1 /*
   2  * Copyright (c) 1994, 2013, 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.*;
  28 import java.lang.reflect.Executable;
  29 import java.util.Properties;
  30 import java.util.PropertyPermission;
  31 import java.util.StringTokenizer;
  32 import java.security.AccessController;
  33 import java.security.PrivilegedAction;
  34 import java.security.AllPermission;
  35 import java.nio.channels.Channel;
  36 import java.nio.channels.spi.SelectorProvider;
  37 import sun.nio.ch.Interruptible;
  38 import sun.reflect.Reflection;
  39 import sun.security.util.SecurityConstants;
  40 import sun.reflect.annotation.AnnotationType;
  41 
  42 /**
  43  * The <code>System</code> class contains several useful class fields
  44  * and methods. It cannot be instantiated.
  45  *
  46  * <p>Among the facilities provided by the <code>System</code> class
  47  * are standard input, standard output, and error output streams;
  48  * access to externally defined properties and environment
  49  * variables; a means of loading files and libraries; and a utility
  50  * method for quickly copying a portion of an array.
  51  *
  52  * @author  unascribed
  53  * @since   JDK1.0
  54  */
  55 public final class System {
  56 
  57     /* register the natives via the static initializer.
  58      *
  59      * VM will invoke the initializeSystemClass method to complete
  60      * the initialization for this class separated from clinit.
  61      * Note that to use properties set by the VM, see the constraints
  62      * described in the initializeSystemClass method.
  63      */
  64     private static native void registerNatives();
  65     static {
  66         registerNatives();
  67     }
  68 
  69     /** Don't let anyone instantiate this class */
  70     private System() {
  71     }
  72 
  73     /**
  74      * The "standard" input stream. This stream is already
  75      * open and ready to supply input data. Typically this stream
  76      * corresponds to keyboard input or another input source specified by
  77      * the host environment or user.
  78      */
  79     public final static InputStream in = null;
  80 
  81     /**
  82      * The "standard" output stream. This stream is already
  83      * open and ready to accept output data. Typically this stream
  84      * corresponds to display output or another output destination
  85      * specified by the host environment or user.
  86      * <p>
  87      * For simple stand-alone Java applications, a typical way to write
  88      * a line of output data is:
  89      * <blockquote><pre>
  90      *     System.out.println(data)
  91      * </pre></blockquote>
  92      * <p>
  93      * See the <code>println</code> methods in class <code>PrintStream</code>.
  94      *
  95      * @see     java.io.PrintStream#println()
  96      * @see     java.io.PrintStream#println(boolean)
  97      * @see     java.io.PrintStream#println(char)
  98      * @see     java.io.PrintStream#println(char[])
  99      * @see     java.io.PrintStream#println(double)
 100      * @see     java.io.PrintStream#println(float)
 101      * @see     java.io.PrintStream#println(int)
 102      * @see     java.io.PrintStream#println(long)
 103      * @see     java.io.PrintStream#println(java.lang.Object)
 104      * @see     java.io.PrintStream#println(java.lang.String)
 105      */
 106     public final static PrintStream out = null;
 107 
 108     /**
 109      * The "standard" error output stream. This stream is already
 110      * open and ready to accept output data.
 111      * <p>
 112      * Typically this stream corresponds to display output or another
 113      * output destination specified by the host environment or user. By
 114      * convention, this output stream is used to display error messages
 115      * or other information that should come to the immediate attention
 116      * of a user even if the principal output stream, the value of the
 117      * variable <code>out</code>, has been redirected to a file or other
 118      * destination that is typically not continuously monitored.
 119      */
 120     public final static PrintStream err = null;
 121 
 122     /* The security manager for the system.
 123      */
 124     private static volatile SecurityManager security = null;
 125 
 126     /**
 127      * Reassigns the "standard" input stream.
 128      *
 129      * <p>First, if there is a security manager, its <code>checkPermission</code>
 130      * method is called with a <code>RuntimePermission("setIO")</code> permission
 131      *  to see if it's ok to reassign the "standard" input stream.
 132      * <p>
 133      *
 134      * @param in the new standard input stream.
 135      *
 136      * @throws SecurityException
 137      *        if a security manager exists and its
 138      *        <code>checkPermission</code> method doesn't allow
 139      *        reassigning of the standard input stream.
 140      *
 141      * @see SecurityManager#checkPermission
 142      * @see java.lang.RuntimePermission
 143      *
 144      * @since   JDK1.1
 145      */
 146     public static void setIn(InputStream in) {
 147         checkIO();
 148         setIn0(in);
 149     }
 150 
 151     /**
 152      * Reassigns the "standard" output stream.
 153      *
 154      * <p>First, if there is a security manager, its <code>checkPermission</code>
 155      * method is called with a <code>RuntimePermission("setIO")</code> permission
 156      *  to see if it's ok to reassign the "standard" output stream.
 157      *
 158      * @param out the new standard output stream
 159      *
 160      * @throws SecurityException
 161      *        if a security manager exists and its
 162      *        <code>checkPermission</code> method doesn't allow
 163      *        reassigning of the standard output stream.
 164      *
 165      * @see SecurityManager#checkPermission
 166      * @see java.lang.RuntimePermission
 167      *
 168      * @since   JDK1.1
 169      */
 170     public static void setOut(PrintStream out) {
 171         checkIO();
 172         setOut0(out);
 173     }
 174 
 175     /**
 176      * Reassigns the "standard" error output stream.
 177      *
 178      * <p>First, if there is a security manager, its <code>checkPermission</code>
 179      * method is called with a <code>RuntimePermission("setIO")</code> permission
 180      *  to see if it's ok to reassign the "standard" error output stream.
 181      *
 182      * @param err the new standard error output stream.
 183      *
 184      * @throws SecurityException
 185      *        if a security manager exists and its
 186      *        <code>checkPermission</code> method doesn't allow
 187      *        reassigning of the standard error output stream.
 188      *
 189      * @see SecurityManager#checkPermission
 190      * @see java.lang.RuntimePermission
 191      *
 192      * @since   JDK1.1
 193      */
 194     public static void setErr(PrintStream err) {
 195         checkIO();
 196         setErr0(err);
 197     }
 198 
 199     private static volatile Console cons = null;
 200     /**
 201      * Returns the unique {@link java.io.Console Console} object associated
 202      * with the current Java virtual machine, if any.
