
2089 }
2090 public void blockedOn(Thread t, Interruptible b) {
2091 t.blockedOn(b);
2092 }
2093 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2094 Shutdown.add(slot, registerShutdownInProgress, hook);
2095 }
2096 public String newStringUnsafe(char[] chars) {
2097 return new String(chars, true);
2098 }
2099 public Thread newThreadWithAcc(Runnable target, AccessControlContext acc) {
2100 return new Thread(target, acc);
2101 }
2102 @SuppressWarnings("deprecation")
2103 public void invokeFinalize(Object o) throws Throwable {
2104 o.finalize();
2105 }
2106 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2107 return cl.createOrGetClassLoaderValueMap();
2108 }
2109 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2110 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2111 }
2112 public Class<?> findBootstrapClassOrNull(ClassLoader cl, String name) {
2113 return cl.findBootstrapClassOrNull(name);
2114 }
2115 public Stream<Package> packages(ClassLoader cl) {
2116 return cl.packages();
2117 }
2118 public Package definePackage(ClassLoader cl, String name, Module module) {
2119 return cl.definePackage(name, module);
2120 }
2121 public String fastUUID(long lsb, long msb) {
2122 return Long.fastUUID(lsb, msb);
2123 }
2124 public void addNonExportedPackages(ModuleLayer layer) {
2125 SecurityManager.addNonExportedPackages(layer);
2126 }
2127 public void invalidatePackageAccessCache() {
2128 SecurityManager.invalidatePackageAccessCache();
2129 }
2130 public Module defineModule(ClassLoader loader,
2131 ModuleDescriptor descriptor,
2132 URI uri) {
2133 return new Module(null, loader, descriptor, uri);
2134 }
2135 public Module defineUnnamedModule(ClassLoader loader) {
2136 return new Module(loader);
2137 }
2138 public void addReads(Module m1, Module m2) {
2139 m1.implAddReads(m2);
2140 }
2141 public void addReadsAllUnnamed(Module m) {
2142 m.implAddReadsAllUnnamed();
2143 }
2144 public void addExports(Module m, String pn, Module other) {
2145 m.implAddExports(pn, other);
2146 }
2147 public void addExportsToAllUnnamed(Module m, String pn) {
2148 m.implAddExportsToAllUnnamed(pn);
2149 }
2150 public void addOpens(Module m, String pn, Module other) {
2151 m.implAddOpens(pn, other);
2152 }
2153 public void addOpensToAllUnnamed(Module m, String pn) {
2154 m.implAddOpensToAllUnnamed(pn);
2155 }
2156 public void addUses(Module m, Class<?> service) {
2157 m.implAddUses(service);
2158 }
2159 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2160 return layer.getServicesCatalog();
2161 }
2162 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2163 return layer.layers();
2164 }
2165 public Stream<ModuleLayer> layers(ClassLoader loader) {
2166 return ModuleLayer.layers(loader);
2167 }
2168 public Class<?> loadValueTypeClass(Module module, ClassLoader cl, String name) {
2169 try {
2170 // VM support to define DVT
2171 Class<?> c = Class.forName0(name, false, cl, Object.class);
2172 // catch if the given name is not the name of a DVT class
2173 if (!c.isValueClass()) {
2174 throw new InternalError(c.getName() + " not a value type");
2175 }
2176 return c;
2177 } catch (ClassNotFoundException e) {
2178 throw new InternalError(e);
2179 }
2180 }
2181 });
2182 }
2183 }