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