 203      *
 204      * @return  The system console, if any, otherwise <tt>null</tt>.
 205      *
 206      * @since   1.6
 207      */
 208      public static Console console() {
 209          if (cons == null) {
 210              synchronized (System.class) {
 211                  cons = sun.misc.SharedSecrets.getJavaIOAccess().console();
 212              }
 213          }
 214          return cons;
 215      }
 216 
 217     /**
 218      * Returns the channel inherited from the entity that created this
 219      * Java virtual machine.
 220      *
 221      * <p> This method returns the channel obtained by invoking the
 222      * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
 223      * inheritedChannel} method of the system-wide default
 224      * {@link java.nio.channels.spi.SelectorProvider} object. </p>
 225      *
 226      * <p> In addition to the network-oriented channels described in
 227      * {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
 228      * inheritedChannel}, this method may return other kinds of
 229      * channels in the future.
 230      *
 231      * @return  The inherited channel, if any, otherwise <tt>null</tt>.
 232      *
 233      * @throws  IOException
 234      *          If an I/O error occurs
 235      *
 236      * @throws  SecurityException
 237      *          If a security manager is present and it does not
 238      *          permit access to the channel.
 239      *
 240      * @since 1.5
 241      */
 242     public static Channel inheritedChannel() throws IOException {
 243         return SelectorProvider.provider().inheritedChannel();
 244     }
 245 
 246     private static void checkIO() {
 247         SecurityManager sm = getSecurityManager();
 248         if (sm != null) {
 249             sm.checkPermission(new RuntimePermission("setIO"));
 250         }
 251     }
 252 
 253     private static native void setIn0(InputStream in);
 254     private static native void setOut0(PrintStream out);
 255     private static native void setErr0(PrintStream err);
 256 
 257     /**
 258      * Sets the System security.
 259      *
 260      * <p> If there is a security manager already installed, this method first
 261      * calls the security manager's <code>checkPermission</code> method
 262      * with a <code>RuntimePermission("setSecurityManager")</code>
 263      * permission to ensure it's ok to replace the existing
 264      * security manager.
 265      * This may result in throwing a <code>SecurityException</code>.
 266      *
 267      * <p> Otherwise, the argument is established as the current
 268      * security manager. If the argument is <code>null</code> and no
 269      * security manager has been established, then no action is taken and
 270      * the method simply returns.
 271      *
 272      * @param      s   the security manager.
 273      * @exception  SecurityException  if the security manager has already
 274      *             been set and its <code>checkPermission</code> method
 275      *             doesn't allow it to be replaced.
 276      * @see #getSecurityManager
 277      * @see SecurityManager#checkPermission
 278      * @see java.lang.RuntimePermission
 279      */
 280     public static
 281     void setSecurityManager(final SecurityManager s) {
 282         try {
 283             s.checkPackageAccess("java.lang");
 284         } catch (Exception e) {
 285             // no-op
 286         }
 287         setSecurityManager0(s);
 288     }
 289 
 290     private static synchronized
 291     void setSecurityManager0(final SecurityManager s) {
 292         SecurityManager sm = getSecurityManager();
 293         if (sm != null) {
 294             // ask the currently installed security manager if we
 295             // can replace it.
 296             sm.checkPermission(new RuntimePermission
 297                                      ("setSecurityManager"));
 298         }
 299 
 300         if ((s != null) && (s.getClass().getClassLoader() != null)) {
 301             // New security manager class is not on bootstrap classpath.
 302             // Cause policy to get initialized before we install the new
 303             // security manager, in order to prevent infinite loops when
 304             // trying to initialize the policy (which usually involves
 305             // accessing some security and/or system properties, which in turn
 306             // calls the installed security manager's checkPermission method
 307             // which will loop infinitely if there is a non-system class
 308             // (in this case: the new security manager class) on the stack).
 309             AccessController.doPrivileged(new PrivilegedAction<Object>() {
 310                 public Object run() {
 311                     s.getClass().getProtectionDomain().implies
 312                         (SecurityConstants.ALL_PERMISSION);
 313                     return null;
 314                 }
 315             });
 316         }
 317 
 318         security = s;
 319     }
 320 
 321     /**
 322      * Gets the system security interface.
 323      *
 324      * @return  if a security manager has already been established for the
 325      *          current application, then that security manager is returned;
 326      *          otherwise, <code>null</code> is returned.
 327      * @see     #setSecurityManager
 328      */
 329     public static SecurityManager getSecurityManager() {
 330         return security;
 331     }
 332 
 333     /**
 334      * Returns the current time in milliseconds.  Note that
 335      * while the unit of time of the return value is a millisecond,
 336      * the granularity of the value depends on the underlying
 337      * operating system and may be larger.  For example, many
 338      * operating systems measure time in units of tens of
 339      * milliseconds.
 340      *
 341      * <p> See the description of the class <code>Date</code> for
 342      * a discussion of slight discrepancies that may arise between
 343      * "computer time" and coordinated universal time (UTC).
 344      *
 345      * @return  the difference, measured in milliseconds, between
 346      *          the current time and midnight, January 1, 1970 UTC.
 347      * @see     java.util.Date
 348      */
 349     public static native long currentTimeMillis();
 350 
 351     /**
 352      * Returns the current value of the running Java Virtual Machine's
 353      * high-resolution time source, in nanoseconds.
 354      *
 355      * <p>This method can only be used to measure elapsed time and is
 356      * not related to any other notion of system or wall-clock time.
 357      * The value returned represents nanoseconds since some fixed but
 358      * arbitrary <i>origin</i> time (perhaps in the future, so values
 359      * may be negative).  The same origin is used by all invocations of
 360      * this method in an instance of a Java virtual machine; other
 361      * virtual machine instances are likely to use a different origin.
 362      *
 363      * <p>This method provides nanosecond precision, but not necessarily
 364      * nanosecond resolution (that is, how frequently the value changes)
 365      * - no guarantees are made except that the resolution is at least as
 366      * good as that of {@link #currentTimeMillis()}.
 367      *
 368      * <p>Differences in successive calls that span greater than
 369      * approximately 292 years (2<sup>63</sup> nanoseconds) will not
 370      * correctly compute elapsed time due to numerical overflow.
