/*
- * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 
 package java.lang;
 
 import java.io.*;
+import java.math.BigInteger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.List;
+import java.util.Optional;
 import java.util.StringTokenizer;
-import sun.reflect.CallerSensitive;
-import sun.reflect.Reflection;
+
+import jdk.internal.access.SharedSecrets;
+import jdk.internal.reflect.CallerSensitive;
+import jdk.internal.reflect.Reflection;
 
 /**
  * Every Java application has a single instance of class
- * <code>Runtime</code> that allows the application to interface with
+ * {@code Runtime} that allows the application to interface with
  * the environment in which the application is running. The current
- * runtime can be obtained from the <code>getRuntime</code> method.
+ * runtime can be obtained from the {@code getRuntime} method.
  * <p>
  * An application cannot create its own instance of this class.
  *
  * @author  unascribed
  * @see     java.lang.Runtime#getRuntime()
- * @since   JDK1.0
+ * @since   1.0
  */
 
 public class Runtime {
-    private static Runtime currentRuntime = new Runtime();
+    private static final Runtime currentRuntime = new Runtime();
+
+    private static Version version;
 
     /**
      * Returns the runtime object associated with the current Java application.
-     * Most of the methods of class <code>Runtime</code> are instance
+     * Most of the methods of class {@code Runtime} are instance
      * methods and must be invoked with respect to the current runtime object.
      *
-     * @return  the <code>Runtime</code> object associated with the current
+     * @return  the {@code Runtime} object associated with the current
      *          Java application.
      */
     public static Runtime getRuntime() {
         return currentRuntime;
     }
 
     /** Don't let anyone else instantiate this class */
     private Runtime() {}
 
     /**
      * Terminates the currently running Java virtual machine by initiating its
      * shutdown sequence.  This method never returns normally.  The argument
      * serves as a status code; by convention, a nonzero status code indicates
      * abnormal termination.
      *
-     * <p> The virtual machine's shutdown sequence consists of two phases.  In
-     * the first phase all registered {@link #addShutdownHook shutdown hooks},
-     * if any, are started in some unspecified order and allowed to run
-     * concurrently until they finish.  In the second phase all uninvoked
-     * finalizers are run if {@link #runFinalizersOnExit finalization-on-exit}
-     * has been enabled.  Once this is done the virtual machine {@link #halt
-     * halts}.
+     * <p> All registered {@linkplain #addShutdownHook shutdown hooks}, if any,
+     * are started in some unspecified order and allowed to run concurrently
+     * until they finish.  Once this is done the virtual machine
+     * {@linkplain #halt halts}.
      *
-     * <p> If this method is invoked after the virtual machine has begun its
-     * shutdown sequence then if shutdown hooks are being run this method will
-     * block indefinitely.  If shutdown hooks have already been run and on-exit
-     * finalization has been enabled then this method halts the virtual machine
-     * with the given status code if the status is nonzero; otherwise, it
+     * <p> If this method is invoked after all shutdown hooks have already
+     * been run and the status is nonzero then this method halts the
+     * virtual machine with the given status code. Otherwise, this method
      * blocks indefinitely.
      *
-     * <p> The <tt>{@link System#exit(int) System.exit}</tt> method is the
-     * conventional and convenient means of invoking this method. <p>
+     * <p> The {@link System#exit(int) System.exit} method is the
+     * conventional and convenient means of invoking this method.
      *
      * @param  status
      *         Termination status.  By convention, a nonzero status code
      *         indicates abnormal termination.
      *
      * @throws SecurityException
-     *         If a security manager is present and its <tt>{@link
-     *         SecurityManager#checkExit checkExit}</tt> method does not permit
+     *         If a security manager is present and its
+     *         {@link SecurityManager#checkExit checkExit} method does not permit
      *         exiting with the specified status
      *
      * @see java.lang.SecurityException
      * @see java.lang.SecurityManager#checkExit(int)
      * @see #addShutdownHook
      * @see #removeShutdownHook
-     * @see #runFinalizersOnExit
      * @see #halt(int)
      */
     public void exit(int status) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkExit(status);
         }
         Shutdown.exit(status);
     }
 
