1 /*
2 * Copyright (c) 1994, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package java.lang;
26
27 import java.io.BufferedInputStream;
28 import java.io.BufferedOutputStream;
29 import java.io.Console;
30 import java.io.FileDescriptor;
31 import java.io.FileInputStream;
32 import java.io.FileOutputStream;
33 import java.io.IOException;
34 import java.io.InputStream;
35 import java.io.PrintStream;
36 import java.io.UnsupportedEncodingException;
37 import java.lang.annotation.Annotation;
38 import java.lang.module.ModuleDescriptor;
39 import java.lang.reflect.Constructor;
40 import java.lang.reflect.Executable;
41 import java.lang.reflect.Method;
42 import java.lang.reflect.Modifier;
43 import java.net.URI;
44 import java.net.URL;
45 import java.security.AccessControlContext;
46 import java.security.ProtectionDomain;
47 import java.security.AccessController;
48 import java.security.PrivilegedAction;
49 import java.nio.channels.Channel;
50 import java.nio.channels.spi.SelectorProvider;
51 import java.util.Map;
52 import java.util.Objects;
53 import java.util.Properties;
54 import java.util.PropertyPermission;
55 import java.util.ResourceBundle;
56 import java.util.function.Supplier;
57 import java.util.concurrent.ConcurrentHashMap;
58 import java.util.stream.Stream;
59
60 import jdk.internal.module.ModuleBootstrap;
61 import jdk.internal.module.ServicesCatalog;
62 import jdk.internal.reflect.CallerSensitive;
63 import jdk.internal.reflect.Reflection;
64 import jdk.internal.HotSpotIntrinsicCandidate;
65 import jdk.internal.misc.JavaLangAccess;;
66 import jdk.internal.misc.SharedSecrets;;
67 import jdk.internal.misc.VM;
68 import jdk.internal.logger.LoggerFinderLoader;
69 import jdk.internal.logger.LazyLoggers;
70 import jdk.internal.logger.LocalizedLoggerWrapper;
71 import sun.reflect.annotation.AnnotationType;
72 import sun.nio.ch.Interruptible;
73 import sun.security.util.SecurityConstants;
74
75 /**
76 * The <code>System</code> class contains several useful class fields
77 * and methods. It cannot be instantiated.
78 *
79 * <p>Among the facilities provided by the <code>System</code> class
80 * are standard input, standard output, and error output streams;
81 * access to externally defined properties and environment
82 * variables; a means of loading files and libraries; and a utility
83 * method for quickly copying a portion of an array.
84 *
85 * @author unascribed
86 * @since 1.0
87 */
88 public final class System {
89 /* register the natives via the static initializer.
90 *
91 * VM will invoke the initializeSystemClass method to complete
92 * the initialization for this class separated from clinit.
93 * Note that to use properties set by the VM, see the constraints
94 * described in the initializeSystemClass method.
95 */
96 private static native void registerNatives();
97 static {
98 registerNatives();
99 }
100
101 /** Don't let anyone instantiate this class */
102 private System() {
103 }
104
105 /**
106 * The "standard" input stream. This stream is already
107 * open and ready to supply input data. Typically this stream
108 * corresponds to keyboard input or another input source specified by
109 * the host environment or user.
110 */
111 public static final InputStream in = null;
112
113 /**
114 * The "standard" output stream. This stream is already
115 * open and ready to accept output data. Typically this stream
116 * corresponds to display output or another output destination
117 * specified by the host environment or user.
118 * <p>
119 * For simple stand-alone Java applications, a typical way to write
120 * a line of output data is:
121 * <blockquote><pre>
122 * System.out.println(data)
123 * </pre></blockquote>
124 * <p>
125 * See the <code>println</code> methods in class <code>PrintStream</code>.
126 *
127 * @see java.io.PrintStream#println()
128 * @see java.io.PrintStream#println(boolean)
129 * @see java.io.PrintStream#println(char)
130 * @see java.io.PrintStream#println(char[])
131 * @see java.io.PrintStream#println(double)
132 * @see java.io.PrintStream#println(float)
133 * @see java.io.PrintStream#println(int)
134 * @see java.io.PrintStream#println(long)
135 * @see java.io.PrintStream#println(java.lang.Object)
136 * @see java.io.PrintStream#println(java.lang.String)
137 */
138 public static final PrintStream out = null;
139
140 /**
141 * The "standard" error output stream. This stream is already
142 * open and ready to accept output data.
143 * <p>
144 * Typically this stream corresponds to display output or another
145 * output destination specified by the host environment or user. By
146 * convention, this output stream is used to display error messages
147 * or other information that should come to the immediate attention
148 * of a user even if the principal output stream, the value of the
149 * variable <code>out</code>, has been redirected to a file or other
150 * destination that is typically not continuously monitored.
151 */
152 public static final PrintStream err = null;
153
154 /* The security manager for the system.
155 */
156 private static volatile SecurityManager security;
157
158 /**
159 * Reassigns the "standard" input stream.
160 *
161 * <p>First, if there is a security manager, its <code>checkPermission</code>
162 * method is called with a <code>RuntimePermission("setIO")</code> permission
163 * to see if it's ok to reassign the "standard" input stream.
164 *
165 * @param in the new standard input stream.
166 *
167 * @throws SecurityException
168 * if a security manager exists and its
169 * <code>checkPermission</code> method doesn't allow
170 * reassigning of the standard input stream.
171 *
172 * @see SecurityManager#checkPermission
173 * @see java.lang.RuntimePermission
174 *
175 * @since 1.1
176 */
177 public static void setIn(InputStream in) {
178 checkIO();
179 setIn0(in);
180 }
181
182 /**
183 * Reassigns the "standard" output stream.
184 *
185 * <p>First, if there is a security manager, its <code>checkPermission</code>
186 * method is called with a <code>RuntimePermission("setIO")</code> permission
187 * to see if it's ok to reassign the "standard" output stream.
188 *
189 * @param out the new standard output stream
190 *
191 * @throws SecurityException
192 * if a security manager exists and its
193 * <code>checkPermission</code> method doesn't allow
194 * reassigning of the standard output stream.
195 *
196 * @see SecurityManager#checkPermission
197 * @see java.lang.RuntimePermission
198 *
199 * @since 1.1
200 */
201 public static void setOut(PrintStream out) {
202 checkIO();
203 setOut0(out);
204 }
205
206 /**
207 * Reassigns the "standard" error output stream.
208 *
209 * <p>First, if there is a security manager, its <code>checkPermission</code>
210 * method is called with a <code>RuntimePermission("setIO")</code> permission
211 * to see if it's ok to reassign the "standard" error output stream.
212 *
213 * @param err the new standard error output stream.
214 *
215 * @throws SecurityException
216 * if a security manager exists and its
217 * <code>checkPermission</code> method doesn't allow
218 * reassigning of the standard error output stream.
219 *
220 * @see SecurityManager#checkPermission
221 * @see java.lang.RuntimePermission
222 *
223 * @since 1.1
224 */
225 public static void setErr(PrintStream err) {
226 checkIO();
227 setErr0(err);
228 }
229
230 private static volatile Console cons;
231 /**
232 * Returns the unique {@link java.io.Console Console} object associated
233 * with the current Java virtual machine, if any.
234 *
235 * @return The system console, if any, otherwise {@code null}.
236 *
237 * @since 1.6
238 */
239 public static Console console() {
240 Console c;
241 if ((c = cons) == null) {
242 synchronized (System.class) {
243 if ((c = cons) == null) {
244 cons = c = SharedSecrets.getJavaIOAccess().console();
245 }
246 }
247 }
248 return c;
249 }
250
251 /**
252 * Returns the channel inherited from the entity that created this
253 * Java virtual machine.
254 *
255 * <p> This method returns the channel obtained by invoking the
256 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
257 * inheritedChannel} method of the system-wide default
258 * {@link java.nio.channels.spi.SelectorProvider} object. </p>
259 *
260 * <p> In addition to the network-oriented channels described in
261 * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
262 * inheritedChannel}, this method may return other kinds of
263 * channels in the future.
264 *
265 * @return The inherited channel, if any, otherwise {@code null}.
266 *
267 * @throws IOException
268 * If an I/O error occurs
269 *
270 * @throws SecurityException
271 * If a security manager is present and it does not
272 * permit access to the channel.
273 *
274 * @since 1.5
275 */
276 public static Channel inheritedChannel() throws IOException {
277 return SelectorProvider.provider().inheritedChannel();
278 }
279
280 private static void checkIO() {
281 SecurityManager sm = getSecurityManager();
282 if (sm != null) {
283 sm.checkPermission(new RuntimePermission("setIO"));
284 }
285 }
286
287 private static native void setIn0(InputStream in);
288 private static native void setOut0(PrintStream out);
289 private static native void setErr0(PrintStream err);
290
291 /**
292 * Sets the System security.
293 *
294 * <p> If there is a security manager already installed, this method first
295 * calls the security manager's <code>checkPermission</code> method
296 * with a <code>RuntimePermission("setSecurityManager")</code>
297 * permission to ensure it's ok to replace the existing
298 * security manager.
299 * This may result in throwing a <code>SecurityException</code>.
300 *
301 * <p> Otherwise, the argument is established as the current
302 * security manager. If the argument is <code>null</code> and no
303 * security manager has been established, then no action is taken and
304 * the method simply returns.
305 *
306 * @param s the security manager.
307 * @exception SecurityException if the security manager has already
308 * been set and its <code>checkPermission</code> method
309 * doesn't allow it to be replaced.
310 * @see #getSecurityManager
311 * @see SecurityManager#checkPermission
312 * @see java.lang.RuntimePermission
313 */
314 public static void setSecurityManager(final SecurityManager s) {
315 if (s != null) {
316 try {
317 s.checkPackageAccess("java.lang");
318 } catch (Exception e) {
319 // no-op
320 }
321 }
322 setSecurityManager0(s);
323 }
324
325 private static synchronized
326 void setSecurityManager0(final SecurityManager s) {
327 SecurityManager sm = getSecurityManager();
328 if (sm != null) {
329 // ask the currently installed security manager if we
330 // can replace it.
331 sm.checkPermission(new RuntimePermission
332 ("setSecurityManager"));
333 }
334
335 if ((s != null) && (s.getClass().getClassLoader() != null)) {
336 // New security manager class is not on bootstrap classpath.
337 // Cause policy to get initialized before we install the new
338 // security manager, in order to prevent infinite loops when
339 // trying to initialize the policy (which usually involves
340 // accessing some security and/or system properties, which in turn
341 // calls the installed security manager's checkPermission method
342 // which will loop infinitely if there is a non-system class
343 // (in this case: the new security manager class) on the stack).