 371      *
 372      * <p>The values returned by this method become meaningful only when
 373      * the difference between two such values, obtained within the same
 374      * instance of a Java virtual machine, is computed.
 375      *
 376      * <p> For example, to measure how long some code takes to execute:
 377      *  <pre> {@code
 378      * long startTime = System.nanoTime();
 379      * // ... the code being measured ...
 380      * long estimatedTime = System.nanoTime() - startTime;}</pre>
 381      *
 382      * <p>To compare two nanoTime values
 383      *  <pre> {@code
 384      * long t0 = System.nanoTime();
 385      * ...
 386      * long t1 = System.nanoTime();}</pre>
 387      *
 388      * one should use {@code t1 - t0 < 0}, not {@code t1 < t0},
 389      * because of the possibility of numerical overflow.
 390      *
 391      * @return the current value of the running Java Virtual Machine's
 392      *         high-resolution time source, in nanoseconds
 393      * @since 1.5
 394      */
 395     public static native long nanoTime();
 396 
 397     /**
 398      * Copies an array from the specified source array, beginning at the
 399      * specified position, to the specified position of the destination array.
 400      * A subsequence of array components are copied from the source
 401      * array referenced by <code>src</code> to the destination array
 402      * referenced by <code>dest</code>. The number of components copied is
 403      * equal to the <code>length</code> argument. The components at
 404      * positions <code>srcPos</code> through
 405      * <code>srcPos+length-1</code> in the source array are copied into
 406      * positions <code>destPos</code> through
 407      * <code>destPos+length-1</code>, respectively, of the destination
 408      * array.
 409      * <p>
 410      * If the <code>src</code> and <code>dest</code> arguments refer to the
 411      * same array object, then the copying is performed as if the
 412      * components at positions <code>srcPos</code> through
 413      * <code>srcPos+length-1</code> were first copied to a temporary
 414      * array with <code>length</code> components and then the contents of
 415      * the temporary array were copied into positions
 416      * <code>destPos</code> through <code>destPos+length-1</code> of the
 417      * destination array.
 418      * <p>
 419      * If <code>dest</code> is <code>null</code>, then a
 420      * <code>NullPointerException</code> is thrown.
 421      * <p>
 422      * If <code>src</code> is <code>null</code>, then a
 423      * <code>NullPointerException</code> is thrown and the destination
 424      * array is not modified.
 425      * <p>
 426      * Otherwise, if any of the following is true, an
 427      * <code>ArrayStoreException</code> is thrown and the destination is
 428      * not modified:
 429      * <ul>
 430      * <li>The <code>src</code> argument refers to an object that is not an
 431      *     array.
 432      * <li>The <code>dest</code> argument refers to an object that is not an
 433      *     array.
 434      * <li>The <code>src</code> argument and <code>dest</code> argument refer
 435      *     to arrays whose component types are different primitive types.
 436      * <li>The <code>src</code> argument refers to an array with a primitive
 437      *    component type and the <code>dest</code> argument refers to an array
 438      *     with a reference component type.
 439      * <li>The <code>src</code> argument refers to an array with a reference
 440      *    component type and the <code>dest</code> argument refers to an array
 441      *     with a primitive component type.
 442      * </ul>
 443      * <p>
 444      * Otherwise, if any of the following is true, an
 445      * <code>IndexOutOfBoundsException</code> is
 446      * thrown and the destination is not modified:
 447      * <ul>
 448      * <li>The <code>srcPos</code> argument is negative.
 449      * <li>The <code>destPos</code> argument is negative.
 450      * <li>The <code>length</code> argument is negative.
 451      * <li><code>srcPos+length</code> is greater than
 452      *     <code>src.length</code>, the length of the source array.
 453      * <li><code>destPos+length</code> is greater than
 454      *     <code>dest.length</code>, the length of the destination array.
 455      * </ul>
 456      * <p>
 457      * Otherwise, if any actual component of the source array from
 458      * position <code>srcPos</code> through
 459      * <code>srcPos+length-1</code> cannot be converted to the component
 460      * type of the destination array by assignment conversion, an
 461      * <code>ArrayStoreException</code> is thrown. In this case, let
 462      * <b><i>k</i></b> be the smallest nonnegative integer less than
 463      * length such that <code>src[srcPos+</code><i>k</i><code>]</code>
 464      * cannot be converted to the component type of the destination
 465      * array; when the exception is thrown, source array components from
 466      * positions <code>srcPos</code> through
 467      * <code>srcPos+</code><i>k</i><code>-1</code>
 468      * will already have been copied to destination array positions
 469      * <code>destPos</code> through
 470      * <code>destPos+</code><i>k</I><code>-1</code> and no other
 471      * positions of the destination array will have been modified.
 472      * (Because of the restrictions already itemized, this
 473      * paragraph effectively applies only to the situation where both
 474      * arrays have component types that are reference types.)
 475      *
 476      * @param      src      the source array.
 477      * @param      srcPos   starting position in the source array.
 478      * @param      dest     the destination array.
 479      * @param      destPos  starting position in the destination data.
 480      * @param      length   the number of array elements to be copied.
 481      * @exception  IndexOutOfBoundsException  if copying would cause
 482      *               access of data outside array bounds.
 483      * @exception  ArrayStoreException  if an element in the <code>src</code>
 484      *               array could not be stored into the <code>dest</code> array
 485      *               because of a type mismatch.
 486      * @exception  NullPointerException if either <code>src</code> or
 487      *               <code>dest</code> is <code>null</code>.
 488      */
 489     public static native void arraycopy(Object src,  int  srcPos,
 490                                         Object dest, int destPos,
 491                                         int length);
 492 
 493     /**
 494      * Returns the same hash code for the given object as
 495      * would be returned by the default method hashCode(),
 496      * whether or not the given object's class overrides
 497      * hashCode().
 498      * The hash code for the null reference is zero.