     /**
      * Registers a new virtual-machine shutdown hook.
      *
      * <p> The Java virtual machine <i>shuts down</i> in response to two kinds
      * of events:
      *
      *   <ul>
      *
      *   <li> The program <i>exits</i> normally, when the last non-daemon
-     *   thread exits or when the <tt>{@link #exit exit}</tt> (equivalently,
+     *   thread exits or when the {@link #exit exit} (equivalently,
      *   {@link System#exit(int) System.exit}) method is invoked, or
      *
      *   <li> The virtual machine is <i>terminated</i> in response to a
-     *   user interrupt, such as typing <tt>^C</tt>, or a system-wide event,
+     *   user interrupt, such as typing {@code ^C}, or a system-wide event,
      *   such as user logoff or system shutdown.
      *
      *   </ul>
      *
      * <p> A <i>shutdown hook</i> is simply an initialized but unstarted
      * thread.  When the virtual machine begins its shutdown sequence it will
      * start all registered shutdown hooks in some unspecified order and let
      * them run concurrently.  When all the hooks have finished it will then
-     * run all uninvoked finalizers if finalization-on-exit has been enabled.
-     * Finally, the virtual machine will halt.  Note that daemon threads will
-     * continue to run during the shutdown sequence, as will non-daemon threads
-     * if shutdown was initiated by invoking the <tt>{@link #exit exit}</tt>
-     * method.
+     * halt. Note that daemon threads will continue to run during the shutdown
+     * sequence, as will non-daemon threads if shutdown was initiated by
+     * invoking the {@link #exit exit} method.
      *
      * <p> Once the shutdown sequence has begun it can be stopped only by
-     * invoking the <tt>{@link #halt halt}</tt> method, which forcibly
+     * invoking the {@link #halt halt} method, which forcibly
      * terminates the virtual machine.
      *
      * <p> Once the shutdown sequence has begun it is impossible to register a
      * new shutdown hook or de-register a previously-registered hook.
      * Attempting either of these operations will cause an
-     * <tt>{@link IllegalStateException}</tt> to be thrown.
+     * {@link IllegalStateException} to be thrown.
      *
      * <p> Shutdown hooks run at a delicate time in the life cycle of a virtual
      * machine and should therefore be coded defensively.  They should, in
      * particular, be written to be thread-safe and to avoid deadlocks insofar
      * as possible.  They should also not rely blindly upon services that may
      * have registered their own shutdown hooks and therefore may themselves in
      * the process of shutting down.  Attempts to use other thread-based
      * services such as the AWT event-dispatch thread, for example, may lead to
      * deadlocks.
      *
      * <p> Shutdown hooks should also finish their work quickly.  When a
-     * program invokes <tt>{@link #exit exit}</tt> the expectation is
+     * program invokes {@link #exit exit} the expectation is
      * that the virtual machine will promptly shut down and exit.  When the
      * virtual machine is terminated due to user logoff or system shutdown the
      * underlying operating system may only allow a fixed amount of time in
      * which to shut down and exit.  It is therefore inadvisable to attempt any
      * user interaction or to perform a long-running computation in a shutdown
      * hook.
      *
      * <p> Uncaught exceptions are handled in shutdown hooks just as in any
-     * other thread, by invoking the <tt>{@link ThreadGroup#uncaughtException
-     * uncaughtException}</tt> method of the thread's <tt>{@link
-     * ThreadGroup}</tt> object.  The default implementation of this method
-     * prints the exception's stack trace to <tt>{@link System#err}</tt> and
+     * other thread, by invoking the
+     * {@link ThreadGroup#uncaughtException uncaughtException} method of the
+     * thread's {@link ThreadGroup} object. The default implementation of this
+     * method prints the exception's stack trace to {@link System#err} and
      * terminates the thread; it does not cause the virtual machine to exit or
      * halt.
      *
      * <p> In rare circumstances the virtual machine may <i>abort</i>, that is,
      * stop running without shutting down cleanly.  This occurs when the
      * virtual machine is terminated externally, for example with the
-     * <tt>SIGKILL</tt> signal on Unix or the <tt>TerminateProcess</tt> call on
+     * {@code SIGKILL} signal on Unix or the {@code TerminateProcess} call on
      * Microsoft Windows.  The virtual machine may also abort if a native
      * method goes awry by, for example, corrupting internal data structures or
      * attempting to access nonexistent memory.  If the virtual machine aborts
      * then no guarantee can be made about whether or not any shutdown hooks
-     * will be run. <p>
+     * will be run.
      *
      * @param   hook
-     *          An initialized but unstarted <tt>{@link Thread}</tt> object
+     *          An initialized but unstarted {@link Thread} object
      *
      * @throws  IllegalArgumentException
      *          If the specified hook has already been registered,
      *          or if it can be determined that the hook is already running or
      *          has already been run
      *
      * @throws  IllegalStateException
      *          If the virtual machine is already in the process
      *          of shutting down
      *
      * @throws  SecurityException
      *          If a security manager is present and it denies
-     *          <tt>{@link RuntimePermission}("shutdownHooks")</tt>
+     *          {@link RuntimePermission}("shutdownHooks")
      *
      * @see #removeShutdownHook
      * @see #halt(int)
      * @see #exit(int)
      * @since 1.3
      */
     public void addShutdownHook(Thread hook) {
         SecurityManager sm = System.getSecurityManager();
         if (sm != null) {
             sm.checkPermission(new RuntimePermission("shutdownHooks"));
         }
         ApplicationShutdownHooks.add(hook);
     }
 