344 AccessController.doPrivileged(new PrivilegedAction<>() {
345 public Object run() {
346 s.getClass().getProtectionDomain().implies
347 (SecurityConstants.ALL_PERMISSION);
348 return null;
349 }
350 });
351 }
352
353 security = s;
354 }
355
356 /**
357 * Gets the system security interface.
358 *
359 * @return if a security manager has already been established for the
360 * current application, then that security manager is returned;
361 * otherwise, <code>null</code> is returned.
362 * @see #setSecurityManager
363 */
364 public static SecurityManager getSecurityManager() {
365 return security;
366 }
367
368 /**
369 * Returns the current time in milliseconds. Note that
370 * while the unit of time of the return value is a millisecond,
371 * the granularity of the value depends on the underlying
372 * operating system and may be larger. For example, many
373 * operating systems measure time in units of tens of
374 * milliseconds.
375 *
376 * <p> See the description of the class <code>Date</code> for
377 * a discussion of slight discrepancies that may arise between
378 * "computer time" and coordinated universal time (UTC).
379 *
380 * @return the difference, measured in milliseconds, between
381 * the current time and midnight, January 1, 1970 UTC.
382 * @see java.util.Date
383 */
384 @HotSpotIntrinsicCandidate
385 public static native long currentTimeMillis();
386
387 /**
388 * Returns the current value of the running Java Virtual Machine's
389 * high-resolution time source, in nanoseconds.
390 *
391 * <p>This method can only be used to measure elapsed time and is
392 * not related to any other notion of system or wall-clock time.
393 * The value returned represents nanoseconds since some fixed but
394 * arbitrary <i>origin</i> time (perhaps in the future, so values
395 * may be negative). The same origin is used by all invocations of
396 * this method in an instance of a Java virtual machine; other
397 * virtual machine instances are likely to use a different origin.
398 *
399 * <p>This method provides nanosecond precision, but not necessarily
400 * nanosecond resolution (that is, how frequently the value changes)
401 * - no guarantees are made except that the resolution is at least as
402 * good as that of {@link #currentTimeMillis()}.
403 *
404 * <p>Differences in successive calls that span greater than
405 * approximately 292 years (2<sup>63</sup> nanoseconds) will not
406 * correctly compute elapsed time due to numerical overflow.
407 *
408 * <p>The values returned by this method become meaningful only when
409 * the difference between two such values, obtained within the same
410 * instance of a Java virtual machine, is computed.
411 *
412 * <p>For example, to measure how long some code takes to execute:
413 * <pre> {@code
414 * long startTime = System.nanoTime();
415 * // ... the code being measured ...
416 * long elapsedNanos = System.nanoTime() - startTime;}</pre>
417 *
418 * <p>To compare elapsed time against a timeout, use <pre> {@code
419 * if (System.nanoTime() - startTime >= timeoutNanos) ...}</pre>
420 * instead of <pre> {@code
421 * if (System.nanoTime() >= startTime + timeoutNanos) ...}</pre>
422 * because of the possibility of numerical overflow.
423 *
424 * @return the current value of the running Java Virtual Machine's
425 * high-resolution time source, in nanoseconds
426 * @since 1.5
427 */
428 @HotSpotIntrinsicCandidate
429 public static native long nanoTime();
430
431 /**
432 * Copies an array from the specified source array, beginning at the
433 * specified position, to the specified position of the destination array.
434 * A subsequence of array components are copied from the source
435 * array referenced by <code>src</code> to the destination array
436 * referenced by <code>dest</code>. The number of components copied is
437 * equal to the <code>length</code> argument. The components at
438 * positions <code>srcPos</code> through
439 * <code>srcPos+length-1</code> in the source array are copied into
440 * positions <code>destPos</code> through
441 * <code>destPos+length-1</code>, respectively, of the destination
442 * array.
443 * <p>
444 * If the <code>src</code> and <code>dest</code> arguments refer to the
445 * same array object, then the copying is performed as if the
446 * components at positions <code>srcPos</code> through
447 * <code>srcPos+length-1</code> were first copied to a temporary
448 * array with <code>length</code> components and then the contents of
449 * the temporary array were copied into positions
450 * <code>destPos</code> through <code>destPos+length-1</code> of the
451 * destination array.
452 * <p>
453 * If <code>dest</code> is <code>null</code>, then a
454 * <code>NullPointerException</code> is thrown.
455 * <p>
456 * If <code>src</code> is <code>null</code>, then a
457 * <code>NullPointerException</code> is thrown and the destination
458 * array is not modified.
459 * <p>
460 * Otherwise, if any of the following is true, an
461 * <code>ArrayStoreException</code> is thrown and the destination is
462 * not modified:
463 * <ul>
464 * <li>The <code>src</code> argument refers to an object that is not an
465 * array.
466 * <li>The <code>dest</code> argument refers to an object that is not an
467 * array.
468 * <li>The <code>src</code> argument and <code>dest</code> argument refer
469 * to arrays whose component types are different primitive types.
470 * <li>The <code>src</code> argument refers to an array with a primitive
471 * component type and the <code>dest</code> argument refers to an array
472 * with a reference component type.
473 * <li>The <code>src</code> argument refers to an array with a reference
474 * component type and the <code>dest</code> argument refers to an array
475 * with a primitive component type.
476 * </ul>
477 * <p>
478 * Otherwise, if any of the following is true, an
479 * <code>IndexOutOfBoundsException</code> is
480 * thrown and the destination is not modified:
481 * <ul>
482 * <li>The <code>srcPos</code> argument is negative.
483 * <li>The <code>destPos</code> argument is negative.
484 * <li>The <code>length</code> argument is negative.
485 * <li><code>srcPos+length</code> is greater than
486 * <code>src.length</code>, the length of the source array.
487 * <li><code>destPos+length</code> is greater than
488 * <code>dest.length</code>, the length of the destination array.
489 * </ul>
490 * <p>
491 * Otherwise, if any actual component of the source array from
492 * position <code>srcPos</code> through
493 * <code>srcPos+length-1</code> cannot be converted to the component
494 * type of the destination array by assignment conversion, an
495 * <code>ArrayStoreException</code> is thrown. In this case, let
496 * <b><i>k</i></b> be the smallest nonnegative integer less than
497 * length such that <code>src[srcPos+</code><i>k</i><code>]</code>
498 * cannot be converted to the component type of the destination
499 * array; when the exception is thrown, source array components from
500 * positions <code>srcPos</code> through
501 * <code>srcPos+</code><i>k</i><code>-1</code>
502 * will already have been copied to destination array positions
503 * <code>destPos</code> through
504 * <code>destPos+</code><i>k</I><code>-1</code> and no other
505 * positions of the destination array will have been modified.
506 * (Because of the restrictions already itemized, this
507 * paragraph effectively applies only to the situation where both
508 * arrays have component types that are reference types.)
509 *
510 * @param src the source array.
511 * @param srcPos starting position in the source array.
512 * @param dest the destination array.
513 * @param destPos starting position in the destination data.
514 * @param length the number of array elements to be copied.
515 * @exception IndexOutOfBoundsException if copying would cause
516 * access of data outside array bounds.
517 * @exception ArrayStoreException if an element in the <code>src</code>
518 * array could not be stored into the <code>dest</code> array
519 * because of a type mismatch.
520 * @exception NullPointerException if either <code>src</code> or
521 * <code>dest</code> is <code>null</code>.
522 */
523 @HotSpotIntrinsicCandidate
524 public static native void arraycopy(Object src, int srcPos,
525 Object dest, int destPos,
526 int length);
527
528 /**
529 * Returns the same hash code for the given object as
530 * would be returned by the default method hashCode(),
531 * whether or not the given object's class overrides
532 * hashCode().
533 * The hash code for the null reference is zero.
534 *
535 * @param x object for which the hashCode is to be calculated
536 * @return the hashCode
537 * @since 1.1
538 */
539 @HotSpotIntrinsicCandidate
540 public static native int identityHashCode(Object x);
541
542 /**
543 * System properties. The following properties are guaranteed to be defined:
544 * <dl>
545 * <dt>java.version <dd>Java version number
546 * <dt>java.vendor <dd>Java vendor specific string
547 * <dt>java.vendor.url <dd>Java vendor URL
548 * <dt>java.home <dd>Java installation directory
549 * <dt>java.class.version <dd>Java class version number
550 * <dt>java.class.path <dd>Java classpath
551 * <dt>os.name <dd>Operating System Name
552 * <dt>os.arch <dd>Operating System Architecture
553 * <dt>os.version <dd>Operating System Version
554 * <dt>file.separator <dd>File separator ("/" on Unix)
555 * <dt>path.separator <dd>Path separator (":" on Unix)
556 * <dt>line.separator <dd>Line separator ("\n" on Unix)
557 * <dt>user.name <dd>User account name
558 * <dt>user.home <dd>User home directory
559 * <dt>user.dir <dd>User's current working directory
560 * </dl>
561 */
562
563 private static Properties props;
564 private static native Properties initProperties(Properties props);
565
566 /**
567 * Determines the current system properties.
568 * <p>
569 * First, if there is a security manager, its
570 * <code>checkPropertiesAccess</code> method is called with no
571 * arguments. This may result in a security exception.