 499      *
 500      * @param x object for which the hashCode is to be calculated
 501      * @return  the hashCode
 502      * @since   JDK1.1
 503      */
 504     public static native int identityHashCode(Object x);
 505 
 506     /**
 507      * System properties. The following properties are guaranteed to be defined:
 508      * <dl>
 509      * <dt>java.version         <dd>Java version number
 510      * <dt>java.vendor          <dd>Java vendor specific string
 511      * <dt>java.vendor.url      <dd>Java vendor URL
 512      * <dt>java.home            <dd>Java installation directory
 513      * <dt>java.class.version   <dd>Java class version number
 514      * <dt>java.class.path      <dd>Java classpath
 515      * <dt>os.name              <dd>Operating System Name
 516      * <dt>os.arch              <dd>Operating System Architecture
 517      * <dt>os.version           <dd>Operating System Version
 518      * <dt>file.separator       <dd>File separator ("/" on Unix)
 519      * <dt>path.separator       <dd>Path separator (":" on Unix)
 520      * <dt>line.separator       <dd>Line separator ("\n" on Unix)
 521      * <dt>user.name            <dd>User account name
 522      * <dt>user.home            <dd>User home directory
 523      * <dt>user.dir             <dd>User's current working directory
 524      * </dl>
 525      */
 526 
 527     private static Properties props;
 528     private static native Properties initProperties(Properties props);
 529 
 530     /**
 531      * Determines the current system properties.
 532      * <p>
 533      * First, if there is a security manager, its
 534      * <code>checkPropertiesAccess</code> method is called with no
 535      * arguments. This may result in a security exception.
 536      * <p>
 537      * The current set of system properties for use by the
 538      * {@link #getProperty(String)} method is returned as a
 539      * <code>Properties</code> object. If there is no current set of
 540      * system properties, a set of system properties is first created and
 541      * initialized. This set of system properties always includes values
 542      * for the following keys:
 543      * <table summary="Shows property keys and associated values">
 544      * <tr><th>Key</th>
 545      *     <th>Description of Associated Value</th></tr>
 546      * <tr><td><code>java.version</code></td>
 547      *     <td>Java Runtime Environment version</td></tr>
 548      * <tr><td><code>java.vendor</code></td>
 549      *     <td>Java Runtime Environment vendor</td></tr>
 550      * <tr><td><code>java.vendor.url</code></td>
 551      *     <td>Java vendor URL</td></tr>
 552      * <tr><td><code>java.home</code></td>
 553      *     <td>Java installation directory</td></tr>
 554      * <tr><td><code>java.vm.specification.version</code></td>
 555      *     <td>Java Virtual Machine specification version</td></tr>
 556      * <tr><td><code>java.vm.specification.vendor</code></td>
 557      *     <td>Java Virtual Machine specification vendor</td></tr>
 558      * <tr><td><code>java.vm.specification.name</code></td>
 559      *     <td>Java Virtual Machine specification name</td></tr>
 560      * <tr><td><code>java.vm.version</code></td>
 561      *     <td>Java Virtual Machine implementation version</td></tr>
 562      * <tr><td><code>java.vm.vendor</code></td>
 563      *     <td>Java Virtual Machine implementation vendor</td></tr>
 564      * <tr><td><code>java.vm.name</code></td>
 565      *     <td>Java Virtual Machine implementation name</td></tr>
 566      * <tr><td><code>java.specification.version</code></td>
 567      *     <td>Java Runtime Environment specification  version</td></tr>
 568      * <tr><td><code>java.specification.vendor</code></td>
 569      *     <td>Java Runtime Environment specification  vendor</td></tr>
 570      * <tr><td><code>java.specification.name</code></td>
 571      *     <td>Java Runtime Environment specification  name</td></tr>
 572      * <tr><td><code>java.class.version</code></td>
 573      *     <td>Java class format version number</td></tr>
 574      * <tr><td><code>java.class.path</code></td>
 575      *     <td>Java class path</td></tr>
 576      * <tr><td><code>java.library.path</code></td>
 577      *     <td>List of paths to search when loading libraries</td></tr>
 578      * <tr><td><code>java.io.tmpdir</code></td>
 579      *     <td>Default temp file path</td></tr>
 580      * <tr><td><code>java.compiler</code></td>
 581      *     <td>Name of JIT compiler to use</td></tr>
 582      * <tr><td><code>java.ext.dirs</code></td>
 583      *     <td>Path of extension directory or directories</td></tr>
 584      * <tr><td><code>os.name</code></td>
 585      *     <td>Operating system name</td></tr>
 586      * <tr><td><code>os.arch</code></td>
 587      *     <td>Operating system architecture</td></tr>
 588      * <tr><td><code>os.version</code></td>
 589      *     <td>Operating system version</td></tr>
 590      * <tr><td><code>file.separator</code></td>
 591      *     <td>File separator ("/" on UNIX)</td></tr>
 592      * <tr><td><code>path.separator</code></td>
 593      *     <td>Path separator (":" on UNIX)</td></tr>
 594      * <tr><td><code>line.separator</code></td>
 595      *     <td>Line separator ("\n" on UNIX)</td></tr>
 596      * <tr><td><code>user.name</code></td>
 597      *     <td>User's account name</td></tr>
 598      * <tr><td><code>user.home</code></td>
 599      *     <td>User's home directory</td></tr>
 600      * <tr><td><code>user.dir</code></td>
 601      *     <td>User's current working directory</td></tr>
 602      * </table>
 603      * <p>
 604      * Multiple paths in a system property value are separated by the path
 605      * separator character of the platform.
 606      * <p>
 607      * Note that even if the security manager does not permit the
 608      * <code>getProperties</code> operation, it may choose to permit the
 609      * {@link #getProperty(String)} operation.
 610      *
 611      * @return     the system properties
 612      * @exception  SecurityException  if a security manager exists and its
 613      *             <code>checkPropertiesAccess</code> method doesn't allow access
 614      *              to the system properties.
 615      * @see        #setProperties
 616      * @see        java.lang.SecurityException
 617      * @see        java.lang.SecurityManager#checkPropertiesAccess()
 618      * @see        java.util.Properties
 619      */
 620     public static Properties getProperties() {
 621         SecurityManager sm = getSecurityManager();
 622         if (sm != null) {
 623             sm.checkPropertiesAccess();
 624         }
 625 
 626         return props;
 627     }
 628 
 629     /**
 630      * Returns the system-dependent line separator string.  It always
 631      * returns the same value - the initial value of the {@linkplain
 632      * #getProperty(String) system property} {@code line.separator}.
 633      *
 634      * <p>On UNIX systems, it returns {@code "\n"}; on Microsoft
 635      * Windows systems it returns {@code "\r\n"}.