     /**
-     * De-registers a previously-registered virtual-machine shutdown hook. <p>
+     * De-registers a previously-registered virtual-machine shutdown hook.
      *
      * @param hook the hook to remove
-     * @return <tt>true</tt> if the specified hook had previously been
-     * registered and was successfully de-registered, <tt>false</tt>
+     * @return {@code true} if the specified hook had previously been
+     * registered and was successfully de-registered, {@code false}
      * otherwise.
      *
      * @throws  IllegalStateException
      *          If the virtual machine is already in the process of shutting
      *          down
      *
      * @throws  SecurityException
      *          If a security manager is present and it denies
-     *          <tt>{@link RuntimePermission}("shutdownHooks")</tt>
+     *          {@link RuntimePermission}("shutdownHooks")
      *
      * @see #addShutdownHook
      * @see #exit(int)
      * @since 1.3
      */
     public boolean removeShutdownHook(Thread hook) {
         SecurityManager sm = System.getSecurityManager();
         if (sm != null) {
             sm.checkPermission(new RuntimePermission("shutdownHooks"));
         }
         return ApplicationShutdownHooks.remove(hook);
     }
 
     /**
      * Forcibly terminates the currently running Java virtual machine.  This
      * method never returns normally.
      *
      * <p> This method should be used with extreme caution.  Unlike the
-     * <tt>{@link #exit exit}</tt> method, this method does not cause shutdown
-     * hooks to be started and does not run uninvoked finalizers if
-     * finalization-on-exit has been enabled.  If the shutdown sequence has
-     * already been initiated then this method does not wait for any running
-     * shutdown hooks or finalizers to finish their work. <p>
+     * {@link #exit exit} method, this method does not cause shutdown
+     * hooks to be started.  If the shutdown sequence has already been
+     * initiated then this method does not wait for any running
+     * shutdown hooks to finish their work.
      *
      * @param  status
-     *         Termination status.  By convention, a nonzero status code
-     *         indicates abnormal termination.  If the <tt>{@link Runtime#exit
-     *         exit}</tt> (equivalently, <tt>{@link System#exit(int)
-     *         System.exit}</tt>) method has already been invoked then this
-     *         status code will override the status code passed to that method.
+     *         Termination status. By convention, a nonzero status code
+     *         indicates abnormal termination. If the {@link Runtime#exit exit}
+     *         (equivalently, {@link System#exit(int) System.exit}) method
+     *         has already been invoked then this status code
+     *         will override the status code passed to that method.
      *
      * @throws SecurityException
-     *         If a security manager is present and its <tt>{@link
-     *         SecurityManager#checkExit checkExit}</tt> method does not permit
-     *         an exit with the specified status
+     *         If a security manager is present and its
+     *         {@link SecurityManager#checkExit checkExit} method
+     *         does not permit an exit with the specified status
      *
      * @see #exit
      * @see #addShutdownHook
      * @see #removeShutdownHook
      * @since 1.3
      */
     public void halt(int status) {
         SecurityManager sm = System.getSecurityManager();
         if (sm != null) {
             sm.checkExit(status);
         }
         Shutdown.beforeHalt();
         Shutdown.halt(status);
     }
 