572 * <p>
573 * The current set of system properties for use by the
574 * {@link #getProperty(String)} method is returned as a
575 * <code>Properties</code> object. If there is no current set of
576 * system properties, a set of system properties is first created and
577 * initialized. This set of system properties always includes values
578 * for the following keys:
579 * <table summary="Shows property keys and associated values">
580 * <tr><th>Key</th>
581 * <th>Description of Associated Value</th></tr>
582 * <tr><td><code>java.version</code></td>
583 * <td>Java Runtime Environment version which may be interpreted
584 * as a {@link Runtime.Version}</td></tr>
585 * <tr><td><code>java.vendor</code></td>
586 * <td>Java Runtime Environment vendor</td></tr>
587 * <tr><td><code>java.vendor.url</code></td>
588 * <td>Java vendor URL</td></tr>
589 * <tr><td><code>java.home</code></td>
590 * <td>Java installation directory</td></tr>
591 * <tr><td><code>java.vm.specification.version</code></td>
592 * <td>Java Virtual Machine specification version which may be
593 * interpreted as a {@link Runtime.Version}</td></tr>
594 * <tr><td><code>java.vm.specification.vendor</code></td>
595 * <td>Java Virtual Machine specification vendor</td></tr>
596 * <tr><td><code>java.vm.specification.name</code></td>
597 * <td>Java Virtual Machine specification name</td></tr>
598 * <tr><td><code>java.vm.version</code></td>
599 * <td>Java Virtual Machine implementation version which may be
600 * interpreted as a {@link Runtime.Version}</td></tr>
601 * <tr><td><code>java.vm.vendor</code></td>
602 * <td>Java Virtual Machine implementation vendor</td></tr>
603 * <tr><td><code>java.vm.name</code></td>
604 * <td>Java Virtual Machine implementation name</td></tr>
605 * <tr><td><code>java.specification.version</code></td>
606 * <td>Java Runtime Environment specification version which may be
607 * interpreted as a {@link Runtime.Version}</td></tr>
608 * <tr><td><code>java.specification.vendor</code></td>
609 * <td>Java Runtime Environment specification vendor</td></tr>
610 * <tr><td><code>java.specification.name</code></td>
611 * <td>Java Runtime Environment specification name</td></tr>
612 * <tr><td><code>java.class.version</code></td>
613 * <td>Java class format version number</td></tr>
614 * <tr><td><code>java.class.path</code></td>
615 * <td>Java class path</td></tr>
616 * <tr><td><code>java.library.path</code></td>
617 * <td>List of paths to search when loading libraries</td></tr>
618 * <tr><td><code>java.io.tmpdir</code></td>
619 * <td>Default temp file path</td></tr>
620 * <tr><td><code>java.compiler</code></td>
621 * <td>Name of JIT compiler to use</td></tr>
622 * <tr><td><code>os.name</code></td>
623 * <td>Operating system name</td></tr>
624 * <tr><td><code>os.arch</code></td>
625 * <td>Operating system architecture</td></tr>
626 * <tr><td><code>os.version</code></td>
627 * <td>Operating system version</td></tr>
628 * <tr><td><code>file.separator</code></td>
629 * <td>File separator ("/" on UNIX)</td></tr>
630 * <tr><td><code>path.separator</code></td>
631 * <td>Path separator (":" on UNIX)</td></tr>
632 * <tr><td><code>line.separator</code></td>
633 * <td>Line separator ("\n" on UNIX)</td></tr>
634 * <tr><td><code>user.name</code></td>
635 * <td>User's account name</td></tr>
636 * <tr><td><code>user.home</code></td>
637 * <td>User's home directory</td></tr>
638 * <tr><td><code>user.dir</code></td>
639 * <td>User's current working directory</td></tr>
640 * </table>
641 * <p>
642 * Multiple paths in a system property value are separated by the path
643 * separator character of the platform.
644 * <p>
645 * Note that even if the security manager does not permit the
646 * <code>getProperties</code> operation, it may choose to permit the
647 * {@link #getProperty(String)} operation.
648 *
649 * @implNote In addition to the standard system properties, the system
650 * properties may include the following keys:
651 * <table summary="Shows property keys and associated values">
652 * <tr><th>Key</th>
653 * <th>Description of Associated Value</th></tr>
654 * <tr><td>{@code jdk.module.path}</td>
655 * <td>The application module path</td></tr>
656 * <tr><td>{@code jdk.module.upgrade.path}</td>
657 * <td>The upgrade module path</td></tr>
658 * <tr><td>{@code jdk.module.main}</td>
659 * <td>The module name of the initial/main module</td></tr>
660 * <tr><td>{@code jdk.module.main.class}</td>
661 * <td>The main class name of the initial module</td></tr>
662 * </table>
663 *
664 * @return the system properties
665 * @exception SecurityException if a security manager exists and its
666 * <code>checkPropertiesAccess</code> method doesn't allow access
667 * to the system properties.
668 * @see #setProperties
669 * @see java.lang.SecurityException
670 * @see java.lang.SecurityManager#checkPropertiesAccess()
671 * @see java.util.Properties
672 */
673 public static Properties getProperties() {
674 SecurityManager sm = getSecurityManager();
675 if (sm != null) {
676 sm.checkPropertiesAccess();
677 }
678
679 return props;
680 }
681
682 /**
683 * Returns the system-dependent line separator string. It always
684 * returns the same value - the initial value of the {@linkplain
685 * #getProperty(String) system property} {@code line.separator}.
686 *
687 * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
688 * Windows systems it returns {@code "\r\n"}.
689 *
690 * @return the system-dependent line separator string
691 * @since 1.7
692 */
693 public static String lineSeparator() {
694 return lineSeparator;
695 }
696
697 private static String lineSeparator;
698
699 /**
700 * Sets the system properties to the <code>Properties</code>
701 * argument.
702 * <p>
703 * First, if there is a security manager, its
704 * <code>checkPropertiesAccess</code> method is called with no
705 * arguments. This may result in a security exception.
706 * <p>
707 * The argument becomes the current set of system properties for use
708 * by the {@link #getProperty(String)} method. If the argument is
709 * <code>null</code>, then the current set of system properties is
710 * forgotten.
711 *
712 * @param props the new system properties.
713 * @exception SecurityException if a security manager exists and its
714 * <code>checkPropertiesAccess</code> method doesn't allow access
715 * to the system properties.
716 * @see #getProperties
717 * @see java.util.Properties
718 * @see java.lang.SecurityException
719 * @see java.lang.SecurityManager#checkPropertiesAccess()
720 */
721 public static void setProperties(Properties props) {
722 SecurityManager sm = getSecurityManager();
723 if (sm != null) {
724 sm.checkPropertiesAccess();
725 }
726 if (props == null) {
727 props = new Properties();
728 initProperties(props);
729 }
730 System.props = props;
731 }
732
733 /**
734 * Gets the system property indicated by the specified key.
735 * <p>
736 * First, if there is a security manager, its
737 * <code>checkPropertyAccess</code> method is called with the key as
738 * its argument. This may result in a SecurityException.
739 * <p>
740 * If there is no current set of system properties, a set of system
741 * properties is first created and initialized in the same manner as
742 * for the <code>getProperties</code> method.
743 *
744 * @param key the name of the system property.
745 * @return the string value of the system property,
746 * or <code>null</code> if there is no property with that key.
747 *
748 * @exception SecurityException if a security manager exists and its
749 * <code>checkPropertyAccess</code> method doesn't allow
750 * access to the specified system property.
751 * @exception NullPointerException if <code>key</code> is
752 * <code>null</code>.
753 * @exception IllegalArgumentException if <code>key</code> is empty.
754 * @see #setProperty
755 * @see java.lang.SecurityException
756 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
757 * @see java.lang.System#getProperties()
758 */
759 public static String getProperty(String key) {
760 checkKey(key);
761 SecurityManager sm = getSecurityManager();
762 if (sm != null) {
763 sm.checkPropertyAccess(key);
764 }
765
766 return props.getProperty(key);
767 }
768
769 /**
770 * Gets the system property indicated by the specified key.
771 * <p>
772 * First, if there is a security manager, its
773 * <code>checkPropertyAccess</code> method is called with the
774 * <code>key</code> as its argument.
775 * <p>
776 * If there is no current set of system properties, a set of system
777 * properties is first created and initialized in the same manner as
778 * for the <code>getProperties</code> method.
779 *
780 * @param key the name of the system property.
781 * @param def a default value.
782 * @return the string value of the system property,
783 * or the default value if there is no property with that key.
784 *
785 * @exception SecurityException if a security manager exists and its
786 * <code>checkPropertyAccess</code> method doesn't allow
787 * access to the specified system property.
788 * @exception NullPointerException if <code>key</code> is
789 * <code>null</code>.
790 * @exception IllegalArgumentException if <code>key</code> is empty.
791 * @see #setProperty
792 * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
793 * @see java.lang.System#getProperties()
794 */
795 public static String getProperty(String key, String def) {
796 checkKey(key);
797 SecurityManager sm = getSecurityManager();
798 if (sm != null) {
799 sm.checkPropertyAccess(key);
800 }
801
802 return props.getProperty(key, def);
803 }
804
805 /**
806 * Sets the system property indicated by the specified key.
807 * <p>
808 * First, if a security manager exists, its
809 * <code>SecurityManager.checkPermission</code> method
810 * is called with a <code>PropertyPermission(key, "write")</code>
811 * permission. This may result in a SecurityException being thrown.
812 * If no exception is thrown, the specified property is set to the given
813 * value.
814 *
815 * @param key the name of the system property.
816 * @param value the value of the system property.
817 * @return the previous value of the system property,
818 * or <code>null</code> if it did not have one.
819 *
820 * @exception SecurityException if a security manager exists and its
821 * <code>checkPermission</code> method doesn't allow
822 * setting of the specified property.
823 * @exception NullPointerException if <code>key</code> or
824 * <code>value</code> is <code>null</code>.
825 * @exception IllegalArgumentException if <code>key</code> is empty.
826 * @see #getProperty
827 * @see java.lang.System#getProperty(java.lang.String)
828 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
829 * @see java.util.PropertyPermission
830 * @see SecurityManager#checkPermission
831 * @since 1.2
832 */
833 public static String setProperty(String key, String value) {
834 checkKey(key);
835 SecurityManager sm = getSecurityManager();
836 if (sm != null) {
837 sm.checkPermission(new PropertyPermission(key,
838 SecurityConstants.PROPERTY_WRITE_ACTION));
839 }
840
841 return (String) props.setProperty(key, value);
842 }
843
844 /**
845 * Removes the system property indicated by the specified key.
846 * <p>
847 * First, if a security manager exists, its
848 * <code>SecurityManager.checkPermission</code> method
849 * is called with a <code>PropertyPermission(key, "write")</code>
850 * permission. This may result in a SecurityException being thrown.
851 * If no exception is thrown, the specified property is removed.
852 *
853 * @param key the name of the system property to be removed.
854 * @return the previous string value of the system property,
855 * or <code>null</code> if there was no property with that key.
856 *
857 * @exception SecurityException if a security manager exists and its
858 * <code>checkPropertyAccess</code> method doesn't allow
859 * access to the specified system property.
860 * @exception NullPointerException if <code>key</code> is
861 * <code>null</code>.
862 * @exception IllegalArgumentException if <code>key</code> is empty.