 636      * @since 1.7
 637      */
 638     public static String lineSeparator() {
 639         return lineSeparator;
 640     }
 641 
 642     private static String lineSeparator;
 643 
 644     /**
 645      * Sets the system properties to the <code>Properties</code>
 646      * argument.
 647      * <p>
 648      * First, if there is a security manager, its
 649      * <code>checkPropertiesAccess</code> method is called with no
 650      * arguments. This may result in a security exception.
 651      * <p>
 652      * The argument becomes the current set of system properties for use
 653      * by the {@link #getProperty(String)} method. If the argument is
 654      * <code>null</code>, then the current set of system properties is
 655      * forgotten.
 656      *
 657      * @param      props   the new system properties.
 658      * @exception  SecurityException  if a security manager exists and its
 659      *             <code>checkPropertiesAccess</code> method doesn't allow access
 660      *              to the system properties.
 661      * @see        #getProperties
 662      * @see        java.util.Properties
 663      * @see        java.lang.SecurityException
 664      * @see        java.lang.SecurityManager#checkPropertiesAccess()
 665      */
 666     public static void setProperties(Properties props) {
 667         SecurityManager sm = getSecurityManager();
 668         if (sm != null) {
 669             sm.checkPropertiesAccess();
 670         }
 671         if (props == null) {
 672             props = new Properties();
 673             initProperties(props);
 674         }
 675         System.props = props;
 676     }
 677 
 678     /**
 679      * Gets the system property indicated by the specified key.
 680      * <p>
 681      * First, if there is a security manager, its
 682      * <code>checkPropertyAccess</code> method is called with the key as
 683      * its argument. This may result in a SecurityException.
 684      * <p>
 685      * If there is no current set of system properties, a set of system
 686      * properties is first created and initialized in the same manner as
 687      * for the <code>getProperties</code> method.
 688      *
 689      * @param      key   the name of the system property.
 690      * @return     the string value of the system property,
 691      *             or <code>null</code> if there is no property with that key.
 692      *
 693      * @exception  SecurityException  if a security manager exists and its
 694      *             <code>checkPropertyAccess</code> method doesn't allow
 695      *              access to the specified system property.
 696      * @exception  NullPointerException if <code>key</code> is
 697      *             <code>null</code>.
 698      * @exception  IllegalArgumentException if <code>key</code> is empty.
 699      * @see        #setProperty
 700      * @see        java.lang.SecurityException
 701      * @see        java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
 702      * @see        java.lang.System#getProperties()
 703      */
 704     public static String getProperty(String key) {
 705         checkKey(key);
 706         SecurityManager sm = getSecurityManager();
 707         if (sm != null) {
 708             sm.checkPropertyAccess(key);
 709         }
 710 
 711         return props.getProperty(key);
 712     }
 713 
 714     /**
 715      * Gets the system property indicated by the specified key.
 716      * <p>
 717      * First, if there is a security manager, its
 718      * <code>checkPropertyAccess</code> method is called with the
 719      * <code>key</code> as its argument.
 720      * <p>
 721      * If there is no current set of system properties, a set of system
 722      * properties is first created and initialized in the same manner as
 723      * for the <code>getProperties</code> method.
 724      *
 725      * @param      key   the name of the system property.
 726      * @param      def   a default value.
 727      * @return     the string value of the system property,
 728      *             or the default value if there is no property with that key.
 729      *
 730      * @exception  SecurityException  if a security manager exists and its
 731      *             <code>checkPropertyAccess</code> method doesn't allow
 732      *             access to the specified system property.
 733      * @exception  NullPointerException if <code>key</code> is
 734      *             <code>null</code>.
 735      * @exception  IllegalArgumentException if <code>key</code> is empty.
 736      * @see        #setProperty
 737      * @see        java.lang.SecurityManager#checkPropertyAccess(java.lang.String)
 738      * @see        java.lang.System#getProperties()
 739      */
 740     public static String getProperty(String key, String def) {
 741         checkKey(key);
 742         SecurityManager sm = getSecurityManager();
 743         if (sm != null) {
 744             sm.checkPropertyAccess(key);
 745         }
 746 
 747         return props.getProperty(key, def);
 748     }
 749 
 750     /**
 751      * Sets the system property indicated by the specified key.
 752      * <p>
 753      * First, if a security manager exists, its
 754      * <code>SecurityManager.checkPermission</code> method
 755      * is called with a <code>PropertyPermission(key, "write")</code>
 756      * permission. This may result in a SecurityException being thrown.
 757      * If no exception is thrown, the specified property is set to the given
 758      * value.
 759      * <p>
 760      *
 761      * @param      key   the name of the system property.
 762      * @param      value the value of the system property.
 763      * @return     the previous value of the system property,
 764      *             or <code>null</code> if it did not have one.
 765      *
 766      * @exception  SecurityException  if a security manager exists and its
 767      *             <code>checkPermission</code> method doesn't allow
 768      *             setting of the specified property.
 769      * @exception  NullPointerException if <code>key</code> or
 770      *             <code>value</code> is <code>null</code>.
 771      * @exception  IllegalArgumentException if <code>key</code> is empty.
 772      * @see        #getProperty
 773      * @see        java.lang.System#getProperty(java.lang.String)
 774      * @see        java.lang.System#getProperty(java.lang.String, java.lang.String)
 775      * @see        java.util.PropertyPermission
 776      * @see        SecurityManager#checkPermission
 777      * @since      1.2
 778      */
 779     public static String setProperty(String key, String value) {
 780         checkKey(key);
 781         SecurityManager sm = getSecurityManager();
 782         if (sm != null) {
 783             sm.checkPermission(new PropertyPermission(key,
 784                 SecurityConstants.PROPERTY_WRITE_ACTION));
 785         }
 786 
 787         return (String) props.setProperty(key, value);
 788     }
 789 
 790     /**
 791      * Removes the system property indicated by the specified key.
 792      * <p>
 793      * First, if a security manager exists, its
 794      * <code>SecurityManager.checkPermission</code> method
 795      * is called with a <code>PropertyPermission(key, "write")</code>
 796      * permission. This may result in a SecurityException being thrown.
 797      * If no exception is thrown, the specified property is removed.
 798      * <p>
 799      *
 800      * @param      key   the name of the system property to be removed.
 801      * @return     the previous string value of the system property,
 802      *             or <code>null</code> if there was no property with that key.