     /**
-     * Enable or disable finalization on exit; doing so specifies that the
-     * finalizers of all objects that have finalizers that have not yet been
-     * automatically invoked are to be run before the Java runtime exits.
-     * By default, finalization on exit is disabled.
-     *
-     * <p>If there is a security manager,
-     * its <code>checkExit</code> method is first called
-     * with 0 as its argument to ensure the exit is allowed.
-     * This could result in a SecurityException.
-     *
-     * @param value true to enable finalization on exit, false to disable
-     * @deprecated  This method is inherently unsafe.  It may result in
-     *      finalizers being called on live objects while other threads are
-     *      concurrently manipulating those objects, resulting in erratic
-     *      behavior or deadlock.
-     *
-     * @throws  SecurityException
-     *        if a security manager exists and its <code>checkExit</code>
-     *        method doesn't allow the exit.
-     *
-     * @see     java.lang.Runtime#exit(int)
-     * @see     java.lang.Runtime#gc()
-     * @see     java.lang.SecurityManager#checkExit(int)
-     * @since   JDK1.1
-     */
-    @Deprecated
-    public static void runFinalizersOnExit(boolean value) {
-        SecurityManager security = System.getSecurityManager();
-        if (security != null) {
-            try {
-                security.checkExit(0);
-            } catch (SecurityException e) {
-                throw new SecurityException("runFinalizersOnExit");
-            }
-        }
-        Shutdown.setRunFinalizersOnExit(value);
-    }
-
-    /**
      * Executes the specified string command in a separate process.
      *
      * <p>This is a convenience method.  An invocation of the form
-     * <tt>exec(command)</tt>
+     * {@code exec(command)}
      * behaves in exactly the same way as the invocation
-     * <tt>{@link #exec(String, String[], File) exec}(command, null, null)</tt>.
+     * {@link #exec(String, String[], File) exec}{@code (command, null, null)}.
      *
      * @param   command   a specified system command.
      *
      * @return  A new {@link Process} object for managing the subprocess
      *
      * @throws  SecurityException
      *          If a security manager exists and its
      *          {@link SecurityManager#checkExec checkExec}
      *          method doesn't allow creation of the subprocess
      *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  NullPointerException
-     *          If <code>command</code> is <code>null</code>
+     *          If {@code command} is {@code null}
      *
      * @throws  IllegalArgumentException
-     *          If <code>command</code> is empty
+     *          If {@code command} is empty
      *
      * @see     #exec(String[], String[], File)
      * @see     ProcessBuilder
      */
     public Process exec(String command) throws IOException {
         return exec(command, null, null);
     }
 
     /**
      * Executes the specified string command in a separate process with the
      * specified environment.
      *
      * <p>This is a convenience method.  An invocation of the form
-     * <tt>exec(command, envp)</tt>
+     * {@code exec(command, envp)}
      * behaves in exactly the same way as the invocation
-     * <tt>{@link #exec(String, String[], File) exec}(command, envp, null)</tt>.
+     * {@link #exec(String, String[], File) exec}{@code (command, envp, null)}.
      *
      * @param   command   a specified system command.
      *
      * @param   envp      array of strings, each element of which
      *                    has environment variable settings in the format
      *                    <i>name</i>=<i>value</i>, or
-     *                    <tt>null</tt> if the subprocess should inherit
+     *                    {@code null} if the subprocess should inherit
      *                    the environment of the current process.
      *
      * @return  A new {@link Process} object for managing the subprocess
      *
      * @throws  SecurityException
      *          If a security manager exists and its
      *          {@link SecurityManager#checkExec checkExec}
      *          method doesn't allow creation of the subprocess
      *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  NullPointerException
-     *          If <code>command</code> is <code>null</code>,
-     *          or one of the elements of <code>envp</code> is <code>null</code>
+     *          If {@code command} is {@code null},
+     *          or one of the elements of {@code envp} is {@code null}
      *
      * @throws  IllegalArgumentException
-     *          If <code>command</code> is empty
+     *          If {@code command} is empty
      *
      * @see     #exec(String[], String[], File)
      * @see     ProcessBuilder
      */
     public Process exec(String command, String[] envp) throws IOException {
         return exec(command, envp, null);
     }
 