863 * @see #getProperty
864 * @see #setProperty
865 * @see java.util.Properties
866 * @see java.lang.SecurityException
867 * @see java.lang.SecurityManager#checkPropertiesAccess()
868 * @since 1.5
869 */
870 public static String clearProperty(String key) {
871 checkKey(key);
872 SecurityManager sm = getSecurityManager();
873 if (sm != null) {
874 sm.checkPermission(new PropertyPermission(key, "write"));
875 }
876
877 return (String) props.remove(key);
878 }
879
880 private static void checkKey(String key) {
881 if (key == null) {
882 throw new NullPointerException("key can't be null");
883 }
884 if (key.equals("")) {
885 throw new IllegalArgumentException("key can't be empty");
886 }
887 }
888
889 /**
890 * Gets the value of the specified environment variable. An
891 * environment variable is a system-dependent external named
892 * value.
893 *
894 * <p>If a security manager exists, its
895 * {@link SecurityManager#checkPermission checkPermission}
896 * method is called with a
897 * <code>{@link RuntimePermission}("getenv."+name)</code>
898 * permission. This may result in a {@link SecurityException}
899 * being thrown. If no exception is thrown the value of the
900 * variable <code>name</code> is returned.
901 *
902 * <p><a id="EnvironmentVSSystemProperties"><i>System
903 * properties</i> and <i>environment variables</i></a> are both
904 * conceptually mappings between names and values. Both
905 * mechanisms can be used to pass user-defined information to a
906 * Java process. Environment variables have a more global effect,
907 * because they are visible to all descendants of the process
908 * which defines them, not just the immediate Java subprocess.
909 * They can have subtly different semantics, such as case
910 * insensitivity, on different operating systems. For these
911 * reasons, environment variables are more likely to have
912 * unintended side effects. It is best to use system properties
913 * where possible. Environment variables should be used when a
914 * global effect is desired, or when an external system interface
915 * requires an environment variable (such as <code>PATH</code>).
916 *
917 * <p>On UNIX systems the alphabetic case of <code>name</code> is
918 * typically significant, while on Microsoft Windows systems it is
919 * typically not. For example, the expression
920 * <code>System.getenv("FOO").equals(System.getenv("foo"))</code>
921 * is likely to be true on Microsoft Windows.
922 *
923 * @param name the name of the environment variable
924 * @return the string value of the variable, or <code>null</code>
925 * if the variable is not defined in the system environment
926 * @throws NullPointerException if <code>name</code> is <code>null</code>
927 * @throws SecurityException
928 * if a security manager exists and its
929 * {@link SecurityManager#checkPermission checkPermission}
930 * method doesn't allow access to the environment variable
931 * <code>name</code>
932 * @see #getenv()
933 * @see ProcessBuilder#environment()
934 */
935 public static String getenv(String name) {
936 SecurityManager sm = getSecurityManager();
937 if (sm != null) {
938 sm.checkPermission(new RuntimePermission("getenv."+name));
939 }
940
941 return ProcessEnvironment.getenv(name);
942 }
943
944
945 /**
946 * Returns an unmodifiable string map view of the current system environment.
947 * The environment is a system-dependent mapping from names to
948 * values which is passed from parent to child processes.
949 *
950 * <p>If the system does not support environment variables, an
951 * empty map is returned.
952 *
953 * <p>The returned map will never contain null keys or values.
954 * Attempting to query the presence of a null key or value will
955 * throw a {@link NullPointerException}. Attempting to query
956 * the presence of a key or value which is not of type
957 * {@link String} will throw a {@link ClassCastException}.
958 *
959 * <p>The returned map and its collection views may not obey the
960 * general contract of the {@link Object#equals} and
961 * {@link Object#hashCode} methods.
962 *
963 * <p>The returned map is typically case-sensitive on all platforms.
964 *
965 * <p>If a security manager exists, its
966 * {@link SecurityManager#checkPermission checkPermission}
967 * method is called with a
968 * <code>{@link RuntimePermission}("getenv.*")</code>
969 * permission. This may result in a {@link SecurityException} being
970 * thrown.
971 *
972 * <p>When passing information to a Java subprocess,
973 * <a href=#EnvironmentVSSystemProperties>system properties</a>
974 * are generally preferred over environment variables.
975 *
976 * @return the environment as a map of variable names to values
977 * @throws SecurityException
978 * if a security manager exists and its
979 * {@link SecurityManager#checkPermission checkPermission}
980 * method doesn't allow access to the process environment
981 * @see #getenv(String)
982 * @see ProcessBuilder#environment()
983 * @since 1.5
984 */
985 public static java.util.Map<String,String> getenv() {
986 SecurityManager sm = getSecurityManager();
987 if (sm != null) {
988 sm.checkPermission(new RuntimePermission("getenv.*"));
989 }
990
991 return ProcessEnvironment.getenv();
992 }
993
994 /**
995 * {@code System.Logger} instances log messages that will be
996 * routed to the underlying logging framework the {@link System.LoggerFinder
997 * LoggerFinder} uses.
998 * <p>
999 * {@code System.Logger} instances are typically obtained from
1000 * the {@link java.lang.System System} class, by calling
1001 * {@link java.lang.System#getLogger(java.lang.String) System.getLogger(loggerName)}
1002 * or {@link java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1003 * System.getLogger(loggerName, bundle)}.
1004 *
1005 * @see java.lang.System#getLogger(java.lang.String)
1006 * @see java.lang.System#getLogger(java.lang.String, java.util.ResourceBundle)
1007 * @see java.lang.System.LoggerFinder
1008 *
1009 * @since 9
1010 *
1011 */
1012 public interface Logger {
1013
1014 /**
1015 * System {@linkplain Logger loggers} levels.
1016 * <p>
1017 * A level has a {@linkplain #getName() name} and {@linkplain
1018 * #getSeverity() severity}.
1019 * Level values are {@link #ALL}, {@link #TRACE}, {@link #DEBUG},
1020 * {@link #INFO}, {@link #WARNING}, {@link #ERROR}, {@link #OFF},
1021 * by order of increasing severity.
1022 * <br>
1023 * {@link #ALL} and {@link #OFF}
1024 * are simple markers with severities mapped respectively to
1025 * {@link java.lang.Integer#MIN_VALUE Integer.MIN_VALUE} and
1026 * {@link java.lang.Integer#MAX_VALUE Integer.MAX_VALUE}.
1027 * <p>
1028 * <b>Severity values and Mapping to {@code java.util.logging.Level}.</b>
1029 * <p>
1030 * {@linkplain System.Logger.Level System logger levels} are mapped to
1031 * {@linkplain java.util.logging.Level java.util.logging levels}
1032 * of corresponding severity.
1033 * <br>The mapping is as follows:
1034 * <br><br>
1035 * <table border="1">
1036 * <caption>System.Logger Severity Level Mapping</caption>
1037 * <tr><td><b>System.Logger Levels</b></td>
1038 * <td>{@link Logger.Level#ALL ALL}</td>
1039 * <td>{@link Logger.Level#TRACE TRACE}</td>
1040 * <td>{@link Logger.Level#DEBUG DEBUG}</td>
1041 * <td>{@link Logger.Level#INFO INFO}</td>
1042 * <td>{@link Logger.Level#WARNING WARNING}</td>
1043 * <td>{@link Logger.Level#ERROR ERROR}</td>
1044 * <td>{@link Logger.Level#OFF OFF}</td>
1045 * </tr>
1046 * <tr><td><b>java.util.logging Levels</b></td>
1047 * <td>{@link java.util.logging.Level#ALL ALL}</td>
1048 * <td>{@link java.util.logging.Level#FINER FINER}</td>
1049 * <td>{@link java.util.logging.Level#FINE FINE}</td>
1050 * <td>{@link java.util.logging.Level#INFO INFO}</td>
1051 * <td>{@link java.util.logging.Level#WARNING WARNING}</td>
1052 * <td>{@link java.util.logging.Level#SEVERE SEVERE}</td>
1053 * <td>{@link java.util.logging.Level#OFF OFF}</td>
1054 * </tr>
1055 * </table>
1056 *
1057 * @since 9
1058 *
1059 * @see java.lang.System.LoggerFinder
1060 * @see java.lang.System.Logger
1061 */
1062 public enum Level {
1063
1064 // for convenience, we're reusing java.util.logging.Level int values
1065 // the mapping logic in sun.util.logging.PlatformLogger depends
1066 // on this.
1067 /**
1068 * A marker to indicate that all levels are enabled.
1069 * This level {@linkplain #getSeverity() severity} is
1070 * {@link Integer#MIN_VALUE}.
1071 */
1072 ALL(Integer.MIN_VALUE), // typically mapped to/from j.u.l.Level.ALL
1073 /**
1074 * {@code TRACE} level: usually used to log diagnostic information.
1075 * This level {@linkplain #getSeverity() severity} is
1076 * {@code 400}.
1077 */
1078 TRACE(400), // typically mapped to/from j.u.l.Level.FINER
1079 /**
1080 * {@code DEBUG} level: usually used to log debug information traces.
1081 * This level {@linkplain #getSeverity() severity} is
1082 * {@code 500}.
1083 */
1084 DEBUG(500), // typically mapped to/from j.u.l.Level.FINEST/FINE/CONFIG
1085 /**
1086 * {@code INFO} level: usually used to log information messages.
1087 * This level {@linkplain #getSeverity() severity} is
1088 * {@code 800}.
1089 */
1090 INFO(800), // typically mapped to/from j.u.l.Level.INFO
1091 /**
1092 * {@code WARNING} level: usually used to log warning messages.
1093 * This level {@linkplain #getSeverity() severity} is
1094 * {@code 900}.
1095 */
1096 WARNING(900), // typically mapped to/from j.u.l.Level.WARNING
1097 /**
1098 * {@code ERROR} level: usually used to log error messages.
1099 * This level {@linkplain #getSeverity() severity} is
1100 * {@code 1000}.
1101 */
1102 ERROR(1000), // typically mapped to/from j.u.l.Level.SEVERE
1103 /**
1104 * A marker to indicate that all levels are disabled.
1105 * This level {@linkplain #getSeverity() severity} is
1106 * {@link Integer#MAX_VALUE}.
1107 */
1108 OFF(Integer.MAX_VALUE); // typically mapped to/from j.u.l.Level.OFF
1109
1110 private final int severity;
1111
1112 private Level(int severity) {
1113 this.severity = severity;
1114 }
1115
1116 /**
1117 * Returns the name of this level.
1118 * @return this level {@linkplain #name()}.
1119 */
1120 public final String getName() {
1121 return name();
1122 }
1123
1124 /**
1125 * Returns the severity of this level.
1126 * A higher severity means a more severe condition.
1127 * @return this level severity.
1128 */
1129 public final int getSeverity() {
1130 return severity;
1131 }
1132 }
1133
1134 /**
1135 * Returns the name of this logger.