 803      *
 804      * @exception  SecurityException  if a security manager exists and its
 805      *             <code>checkPropertyAccess</code> method doesn't allow
 806      *              access to the specified system property.
 807      * @exception  NullPointerException if <code>key</code> is
 808      *             <code>null</code>.
 809      * @exception  IllegalArgumentException if <code>key</code> is empty.
 810      * @see        #getProperty
 811      * @see        #setProperty
 812      * @see        java.util.Properties
 813      * @see        java.lang.SecurityException
 814      * @see        java.lang.SecurityManager#checkPropertiesAccess()
 815      * @since 1.5
 816      */
 817     public static String clearProperty(String key) {
 818         checkKey(key);
 819         SecurityManager sm = getSecurityManager();
 820         if (sm != null) {
 821             sm.checkPermission(new PropertyPermission(key, "write"));
 822         }
 823 
 824         return (String) props.remove(key);
 825     }
 826 
 827     private static void checkKey(String key) {
 828         if (key == null) {
 829             throw new NullPointerException("key can't be null");
 830         }
 831         if (key.equals("")) {
 832             throw new IllegalArgumentException("key can't be empty");
 833         }
 834     }
 835 
 836     /**
 837      * Gets the value of the specified environment variable. An
 838      * environment variable is a system-dependent external named
 839      * value.
 840      *
 841      * <p>If a security manager exists, its
 842      * {@link SecurityManager#checkPermission checkPermission}
 843      * method is called with a
 844      * <code>{@link RuntimePermission}("getenv."+name)</code>
 845      * permission.  This may result in a {@link SecurityException}
 846      * being thrown.  If no exception is thrown the value of the
 847      * variable <code>name</code> is returned.
 848      *
 849      * <p><a name="EnvironmentVSSystemProperties"><i>System
 850      * properties</i> and <i>environment variables</i></a> are both
 851      * conceptually mappings between names and values.  Both
 852      * mechanisms can be used to pass user-defined information to a
 853      * Java process.  Environment variables have a more global effect,
 854      * because they are visible to all descendants of the process
 855      * which defines them, not just the immediate Java subprocess.
 856      * They can have subtly different semantics, such as case
 857      * insensitivity, on different operating systems.  For these
 858      * reasons, environment variables are more likely to have
 859      * unintended side effects.  It is best to use system properties
 860      * where possible.  Environment variables should be used when a
 861      * global effect is desired, or when an external system interface
 862      * requires an environment variable (such as <code>PATH</code>).
 863      *
 864      * <p>On UNIX systems the alphabetic case of <code>name</code> is
 865      * typically significant, while on Microsoft Windows systems it is
 866      * typically not.  For example, the expression
 867      * <code>System.getenv("FOO").equals(System.getenv("foo"))</code>
 868      * is likely to be true on Microsoft Windows.
 869      *
 870      * @param  name the name of the environment variable
 871      * @return the string value of the variable, or <code>null</code>
 872      *         if the variable is not defined in the system environment
 873      * @throws NullPointerException if <code>name</code> is <code>null</code>
 874      * @throws SecurityException
 875      *         if a security manager exists and its
 876      *         {@link SecurityManager#checkPermission checkPermission}
 877      *         method doesn't allow access to the environment variable
 878      *         <code>name</code>
 879      * @see    #getenv()
 880      * @see    ProcessBuilder#environment()
 881      */
 882     public static String getenv(String name) {
 883         SecurityManager sm = getSecurityManager();
 884         if (sm != null) {
 885             sm.checkPermission(new RuntimePermission("getenv."+name));
 886         }
 887 
 888         return ProcessEnvironment.getenv(name);
 889     }
 890 
 891 
 892     /**
 893      * Returns an unmodifiable string map view of the current system environment.
 894      * The environment is a system-dependent mapping from names to
 895      * values which is passed from parent to child processes.
 896      *
 897      * <p>If the system does not support environment variables, an
 898      * empty map is returned.
 899      *
 900      * <p>The returned map will never contain null keys or values.
 901      * Attempting to query the presence of a null key or value will
 902      * throw a {@link NullPointerException}.  Attempting to query
 903      * the presence of a key or value which is not of type
 904      * {@link String} will throw a {@link ClassCastException}.
 905      *
 906      * <p>The returned map and its collection views may not obey the
 907      * general contract of the {@link Object#equals} and
 908      * {@link Object#hashCode} methods.
 909      *
 910      * <p>The returned map is typically case-sensitive on all platforms.
 911      *
 912      * <p>If a security manager exists, its
 913      * {@link SecurityManager#checkPermission checkPermission}
 914      * method is called with a
 915      * <code>{@link RuntimePermission}("getenv.*")</code>
 916      * permission.  This may result in a {@link SecurityException} being
 917      * thrown.
 918      *
 919      * <p>When passing information to a Java subprocess,
 920      * <a href=#EnvironmentVSSystemProperties>system properties</a>
 921      * are generally preferred over environment variables.
 922      *
 923      * @return the environment as a map of variable names to values
 924      * @throws SecurityException
 925      *         if a security manager exists and its
 926      *         {@link SecurityManager#checkPermission checkPermission}
 927      *         method doesn't allow access to the process environment
 928      * @see    #getenv(String)
 929      * @see    ProcessBuilder#environment()
 930      * @since  1.5
 931      */
 932     public static java.util.Map<String,String> getenv() {
 933         SecurityManager sm = getSecurityManager();
 934         if (sm != null) {
 935             sm.checkPermission(new RuntimePermission("getenv.*"));
 936         }
 937 
 938         return ProcessEnvironment.getenv();
 939     }
 940 
 941     /**
 942      * Terminates the currently running Java Virtual Machine. The
 943      * argument serves as a status code; by convention, a nonzero status
 944      * code indicates abnormal termination.
 945      * <p>
 946      * This method calls the <code>exit</code> method in class
 947      * <code>Runtime</code>. This method never returns normally.
 948      * <p>
 949      * The call <code>System.exit(n)</code> is effectively equivalent to
 950      * the call:
 951      * <blockquote><pre>
 952      * Runtime.getRuntime().exit(n)
 953      * </pre></blockquote>
 954      *
 955      * @param      status   exit status.
 956      * @throws  SecurityException
 957      *        if a security manager exists and its <code>checkExit</code>
 958      *        method doesn't allow exit with the specified status.
