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