1136 *
1137 * @return the logger name.
1138 */
1139 public String getName();
1140
1141 /**
1142 * Checks if a message of the given level would be logged by
1143 * this logger.
1144 *
1145 * @param level the log message level.
1146 * @return {@code true} if the given log message level is currently
1147 * being logged.
1148 *
1149 * @throws NullPointerException if {@code level} is {@code null}.
1150 */
1151 public boolean isLoggable(Level level);
1152
1153 /**
1154 * Logs a message.
1155 *
1156 * @implSpec The default implementation for this method calls
1157 * {@code this.log(level, (ResourceBundle)null, msg, (Object[])null);}
1158 *
1159 * @param level the log message level.
1160 * @param msg the string message (or a key in the message catalog, if
1161 * this logger is a {@link
1162 * LoggerFinder#getLocalizedLogger(java.lang.String,
1163 * java.util.ResourceBundle, java.lang.Module) localized logger});
1164 * can be {@code null}.
1165 *
1166 * @throws NullPointerException if {@code level} is {@code null}.
1167 */
1168 public default void log(Level level, String msg) {
1169 log(level, (ResourceBundle) null, msg, (Object[]) null);
1170 }
1171
1172 /**
1173 * Logs a lazily supplied message.
1174 * <p>
1175 * If the logger is currently enabled for the given log message level
1176 * then a message is logged that is the result produced by the
1177 * given supplier function. Otherwise, the supplier is not operated on.
1178 *
1179 * @implSpec When logging is enabled for the given level, the default
1180 * implementation for this method calls
1181 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), (Object[])null);}
1182 *
1183 * @param level the log message level.
1184 * @param msgSupplier a supplier function that produces a message.
1185 *
1186 * @throws NullPointerException if {@code level} is {@code null},
1187 * or {@code msgSupplier} is {@code null}.
1188 */
1189 public default void log(Level level, Supplier<String> msgSupplier) {
1190 Objects.requireNonNull(msgSupplier);
1191 if (isLoggable(Objects.requireNonNull(level))) {
1192 log(level, (ResourceBundle) null, msgSupplier.get(), (Object[]) null);
1193 }
1194 }
1195
1196 /**
1197 * Logs a message produced from the given object.
1198 * <p>
1199 * If the logger is currently enabled for the given log message level then
1200 * a message is logged that, by default, is the result produced from
1201 * calling toString on the given object.
1202 * Otherwise, the object is not operated on.
1203 *
1204 * @implSpec When logging is enabled for the given level, the default
1205 * implementation for this method calls
1206 * {@code this.log(level, (ResourceBundle)null, obj.toString(), (Object[])null);}
1207 *
1208 * @param level the log message level.
1209 * @param obj the object to log.
1210 *
1211 * @throws NullPointerException if {@code level} is {@code null}, or
1212 * {@code obj} is {@code null}.
1213 */
1214 public default void log(Level level, Object obj) {
1215 Objects.requireNonNull(obj);
1216 if (isLoggable(Objects.requireNonNull(level))) {
1217 this.log(level, (ResourceBundle) null, obj.toString(), (Object[]) null);
1218 }
1219 }
1220
1221 /**
1222 * Logs a message associated with a given throwable.
1223 *
1224 * @implSpec The default implementation for this method calls
1225 * {@code this.log(level, (ResourceBundle)null, msg, thrown);}
1226 *
1227 * @param level the log message level.
1228 * @param msg the string message (or a key in the message catalog, if
1229 * this logger is a {@link
1230 * LoggerFinder#getLocalizedLogger(java.lang.String,
1231 * java.util.ResourceBundle, java.lang.Module) localized logger});
1232 * can be {@code null}.
1233 * @param thrown a {@code Throwable} associated with the log message;
1234 * can be {@code null}.
1235 *
1236 * @throws NullPointerException if {@code level} is {@code null}.
1237 */
1238 public default void log(Level level, String msg, Throwable thrown) {
1239 this.log(level, null, msg, thrown);
1240 }
1241
1242 /**
1243 * Logs a lazily supplied message associated with a given throwable.
1244 * <p>
1245 * If the logger is currently enabled for the given log message level
1246 * then a message is logged that is the result produced by the
1247 * given supplier function. Otherwise, the supplier is not operated on.
1248 *
1249 * @implSpec When logging is enabled for the given level, the default
1250 * implementation for this method calls
1251 * {@code this.log(level, (ResourceBundle)null, msgSupplier.get(), thrown);}
1252 *
1253 * @param level one of the log message level identifiers.
1254 * @param msgSupplier a supplier function that produces a message.
1255 * @param thrown a {@code Throwable} associated with log message;
1256 * can be {@code null}.
1257 *
1258 * @throws NullPointerException if {@code level} is {@code null}, or
1259 * {@code msgSupplier} is {@code null}.
1260 */
1261 public default void log(Level level, Supplier<String> msgSupplier,
1262 Throwable thrown) {
1263 Objects.requireNonNull(msgSupplier);
1264 if (isLoggable(Objects.requireNonNull(level))) {
1265 this.log(level, null, msgSupplier.get(), thrown);
1266 }
1267 }
1268
1269 /**
1270 * Logs a message with an optional list of parameters.
1271 *
1272 * @implSpec The default implementation for this method calls
1273 * {@code this.log(level, (ResourceBundle)null, format, params);}
1274 *
1275 * @param level one of the log message level identifiers.
1276 * @param format the string message format in {@link
1277 * java.text.MessageFormat} format, (or a key in the message
1278 * catalog, if this logger is a {@link
1279 * LoggerFinder#getLocalizedLogger(java.lang.String,
1280 * java.util.ResourceBundle, java.lang.Module) localized logger});
1281 * can be {@code null}.
1282 * @param params an optional list of parameters to the message (may be
1283 * none).
1284 *
1285 * @throws NullPointerException if {@code level} is {@code null}.
1286 */
1287 public default void log(Level level, String format, Object... params) {
1288 this.log(level, null, format, params);
1289 }
1290
1291 /**
1292 * Logs a localized message associated with a given throwable.
1293 * <p>
1294 * If the given resource bundle is non-{@code null}, the {@code msg}
1295 * string is localized using the given resource bundle.
1296 * Otherwise the {@code msg} string is not localized.
1297 *
1298 * @param level the log message level.
1299 * @param bundle a resource bundle to localize {@code msg}; can be
1300 * {@code null}.
1301 * @param msg the string message (or a key in the message catalog,
1302 * if {@code bundle} is not {@code null}); can be {@code null}.
1303 * @param thrown a {@code Throwable} associated with the log message;
1304 * can be {@code null}.
1305 *
1306 * @throws NullPointerException if {@code level} is {@code null}.
1307 */
1308 public void log(Level level, ResourceBundle bundle, String msg,
1309 Throwable thrown);
1310
1311 /**
1312 * Logs a message with resource bundle and an optional list of
1313 * parameters.
1314 * <p>
1315 * If the given resource bundle is non-{@code null}, the {@code format}
1316 * string is localized using the given resource bundle.
1317 * Otherwise the {@code format} string is not localized.
1318 *
1319 * @param level the log message level.
1320 * @param bundle a resource bundle to localize {@code format}; can be
1321 * {@code null}.
1322 * @param format the string message format in {@link
1323 * java.text.MessageFormat} format, (or a key in the message
1324 * catalog if {@code bundle} is not {@code null}); can be {@code null}.
1325 * @param params an optional list of parameters to the message (may be
1326 * none).
1327 *
1328 * @throws NullPointerException if {@code level} is {@code null}.
1329 */
1330 public void log(Level level, ResourceBundle bundle, String format,
1331 Object... params);
1332
1333
1334 }
1335
1336 /**
1337 * The {@code LoggerFinder} service is responsible for creating, managing,
1338 * and configuring loggers to the underlying framework it uses.
1339 * <p>
1340 * A logger finder is a concrete implementation of this class that has a
1341 * zero-argument constructor and implements the abstract methods defined
1342 * by this class.
1343 * The loggers returned from a logger finder are capable of routing log
1344 * messages to the logging backend this provider supports.
1345 * A given invocation of the Java Runtime maintains a single
1346 * system-wide LoggerFinder instance that is loaded as follows:
1347 * <ul>
1348 * <li>First it finds any custom {@code LoggerFinder} provider
1349 * using the {@link java.util.ServiceLoader} facility with the
1350 * {@linkplain ClassLoader#getSystemClassLoader() system class
1351 * loader}.</li>
1352 * <li>If no {@code LoggerFinder} provider is found, the system default
1353 * {@code LoggerFinder} implementation will be used.</li>
1354 * </ul>
1355 * <p>
1356 * An application can replace the logging backend
1357 * <i>even when the java.logging module is present</i>, by simply providing
1358 * and declaring an implementation of the {@link LoggerFinder} service.
1359 * <p>
1360 * <b>Default Implementation</b>
1361 * <p>
1362 * The system default {@code LoggerFinder} implementation uses
1363 * {@code java.util.logging} as the backend framework when the
1364 * {@code java.logging} module is present.
1365 * It returns a {@linkplain System.Logger logger} instance
1366 * that will route log messages to a {@link java.util.logging.Logger
1367 * java.util.logging.Logger}. Otherwise, if {@code java.logging} is not
1368 * present, the default implementation will return a simple logger
1369 * instance that will route log messages of {@code INFO} level and above to
1370 * the console ({@code System.err}).
1371 * <p>
1372 * <b>Logging Configuration</b>
1373 * <p>
1374 * {@linkplain Logger Logger} instances obtained from the
1375 * {@code LoggerFinder} factory methods are not directly configurable by
1376 * the application. Configuration is the responsibility of the underlying
1377 * logging backend, and usually requires using APIs specific to that backend.
1378 * <p>For the default {@code LoggerFinder} implementation
1379 * using {@code java.util.logging} as its backend, refer to
1380 * {@link java.util.logging java.util.logging} for logging configuration.
1381 * For the default {@code LoggerFinder} implementation returning simple loggers
1382 * when the {@code java.logging} module is absent, the configuration
1383 * is implementation dependent.
1384 * <p>
1385 * Usually an application that uses a logging framework will log messages
1386 * through a logger facade defined (or supported) by that framework.
1387 * Applications that wish to use an external framework should log
1388 * through the facade associated with that framework.
1389 * <p>
1390 * A system class that needs to log messages will typically obtain
1391 * a {@link System.Logger} instance to route messages to the logging
1392 * framework selected by the application.