 959      * @see        java.lang.Runtime#exit(int)
 960      */
 961     public static void exit(int status) {
 962         Runtime.getRuntime().exit(status);
 963     }
 964 
 965     /**
 966      * Runs the garbage collector.
 967      * <p>
 968      * Calling the <code>gc</code> method suggests that the Java Virtual
 969      * Machine expend effort toward recycling unused objects in order to
 970      * make the memory they currently occupy available for quick reuse.
 971      * When control returns from the method call, the Java Virtual
 972      * Machine has made a best effort to reclaim space from all discarded
 973      * objects.
 974      * <p>
 975      * The call <code>System.gc()</code> is effectively equivalent to the
 976      * call:
 977      * <blockquote><pre>
 978      * Runtime.getRuntime().gc()
 979      * </pre></blockquote>
 980      *
 981      * @see     java.lang.Runtime#gc()
 982      */
 983     public static void gc() {
 984         Runtime.getRuntime().gc();
 985     }
 986 
 987     /**
 988      * Runs the finalization methods of any objects pending finalization.
 989      * <p>
 990      * Calling this method suggests that the Java Virtual Machine expend
 991      * effort toward running the <code>finalize</code> methods of objects
 992      * that have been found to be discarded but whose <code>finalize</code>
 993      * methods have not yet been run. When control returns from the
 994      * method call, the Java Virtual Machine has made a best effort to
 995      * complete all outstanding finalizations.
 996      * <p>
 997      * The call <code>System.runFinalization()</code> is effectively
 998      * equivalent to the call:
 999      * <blockquote><pre>
1000      * Runtime.getRuntime().runFinalization()
1001      * </pre></blockquote>
1002      *
1003      * @see     java.lang.Runtime#runFinalization()
1004      */
1005     public static void runFinalization() {
1006         Runtime.getRuntime().runFinalization();
1007     }
1008 
1009     /**
1010      * Enable or disable finalization on exit; doing so specifies that the
1011      * finalizers of all objects that have finalizers that have not yet been
1012      * automatically invoked are to be run before the Java runtime exits.
1013      * By default, finalization on exit is disabled.
1014      *
1015      * <p>If there is a security manager,
1016      * its <code>checkExit</code> method is first called
1017      * with 0 as its argument to ensure the exit is allowed.
1018      * This could result in a SecurityException.
1019      *
1020      * @deprecated  This method is inherently unsafe.  It may result in
1021      *      finalizers being called on live objects while other threads are
1022      *      concurrently manipulating those objects, resulting in erratic
1023      *      behavior or deadlock.
1024      * @param value indicating enabling or disabling of finalization
1025      * @throws  SecurityException
1026      *        if a security manager exists and its <code>checkExit</code>
1027      *        method doesn't allow the exit.
1028      *
1029      * @see     java.lang.Runtime#exit(int)
1030      * @see     java.lang.Runtime#gc()
1031      * @see     java.lang.SecurityManager#checkExit(int)
1032      * @since   JDK1.1
1033      */
1034     @Deprecated
1035     public static void runFinalizersOnExit(boolean value) {
1036         Runtime.runFinalizersOnExit(value);
1037     }
1038 
1039     /**
1040      * Loads the native library specified by the filename argument.  The filename 
1041      * argument must be an absolute path name.
1042      *  
1043      * If the filename argument, when stripped of any platform-specific library 
1044      * prefix, path, and file extension, indicates a library whose name is L, 
1045      * and a native library called L is statically linked with the VM, then the 
1046      * JNI_OnLoad_L function exported by the library is invoked rather than 
1047      * attempting to load a dynamic library.  A filename matching the argument 
1048      * does not have to exist in the file system.   See the JNI Specification 
1049      * for more details.
1050      * 
1051      * Otherwise, the filename argument is mapped to a native library image in 
1052      * an implementation-dependent manner.
1053      * 
1054      * <p>
1055      * The call <code>System.load(name)</code> is effectively equivalent
1056      * to the call:
1057      * <blockquote><pre>
1058      * Runtime.getRuntime().load(name)
1059      * </pre></blockquote>
1060      *
1061      * @param      filename   the file to load.
1062      * @exception  SecurityException  if a security manager exists and its
1063      *             <code>checkLink</code> method doesn't allow
1064      *             loading of the specified dynamic library
1065      * @exception  UnsatisfiedLinkError  if either the filename is not an 
1066      *             absolute path name, the native library is not statically 
1067      *             linked with the VM, or the library cannot be mapped to 
1068      *             a native library image by the host system.
1069      * @exception  NullPointerException if <code>filename</code> is
1070      *             <code>null</code>
1071      * @see        java.lang.Runtime#load(java.lang.String)
1072      * @see        java.lang.SecurityManager#checkLink(java.lang.String)
1073      */
1074     public static void load(String filename) {
1075         Runtime.getRuntime().load0(getCallerClass(), filename);
1076     }
1077 
1078     /**
1079      * Loads the native library specified by the <code>libname</code> 
1080      * argument.  The <code>libname</code> argument must not contain any platform 
1081      * specific prefix, file extension or path. If a native library 
1082      * called <code>libname</code> is statically linked with the VM, then the 
1083      * JNI_OnLoad_<code>libname</code> function exported by the library is invoked. 
1084      * See the JNI Specification for more details.
1085      *  
1086      * Otherwise, the libname argument is loaded from a system library 
1087      * location and mapped to a native library image in an implementation-
1088      * dependent manner.
1089      * <p>
1090      * The call <code>System.loadLibrary(name)</code> is effectively
1091      * equivalent to the call
1092      * <blockquote><pre>
1093      * Runtime.getRuntime().loadLibrary(name)
1094      * </pre></blockquote>
1095      *
1096      * @param      libname   the name of the library.
1097      * @exception  SecurityException  if a security manager exists and its
1098      *             <code>checkLink</code> method doesn't allow
1099      *             loading of the specified dynamic library
1100      * @exception  UnsatisfiedLinkError if either the libname argument 
1101      *             contains a file path, the native library is not statically 
1102      *             linked with the VM,  or the library cannot be mapped to a 
1103      *             native library image by the host system.