1393 * <p>
1394 * Libraries and classes that only need loggers to produce log messages
1395 * should not attempt to configure loggers by themselves, as that
1396 * would make them dependent from a specific implementation of the
1397 * {@code LoggerFinder} service.
1398 * <p>
1399 * In addition, when a security manager is present, loggers provided to
1400 * system classes should not be directly configurable through the logging
1401 * backend without requiring permissions.
1402 * <br>
1403 * It is the responsibility of the provider of
1404 * the concrete {@code LoggerFinder} implementation to ensure that
1405 * these loggers are not configured by untrusted code without proper
1406 * permission checks, as configuration performed on such loggers usually
1407 * affects all applications in the same Java Runtime.
1408 * <p>
1409 * <b>Message Levels and Mapping to backend levels</b>
1410 * <p>
1411 * A logger finder is responsible for mapping from a {@code
1412 * System.Logger.Level} to a level supported by the logging backend it uses.
1413 * <br>The default LoggerFinder using {@code java.util.logging} as the backend
1414 * maps {@code System.Logger} levels to
1415 * {@linkplain java.util.logging.Level java.util.logging} levels
1416 * of corresponding severity - as described in {@link Logger.Level
1417 * Logger.Level}.
1418 *
1419 * @see java.lang.System
1420 * @see java.lang.System.Logger
1421 *
1422 * @since 9
1423 */
1424 public static abstract class LoggerFinder {
1425 /**
1426 * The {@code RuntimePermission("loggerFinder")} is
1427 * necessary to subclass and instantiate the {@code LoggerFinder} class,
1428 * as well as to obtain loggers from an instance of that class.
1429 */
1430 static final RuntimePermission LOGGERFINDER_PERMISSION =
1431 new RuntimePermission("loggerFinder");
1432
1433 /**
1434 * Creates a new instance of {@code LoggerFinder}.
1435 *
1436 * @implNote It is recommended that a {@code LoggerFinder} service
1437 * implementation does not perform any heavy initialization in its
1438 * constructor, in order to avoid possible risks of deadlock or class
1439 * loading cycles during the instantiation of the service provider.
1440 *
1441 * @throws SecurityException if a security manager is present and its
1442 * {@code checkPermission} method doesn't allow the
1443 * {@code RuntimePermission("loggerFinder")}.
1444 */
1445 protected LoggerFinder() {
1446 this(checkPermission());
1447 }
1448
1449 private LoggerFinder(Void unused) {
1450 // nothing to do.
1451 }
1452
1453 private static Void checkPermission() {
1454 final SecurityManager sm = System.getSecurityManager();
1455 if (sm != null) {
1456 sm.checkPermission(LOGGERFINDER_PERMISSION);
1457 }
1458 return null;
1459 }
1460
1461 /**
1462 * Returns an instance of {@link Logger Logger}
1463 * for the given {@code module}.
1464 *
1465 * @param name the name of the logger.
1466 * @param module the module for which the logger is being requested.
1467 *
1468 * @return a {@link Logger logger} suitable for use within the given
1469 * module.
1470 * @throws NullPointerException if {@code name} is {@code null} or
1471 * {@code module} is {@code null}.
1472 * @throws SecurityException if a security manager is present and its
1473 * {@code checkPermission} method doesn't allow the
1474 * {@code RuntimePermission("loggerFinder")}.
1475 */
1476 public abstract Logger getLogger(String name, Module module);
1477
1478 /**
1479 * Returns a localizable instance of {@link Logger Logger}
1480 * for the given {@code module}.
1481 * The returned logger will use the provided resource bundle for
1482 * message localization.
1483 *
1484 * @implSpec By default, this method calls {@link
1485 * #getLogger(java.lang.String, java.lang.Module)
1486 * this.getLogger(name, module)} to obtain a logger, then wraps that
1487 * logger in a {@link Logger} instance where all methods that do not
1488 * take a {@link ResourceBundle} as parameter are redirected to one
1489 * which does - passing the given {@code bundle} for
1490 * localization. So for instance, a call to {@link
1491 * Logger#log(Level, String) Logger.log(Level.INFO, msg)}
1492 * will end up as a call to {@link
1493 * Logger#log(Level, ResourceBundle, String, Object...)
1494 * Logger.log(Level.INFO, bundle, msg, (Object[])null)} on the wrapped
1495 * logger instance.
1496 * Note however that by default, string messages returned by {@link
1497 * java.util.function.Supplier Supplier<String>} will not be
1498 * localized, as it is assumed that such strings are messages which are
1499 * already constructed, rather than keys in a resource bundle.
1500 * <p>
1501 * An implementation of {@code LoggerFinder} may override this method,
1502 * for example, when the underlying logging backend provides its own
1503 * mechanism for localizing log messages, then such a
1504 * {@code LoggerFinder} would be free to return a logger
1505 * that makes direct use of the mechanism provided by the backend.
1506 *
1507 * @param name the name of the logger.
1508 * @param bundle a resource bundle; can be {@code null}.
1509 * @param module the module for which the logger is being requested.
1510 * @return an instance of {@link Logger Logger} which will use the
1511 * provided resource bundle for message localization.
1512 *
1513 * @throws NullPointerException if {@code name} is {@code null} or
1514 * {@code module} is {@code null}.
1515 * @throws SecurityException if a security manager is present and its
1516 * {@code checkPermission} method doesn't allow the
1517 * {@code RuntimePermission("loggerFinder")}.
1518 */
1519 public Logger getLocalizedLogger(String name, ResourceBundle bundle,
1520 Module module) {
1521 return new LocalizedLoggerWrapper<>(getLogger(name, module), bundle);
1522 }
1523
1524 /**
1525 * Returns the {@code LoggerFinder} instance. There is one
1526 * single system-wide {@code LoggerFinder} instance in
1527 * the Java Runtime. See the class specification of how the
1528 * {@link LoggerFinder LoggerFinder} implementation is located and
1529 * loaded.
1530
1531 * @return the {@link LoggerFinder LoggerFinder} instance.
1532 * @throws SecurityException if a security manager is present and its
1533 * {@code checkPermission} method doesn't allow the
1534 * {@code RuntimePermission("loggerFinder")}.
1535 */
1536 public static LoggerFinder getLoggerFinder() {
1537 final SecurityManager sm = System.getSecurityManager();
1538 if (sm != null) {
1539 sm.checkPermission(LOGGERFINDER_PERMISSION);
1540 }
1541 return accessProvider();
1542 }
1543
1544
1545 private static volatile LoggerFinder service;
1546 static LoggerFinder accessProvider() {
1547 // We do not need to synchronize: LoggerFinderLoader will
1548 // always return the same instance, so if we don't have it,
1549 // just fetch it again.
1550 if (service == null) {
1551 PrivilegedAction<LoggerFinder> pa =
1552 () -> LoggerFinderLoader.getLoggerFinder();
1553 service = AccessController.doPrivileged(pa, null,
1554 LOGGERFINDER_PERMISSION);
1555 }
1556 return service;
1557 }
1558
1559 }
1560
1561
1562 /**
1563 * Returns an instance of {@link Logger Logger} for the caller's
1564 * use.
1565 *
1566 * @implSpec
1567 * Instances returned by this method route messages to loggers
1568 * obtained by calling {@link LoggerFinder#getLogger(java.lang.String,
1569 * java.lang.Module) LoggerFinder.getLogger(name, module)}, where
1570 * {@code module} is the caller's module.
1571 * In cases where {@code System.getLogger} is called from a context where
1572 * there is no caller frame on the stack (e.g when called directly
1573 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1574 * To obtain a logger in such a context, use an auxiliary class that will
1575 * implicitly be identified as the caller, or use the system {@link
1576 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1577 * Note that doing the latter may eagerly initialize the underlying
1578 * logging system.
1579 *
1580 * @apiNote
1581 * This method may defer calling the {@link
1582 * LoggerFinder#getLogger(java.lang.String, java.lang.Module)
1583 * LoggerFinder.getLogger} method to create an actual logger supplied by
1584 * the logging backend, for instance, to allow loggers to be obtained during
1585 * the system initialization time.
1586 *
1587 * @param name the name of the logger.
1588 * @return an instance of {@link Logger} that can be used by the calling
1589 * class.
1590 * @throws NullPointerException if {@code name} is {@code null}.
1591 * @throws IllegalCallerException if there is no Java caller frame on the
1592 * stack.
1593 *
1594 * @since 9
1595 */
1596 @CallerSensitive
1597 public static Logger getLogger(String name) {
1598 Objects.requireNonNull(name);
1599 final Class<?> caller = Reflection.getCallerClass();
1600 if (caller == null) {
1601 throw new IllegalCallerException("no caller frame");
1602 }
1603 return LazyLoggers.getLogger(name, caller.getModule());
1604 }
1605
1606 /**
1607 * Returns a localizable instance of {@link Logger
1608 * Logger} for the caller's use.
1609 * The returned logger will use the provided resource bundle for message
1610 * localization.
1611 *
1612 * @implSpec
1613 * The returned logger will perform message localization as specified
1614 * by {@link LoggerFinder#getLocalizedLogger(java.lang.String,
1615 * java.util.ResourceBundle, java.lang.Module)
1616 * LoggerFinder.getLocalizedLogger(name, bundle, module)}, where
1617 * {@code module} is the caller's module.
1618 * In cases where {@code System.getLogger} is called from a context where
1619 * there is no caller frame on the stack (e.g when called directly
1620 * from a JNI attached thread), {@code IllegalCallerException} is thrown.
1621 * To obtain a logger in such a context, use an auxiliary class that
1622 * will implicitly be identified as the caller, or use the system {@link
1623 * LoggerFinder#getLoggerFinder() LoggerFinder} to obtain a logger instead.
1624 * Note that doing the latter may eagerly initialize the underlying
1625 * logging system.
1626 *
1627 * @apiNote
1628 * This method is intended to be used after the system is fully initialized.
1629 * This method may trigger the immediate loading and initialization
1630 * of the {@link LoggerFinder} service, which may cause issues if the
1631 * Java Runtime is not ready to initialize the concrete service
1632 * implementation yet.
1633 * System classes which may be loaded early in the boot sequence and
1634 * need to log localized messages should create a logger using
1635 * {@link #getLogger(java.lang.String)} and then use the log methods that
1636 * take a resource bundle as parameter.
1637 *
1638 * @param name the name of the logger.
1639 * @param bundle a resource bundle.
1640 * @return an instance of {@link Logger} which will use the provided
1641 * resource bundle for message localization.