1104      * @exception  NullPointerException if <code>libname</code> is
1105      *             <code>null</code>
1106      * @see        java.lang.Runtime#loadLibrary(java.lang.String)
1107      * @see        java.lang.SecurityManager#checkLink(java.lang.String)
1108      */
1109     public static void loadLibrary(String libname) {
1110         Runtime.getRuntime().loadLibrary0(getCallerClass(), libname);
1111     }
1112 
1113     /**
1114      * Maps a library name into a platform-specific string representing
1115      * a native library.
1116      *
1117      * @param      libname the name of the library.
1118      * @return     a platform-dependent native library name.
1119      * @exception  NullPointerException if <code>libname</code> is
1120      *             <code>null</code>
1121      * @see        java.lang.System#loadLibrary(java.lang.String)
1122      * @see        java.lang.ClassLoader#findLibrary(java.lang.String)
1123      * @since      1.2
1124      */
1125     public static native String mapLibraryName(String libname);
1126 
1127     /**
1128      * Create PrintStream for stdout/err based on encoding.
1129      */
1130     private static PrintStream newPrintStream(FileOutputStream fos, String enc) {
1131        if (enc != null) {
1132             try {
1133                 return new PrintStream(new BufferedOutputStream(fos, 128), true, enc);
1134             } catch (UnsupportedEncodingException uee) {}
1135         }
1136         return new PrintStream(new BufferedOutputStream(fos, 128), true);
1137     }
1138 
1139 
1140     /**
1141      * Initialize the system class.  Called after thread initialization.
1142      */
1143     private static void initializeSystemClass() {
1144 
1145         // VM might invoke JNU_NewStringPlatform() to set those encoding
1146         // sensitive properties (user.home, user.name, boot.class.path, etc.)
1147         // during "props" initialization, in which it may need access, via
1148         // System.getProperty(), to the related system encoding property that
1149         // have been initialized (put into "props") at early stage of the
1150         // initialization. So make sure the "props" is available at the
1151         // very beginning of the initialization and all system properties to
1152         // be put into it directly.
1153         props = new Properties();
1154         initProperties(props);  // initialized by the VM
1155 
1156         // There are certain system configurations that may be controlled by
1157         // VM options such as the maximum amount of direct memory and
1158         // Integer cache size used to support the object identity semantics
1159         // of autoboxing.  Typically, the library will obtain these values
1160         // from the properties set by the VM.  If the properties are for
1161         // internal implementation use only, these properties should be
1162         // removed from the system properties.
1163         //
1164         // See java.lang.Integer.IntegerCache and the
1165         // sun.misc.VM.saveAndRemoveProperties method for example.
1166         //
1167         // Save a private copy of the system properties object that
1168         // can only be accessed by the internal implementation.  Remove
1169         // certain system properties that are not intended for public access.
1170         sun.misc.VM.saveAndRemoveProperties(props);
1171 
1172 
1173         lineSeparator = props.getProperty("line.separator");
1174         sun.misc.Version.init();
1175 
1176         FileInputStream fdIn = new FileInputStream(FileDescriptor.in);
1177         FileOutputStream fdOut = new FileOutputStream(FileDescriptor.out);
1178         FileOutputStream fdErr = new FileOutputStream(FileDescriptor.err);
1179         setIn0(new BufferedInputStream(fdIn));
1180         setOut0(newPrintStream(fdOut, props.getProperty("sun.stdout.encoding")));
1181         setErr0(newPrintStream(fdErr, props.getProperty("sun.stderr.encoding")));
1182 
1183         // Load the zip library now in order to keep java.util.zip.ZipFile
1184         // from trying to use itself to load this library later.
1185         loadLibrary("zip");
1186 
1187         // Setup Java signal handlers for HUP, TERM, and INT (where available).
1188         Terminator.setup();
1189 
1190         // Initialize any miscellenous operating system settings that need to be
1191         // set for the class libraries. Currently this is no-op everywhere except
1192         // for Windows where the process-wide error mode is set before the java.io
1193         // classes are used.
1194         sun.misc.VM.initializeOSEnvironment();
1195 
1196         // The main thread is not added to its thread group in the same
1197         // way as other threads; we must do it ourselves here.
1198         Thread current = Thread.currentThread();
1199         current.getThreadGroup().add(current);
1200 
1201         // register shared secrets
1202         setJavaLangAccess();
1203 
1204         // Subsystems that are invoked during initialization can invoke
1205         // sun.misc.VM.isBooted() in order to avoid doing things that should
1206         // wait until the application class loader has been set up.
1207         // IMPORTANT: Ensure that this remains the last initialization action!
1208         sun.misc.VM.booted();
1209     }
1210 
1211     private static void setJavaLangAccess() {
1212         // Allow privileged classes outside of java.lang
1213         sun.misc.SharedSecrets.setJavaLangAccess(new sun.misc.JavaLangAccess(){
1214             public sun.reflect.ConstantPool getConstantPool(Class<?> klass) {
1215                 return klass.getConstantPool();
1216             }
1217             public void setAnnotationType(Class<?> klass, AnnotationType type) {
1218                 klass.setAnnotationType(type);
1219             }
1220             public AnnotationType getAnnotationType(Class<?> klass) {
1221                 return klass.getAnnotationType();
1222             }
1223             public byte[] getRawClassTypeAnnotations(Class<?> klass) {
1224                 return klass.getRawTypeAnnotations();
1225             }
1226             public byte[] getRawExecutableTypeAnnotations(Executable executable) {
1227                 return Class.getExecutableTypeAnnotationBytes(executable);
1228             }
1229             public <E extends Enum<E>>
1230                     E[] getEnumConstantsShared(Class<E> klass) {
1231                 return klass.getEnumConstantsShared();
1232             }
1233             public void blockedOn(Thread t, Interruptible b) {
1234                 t.blockedOn(b);
1235             }
1236             public void registerShutdownHook(int slot, boolean registerShutdownInProgress, Runnable hook) {
1237                 Shutdown.add(slot, registerShutdownInProgress, hook);
1238             }
1239             public int getStackTraceDepth(Throwable t) {
1240                 return t.getStackTraceDepth();
1241             }
1242             public StackTraceElement getStackTraceElement(Throwable t, int i) {
1243                 return t.getStackTraceElement(i);
1244             }
1245         });
1246     }
1247 
1248     /* returns the class of the caller. */
1249     static Class<?> getCallerClass() {
1250         // NOTE use of more generic Reflection.getCallerClass()
1251         return Reflection.getCallerClass(3);
1252     }
1253 }
--- EOF ---