1642 * @throws NullPointerException if {@code name} is {@code null} or
1643 * {@code bundle} is {@code null}.
1644 * @throws IllegalCallerException if there is no Java caller frame on the
1645 * stack.
1646 *
1647 * @since 9
1648 */
1649 @CallerSensitive
1650 public static Logger getLogger(String name, ResourceBundle bundle) {
1651 final ResourceBundle rb = Objects.requireNonNull(bundle);
1652 Objects.requireNonNull(name);
1653 final Class<?> caller = Reflection.getCallerClass();
1654 if (caller == null) {
1655 throw new IllegalCallerException("no caller frame");
1656 }
1657 final SecurityManager sm = System.getSecurityManager();
1658 // We don't use LazyLoggers if a resource bundle is specified.
1659 // Bootstrap sensitive classes in the JDK do not use resource bundles
1660 // when logging. This could be revisited later, if it needs to.
1661 if (sm != null) {
1662 final PrivilegedAction<Logger> pa =
1663 () -> LoggerFinder.accessProvider()
1664 .getLocalizedLogger(name, rb, caller.getModule());
1665 return AccessController.doPrivileged(pa, null,
1666 LoggerFinder.LOGGERFINDER_PERMISSION);
1667 }
1668 return LoggerFinder.accessProvider()
1669 .getLocalizedLogger(name, rb, caller.getModule());
1670 }
1671
1672 /**
1673 * Terminates the currently running Java Virtual Machine. The
1674 * argument serves as a status code; by convention, a nonzero status
1675 * code indicates abnormal termination.
1676 * <p>
1677 * This method calls the <code>exit</code> method in class
1678 * <code>Runtime</code>. This method never returns normally.
1679 * <p>
1680 * The call <code>System.exit(n)</code> is effectively equivalent to
1681 * the call:
1682 * <blockquote><pre>
1683 * Runtime.getRuntime().exit(n)
1684 * </pre></blockquote>
1685 *
1686 * @param status exit status.
1687 * @throws SecurityException
1688 * if a security manager exists and its <code>checkExit</code>
1689 * method doesn't allow exit with the specified status.
1690 * @see java.lang.Runtime#exit(int)
1691 */
1692 public static void exit(int status) {
1693 Runtime.getRuntime().exit(status);
1694 }
1695
1696 /**
1697 * Runs the garbage collector.
1698 * <p>
1699 * Calling the <code>gc</code> method suggests that the Java Virtual
1700 * Machine expend effort toward recycling unused objects in order to
1701 * make the memory they currently occupy available for quick reuse.
1702 * When control returns from the method call, the Java Virtual
1703 * Machine has made a best effort to reclaim space from all discarded
1704 * objects.
1705 * <p>
1706 * The call <code>System.gc()</code> is effectively equivalent to the
1707 * call:
1708 * <blockquote><pre>
1709 * Runtime.getRuntime().gc()
1710 * </pre></blockquote>
1711 *
1712 * @see java.lang.Runtime#gc()
1713 */
1714 public static void gc() {
1715 Runtime.getRuntime().gc();
1716 }
1717
1718 /**
1719 * Runs the finalization methods of any objects pending finalization.
1720 * <p>
1721 * Calling this method suggests that the Java Virtual Machine expend
1722 * effort toward running the <code>finalize</code> methods of objects
1723 * that have been found to be discarded but whose <code>finalize</code>
1724 * methods have not yet been run. When control returns from the
1725 * method call, the Java Virtual Machine has made a best effort to
1726 * complete all outstanding finalizations.
1727 * <p>
1728 * The call <code>System.runFinalization()</code> is effectively
1729 * equivalent to the call:
1730 * <blockquote><pre>
1731 * Runtime.getRuntime().runFinalization()
1732 * </pre></blockquote>
1733 *
1734 * @see java.lang.Runtime#runFinalization()
1735 */
1736 public static void runFinalization() {
1737 Runtime.getRuntime().runFinalization();
1738 }
1739
1740 /**
1741 * Enable or disable finalization on exit; doing so specifies that the
1742 * finalizers of all objects that have finalizers that have not yet been
1743 * automatically invoked are to be run before the Java runtime exits.
1744 * By default, finalization on exit is disabled.
1745 *
1746 * <p>If there is a security manager,
1747 * its <code>checkExit</code> method is first called
1748 * with 0 as its argument to ensure the exit is allowed.
1749 * This could result in a SecurityException.
1750 *
1751 * @deprecated This method is inherently unsafe. It may result in
1752 * finalizers being called on live objects while other threads are
1753 * concurrently manipulating those objects, resulting in erratic
1754 * behavior or deadlock.
1755 * This method is subject to removal in a future version of Java SE.
1756 * @param value indicating enabling or disabling of finalization
1757 * @throws SecurityException
1758 * if a security manager exists and its <code>checkExit</code>
1759 * method doesn't allow the exit.
1760 *
1761 * @see java.lang.Runtime#exit(int)
1762 * @see java.lang.Runtime#gc()
1763 * @see java.lang.SecurityManager#checkExit(int)
1764 * @since 1.1
1765 */
1766 @Deprecated(since="1.2", forRemoval=true)
1767 @SuppressWarnings("removal")
1768 public static void runFinalizersOnExit(boolean value) {
1769 Runtime.runFinalizersOnExit(value);
1770 }
1771
1772 /**
1773 * Loads the native library specified by the filename argument. The filename
1774 * argument must be an absolute path name.
1775 *
1776 * If the filename argument, when stripped of any platform-specific library
1777 * prefix, path, and file extension, indicates a library whose name is,
1778 * for example, L, and a native library called L is statically linked
1779 * with the VM, then the JNI_OnLoad_L function exported by the library
1780 * is invoked rather than attempting to load a dynamic library.
1781 * A filename matching the argument does not have to exist in the
1782 * file system.
1783 * See the JNI Specification for more details.
1784 *
1785 * Otherwise, the filename argument is mapped to a native library image in
1786 * an implementation-dependent manner.
1787 *
1788 * <p>
1789 * The call <code>System.load(name)</code> is effectively equivalent
1790 * to the call:
1791 * <blockquote><pre>
1792 * Runtime.getRuntime().load(name)
1793 * </pre></blockquote>
1794 *
1795 * @param filename the file to load.
1796 * @exception SecurityException if a security manager exists and its
1797 * <code>checkLink</code> method doesn't allow
1798 * loading of the specified dynamic library
1799 * @exception UnsatisfiedLinkError if either the filename is not an
1800 * absolute path name, the native library is not statically
1801 * linked with the VM, or the library cannot be mapped to
1802 * a native library image by the host system.
1803 * @exception NullPointerException if <code>filename</code> is
1804 * <code>null</code>
1805 * @see java.lang.Runtime#load(java.lang.String)
1806 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1807 */
1808 @CallerSensitive
1809 public static void load(String filename) {
1810 Runtime.getRuntime().load0(Reflection.getCallerClass(), filename);
1811 }
1812
1813 /**
1814 * Loads the native library specified by the <code>libname</code>
1815 * argument. The <code>libname</code> argument must not contain any platform
1816 * specific prefix, file extension or path. If a native library
1817 * called <code>libname</code> is statically linked with the VM, then the
1818 * JNI_OnLoad_<code>libname</code> function exported by the library is invoked.
1819 * See the JNI Specification for more details.
1820 *
1821 * Otherwise, the libname argument is loaded from a system library
1822 * location and mapped to a native library image in an implementation-
1823 * dependent manner.
1824 * <p>
1825 * The call <code>System.loadLibrary(name)</code> is effectively
1826 * equivalent to the call
1827 * <blockquote><pre>
1828 * Runtime.getRuntime().loadLibrary(name)
1829 * </pre></blockquote>
1830 *
1831 * @param libname the name of the library.
1832 * @exception SecurityException if a security manager exists and its
1833 * <code>checkLink</code> method doesn't allow
1834 * loading of the specified dynamic library
1835 * @exception UnsatisfiedLinkError if either the libname argument
1836 * contains a file path, the native library is not statically
1837 * linked with the VM, or the library cannot be mapped to a
1838 * native library image by the host system.
1839 * @exception NullPointerException if <code>libname</code> is
1840 * <code>null</code>
1841 * @see java.lang.Runtime#loadLibrary(java.lang.String)
1842 * @see java.lang.SecurityManager#checkLink(java.lang.String)
1843 */
1844 @CallerSensitive
1845 public static void loadLibrary(String libname) {
1846 Runtime.getRuntime().loadLibrary0(Reflection.getCallerClass(), libname);
1847 }
1848
1849 /**
1850 * Maps a library name into a platform-specific string representing
1851 * a native library.
1852 *
1853 * @param libname the name of the library.
1854 * @return a platform-dependent native library name.
1855 * @exception NullPointerException if <code>libname</code> is
1856 * <code>null</code>
1857 * @see java.lang.System#loadLibrary(java.lang.String)
1858 * @see java.lang.ClassLoader#findLibrary(java.lang.String)
1859 * @since 1.2
1860 */
1861 public static native String mapLibraryName(String libname);
1862
1863 /**
1864 * Create PrintStream for stdout/err based on encoding.
1865 */
1866 private static PrintStream newPrintStream(FileOutputStream fos, String enc) {
1867 if (enc != null) {
1868 try {
1869 return new PrintStream(new BufferedOutputStream(fos, 128), true, enc);
1870 } catch (UnsupportedEncodingException uee) {}
1871 }
1872 return new PrintStream(new BufferedOutputStream(fos, 128), true);
1873 }
1874
1875 /**
1876 * Logs an exception/error at initialization time to stdout or stderr.
1877 *
1878 * @param printToStderr to print to stderr rather than stdout
1879 * @param printStackTrace to print the stack trace
1880 * @param msg the message to print before the exception, can be {@code null}
1881 * @param e the exception or error
1882 */
1883 private static void logInitException(boolean printToStderr,
1884 boolean printStackTrace,
1885 String msg,
1886 Throwable e) {
1887 if (VM.initLevel() < 1) {
1888 throw new InternalError("system classes not initialized");
1889 }
1890 PrintStream log = (printToStderr) ? err : out;
1891 if (msg != null) {
1892 log.println(msg);
1893 }
1894 if (printStackTrace) {
1895 e.printStackTrace(log);
1896 } else {
1897 log.println(e);
1898 for (Throwable suppressed : e.getSuppressed()) {
1899 log.println("Suppressed: " + suppressed);
1900 }
1901 Throwable cause = e.getCause();
1902 if (cause != null) {
1903 log.println("Caused by: " + cause);
1904 }
1905 }
1906 }
1907
1908 /**
1909 * Initialize the system class. Called after thread initialization.
1910 */
1911 private static void initPhase1() {
1912
1913 // VM might invoke JNU_NewStringPlatform() to set those encoding
1914 // sensitive properties (user.home, user.name, boot.class.path, etc.)
1915 // during "props" initialization, in which it may need access, via
1916 // System.getProperty(), to the related system encoding property that
1917 // have been initialized (put into "props") at early stage of the
1918 // initialization. So make sure the "props" is available at the
1919 // very beginning of the initialization and all system properties to
1920 // be put into it directly.
1921 props = new Properties();
1922 initProperties(props); // initialized by the VM
1923
1924 // There are certain system configurations that may be controlled by
1925 // VM options such as the maximum amount of direct memory and
1926 // Integer cache size used to support the object identity semantics
1927 // of autoboxing. Typically, the library will obtain these values
1928 // from the properties set by the VM. If the properties are for
1929 // internal implementation use only, these properties should be
1930 // removed from the system properties.
1931 //
1932 // See java.lang.Integer.IntegerCache and the
1933 // VM.saveAndRemoveProperties method for example.
1934 //
1935 // Save a private copy of the system properties object that
1936 // can only be accessed by the internal implementation. Remove
1937 // certain system properties that are not intended for public access.
1938 VM.saveAndRemoveProperties(props);
1939
1940 lineSeparator = props.getProperty("line.separator");
1941 VersionProps.init();
1942
1943 FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
1944 FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
1945 FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
1946 setIn0(new BufferedInputStream(fdIn));
1947 setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
1948 setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
1949
1950 // Load the zip library now in order to keep java.util.zip.ZipFile
1951 // from trying to use itself to load this library later.
1952 loadLibrary("zip");
1953
1954 // Setup Java signal handlers for HUP, TERM, and INT (where available).
1955 Terminator.setup();
1956
1957 // Initialize any miscellaneous operating system settings that need to be
1958 // set for the class libraries. Currently this is no-op everywhere except
1959 // for Windows where the process-wide error mode is set before the java.io
1960 // classes are used.
1961 VM.initializeOSEnvironment();
1962
1963 // The main thread is not added to its thread group in the same
1964 // way as other threads; we must do it ourselves here.
1965 Thread current = Thread.currentThread();
1966 current.getThreadGroup().add(current);
1967
1968 // register shared secrets
1969 setJavaLangAccess();
1970
1971 // Subsystems that are invoked during initialization can invoke
1972 // VM.isBooted() in order to avoid doing things that should
1973 // wait until the VM is fully initialized. The initialization level
1974 // is incremented from 0 to 1 here to indicate the first phase of
1975 // initialization has completed.
1976 // IMPORTANT: Ensure that this remains the last initialization action!
1977 VM.initLevel(1);
1978 }
1979
1980 // @see #initPhase2()
1981 static ModuleLayer bootLayer;
1982
1983 /*
1984 * Invoked by VM. Phase 2 module system initialization.
1985 * Only classes in java.base can be loaded in this phase.
1986 *
1987 * @param printToStderr print exceptions to stderr rather than stdout
1988 * @param printStackTrace print stack trace when exception occurs
1989 *
1990 * @return JNI_OK for success, JNI_ERR for failure
1991 */
1992 private static int initPhase2(boolean printToStderr, boolean printStackTrace) {
1993 try {
1994 bootLayer = ModuleBootstrap.boot();
1995 } catch (Exception | Error e) {
1996 logInitException(printToStderr, printStackTrace,
1997 "Error occurred during initialization of boot layer", e);
1998 return -1; // JNI_ERR
1999 }
2000
2001 // module system initialized
2002 VM.initLevel(2);
2003
2004 return 0; // JNI_OK
2005 }
2006
2007 /*
2008 * Invoked by VM. Phase 3 is the final system initialization:
2009 * 1. set security manager
2010 * 2. set system class loader
2011 * 3. set TCCL
2012 *
2013 * This method must be called after the module system initialization.
2014 * The security manager and system class loader may be custom class from
2015 * the application classpath or modulepath.
2016 */
2017 private static void initPhase3() {
2018 // set security manager
2019 String cn = System.getProperty("java.security.manager");
2020 if (cn != null) {
2021 if (cn.isEmpty() || "default".equals(cn)) {
2022 System.setSecurityManager(new SecurityManager());
2023 } else {
2024 try {
2025 Class<?> c = Class.forName(cn, false, ClassLoader.getBuiltinAppClassLoader());
2026 Constructor<?> ctor = c.getConstructor();
2027 // Must be a public subclass of SecurityManager with
2028 // a public no-arg constructor
2029 if (!SecurityManager.class.isAssignableFrom(c) ||
2030 !Modifier.isPublic(c.getModifiers()) ||
2031 !Modifier.isPublic(ctor.getModifiers())) {
2032 throw new Error("Could not create SecurityManager: " + ctor.toString());
2033 }
2034 // custom security manager implementation may be in unnamed module
2035 // or a named module but non-exported package
2036 ctor.setAccessible(true);
2037 SecurityManager sm = (SecurityManager) ctor.newInstance();
2038 System.setSecurityManager(sm);
2039 } catch (Exception e) {
2040 throw new Error("Could not create SecurityManager", e);
2041 }
2042 }
2043 }
2044
2045 // initializing the system class loader
2046 VM.initLevel(3);
2047
2048 // system class loader initialized
2049 ClassLoader scl = ClassLoader.initSystemClassLoader();
2050
2051 // set TCCL
2052 Thread.currentThread().setContextClassLoader(scl);
2053
2054 // system is fully initialized
2055 VM.initLevel(4);
2056 }
2057
2058 private static void setJavaLangAccess() {
2059 // Allow privileged classes outside of java.lang
2060 SharedSecrets.setJavaLangAccess(new JavaLangAccess() {
2061 public Method getMethodOrNull(Class<?> klass, String name, Class<?>... parameterTypes) {
2062 return klass.getMethodOrNull(name, parameterTypes);
2063 }
2064 public jdk.internal.reflect.ConstantPool getConstantPool(Class<?> klass) {
2065 return klass.getConstantPool();
2066 }
2067 public boolean casAnnotationType(Class<?> klass, AnnotationType oldType, AnnotationType newType) {
2068 return klass.casAnnotationType(oldType, newType);
2069 }
2070 public AnnotationType getAnnotationType(Class<?> klass) {
2071 return klass.getAnnotationType();
2072 }
2073 public Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap(Class<?> klass) {
2074 return klass.getDeclaredAnnotationMap();
2075 }
2076 public byte[] getRawClassAnnotations(Class<?> klass) {
2077 return klass.getRawAnnotations();
2078 }
2079 public byte[] getRawClassTypeAnnotations(Class<?> klass) {
2080 return klass.getRawTypeAnnotations();
2081 }
2082 public byte[] getRawExecutableTypeAnnotations(Executable executable) {
2083 return Class.getExecutableTypeAnnotationBytes(executable);
2084 }
2085 public <E extends Enum<E>>
2086 E[] getEnumConstantsShared(Class<E> klass) {
2087 return klass.getEnumConstantsShared();
2088 }
2089 public void blockedOn(Thread t, Interruptible b) {
2090 t.blockedOn(b);
2091 }
2092 public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
2093 Shutdown.add(slot, registerShutdownInProgress, hook);
2094 }
2095 public String newStringUnsafe(char[] chars) {
2096 return new String(chars, true);
2097 }
2098 public Thread newThreadWithAcc(Runnable target, AccessControlContext acc) {
2099 return new Thread(target, acc);
2100 }
2101 @SuppressWarnings("deprecation")
2102 public void invokeFinalize(Object o) throws Throwable {
2103 o.finalize();
2104 }
2105 public ConcurrentHashMap<?, ?> createOrGetClassLoaderValueMap(ClassLoader cl) {
2106 return cl.createOrGetClassLoaderValueMap();
2107 }
2108 public Class<?> defineClass(ClassLoader loader, String name, byte[] b, ProtectionDomain pd, String source) {
2109 return ClassLoader.defineClass1(loader, name, b, 0, b.length, pd, source);
2110 }
2111 public Class<?> findBootstrapClassOrNull(ClassLoader cl, String name) {
2112 return cl.findBootstrapClassOrNull(name);
2113 }
2114 public URL findResource(ClassLoader cl, String mn, String name) throws IOException {
2115 return cl.findResource(mn, name);
2116 }
2117 public Stream<Package> packages(ClassLoader cl) {
2118 return cl.packages();
2119 }
2120 public Package definePackage(ClassLoader cl, String name, Module module) {
2121 return cl.definePackage(name, module);
2122 }
2123 public String fastUUID(long lsb, long msb) {
2124 return Long.fastUUID(lsb, msb);
2125 }
2126 public void invalidatePackageAccessCache() {
2127 SecurityManager.invalidatePackageAccessCache();
2128 }
2129 public Module defineModule(ClassLoader loader,
2130 ModuleDescriptor descriptor,
2131 URI uri) {
2132 return new Module(null, loader, descriptor, uri);
2133 }
2134 public Module defineUnnamedModule(ClassLoader loader) {
2135 return new Module(loader);
2136 }
2137 public void addReads(Module m1, Module m2) {
2138 m1.implAddReads(m2);
2139 }
2140 public void addReadsAllUnnamed(Module m) {
2141 m.implAddReadsAllUnnamed();
2142 }
2143 public void addExports(Module m, String pn, Module other) {
2144 m.implAddExports(pn, other);
2145 }
2146 public void addExportsToAllUnnamed(Module m, String pn) {
2147 m.implAddExportsToAllUnnamed(pn);
2148 }
2149 public void addOpens(Module m, String pn, Module other) {
2150 m.implAddOpens(pn, other);
2151 }
2152 public void addOpensToAllUnnamed(Module m, String pn) {
2153 m.implAddOpensToAllUnnamed(pn);
2154 }
2155 public void addUses(Module m, Class<?> service) {
2156 m.implAddUses(service);
2157 }
2158 public ServicesCatalog getServicesCatalog(ModuleLayer layer) {
2159 return layer.getServicesCatalog();
2160 }
2161 public Stream<ModuleLayer> layers(ModuleLayer layer) {
2162 return layer.layers();
2163 }
2164 public Stream<ModuleLayer> layers(ClassLoader loader) {
2165 return ModuleLayer.layers(loader);
2166 }
2167 });
2168 }
2169 }