     /**
      * Executes the specified string command in a separate process with the
      * specified environment and working directory.
      *
      * <p>This is a convenience method.  An invocation of the form
-     * <tt>exec(command, envp, dir)</tt>
+     * {@code exec(command, envp, dir)}
      * behaves in exactly the same way as the invocation
-     * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, envp, dir)</tt>,
-     * where <code>cmdarray</code> is an array of all the tokens in
-     * <code>command</code>.
+     * {@link #exec(String[], String[], File) exec}{@code (cmdarray, envp, dir)},
+     * where {@code cmdarray} is an array of all the tokens in
+     * {@code command}.
      *
-     * <p>More precisely, the <code>command</code> string is broken
+     * <p>More precisely, the {@code command} string is broken
      * into tokens using a {@link StringTokenizer} created by the call
-     * <code>new {@link StringTokenizer}(command)</code> with no
+     * {@code new {@link StringTokenizer}(command)} with no
      * further modification of the character categories.  The tokens
      * produced by the tokenizer are then placed in the new string
-     * array <code>cmdarray</code>, in the same order.
+     * array {@code cmdarray}, in the same order.
      *
      * @param   command   a specified system command.
      *
      * @param   envp      array of strings, each element of which
      *                    has environment variable settings in the format
      *                    <i>name</i>=<i>value</i>, or
-     *                    <tt>null</tt> if the subprocess should inherit
+     *                    {@code null} if the subprocess should inherit
      *                    the environment of the current process.
      *
      * @param   dir       the working directory of the subprocess, or
-     *                    <tt>null</tt> if the subprocess should inherit
+     *                    {@code null} if the subprocess should inherit
      *                    the working directory of the current process.
      *
      * @return  A new {@link Process} object for managing the subprocess
      *
      * @throws  SecurityException
      *          If a security manager exists and its
      *          {@link SecurityManager#checkExec checkExec}
      *          method doesn't allow creation of the subprocess
      *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  NullPointerException
-     *          If <code>command</code> is <code>null</code>,
-     *          or one of the elements of <code>envp</code> is <code>null</code>
+     *          If {@code command} is {@code null},
+     *          or one of the elements of {@code envp} is {@code null}
      *
      * @throws  IllegalArgumentException
-     *          If <code>command</code> is empty
+     *          If {@code command} is empty
      *
      * @see     ProcessBuilder
      * @since 1.3
      */
     public Process exec(String command, String[] envp, File dir)
         throws IOException {
-        if (command.length() == 0)
+        if (command.isEmpty())
             throw new IllegalArgumentException("Empty command");
 
         StringTokenizer st = new StringTokenizer(command);
         String[] cmdarray = new String[st.countTokens()];
         for (int i = 0; st.hasMoreTokens(); i++)
             cmdarray[i] = st.nextToken();
         return exec(cmdarray, envp, dir);
     }
 
     /**
      * Executes the specified command and arguments in a separate process.
      *
      * <p>This is a convenience method.  An invocation of the form
-     * <tt>exec(cmdarray)</tt>
+     * {@code exec(cmdarray)}
      * behaves in exactly the same way as the invocation
-     * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, null, null)</tt>.
+     * {@link #exec(String[], String[], File) exec}{@code (cmdarray, null, null)}.
      *
      * @param   cmdarray  array containing the command to call and
      *                    its arguments.
      *
      * @return  A new {@link Process} object for managing the subprocess
      *
      * @throws  SecurityException
      *          If a security manager exists and its
      *          {@link SecurityManager#checkExec checkExec}
      *          method doesn't allow creation of the subprocess
      *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  NullPointerException
-     *          If <code>cmdarray</code> is <code>null</code>,
-     *          or one of the elements of <code>cmdarray</code> is <code>null</code>
+     *          If {@code cmdarray} is {@code null},
+     *          or one of the elements of {@code cmdarray} is {@code null}
      *
      * @throws  IndexOutOfBoundsException
-     *          If <code>cmdarray</code> is an empty array
-     *          (has length <code>0</code>)
+     *          If {@code cmdarray} is an empty array
+     *          (has length {@code 0})
      *
      * @see     ProcessBuilder
      */
     public Process exec(String cmdarray[]) throws IOException {
         return exec(cmdarray, null, null);
     }
 
     /**
      * Executes the specified command and arguments in a separate process
      * with the specified environment.
      *
      * <p>This is a convenience method.  An invocation of the form
-     * <tt>exec(cmdarray, envp)</tt>
+     * {@code exec(cmdarray, envp)}
      * behaves in exactly the same way as the invocation
-     * <tt>{@link #exec(String[], String[], File) exec}(cmdarray, envp, null)</tt>.
+     * {@link #exec(String[], String[], File) exec}{@code (cmdarray, envp, null)}.
      *
      * @param   cmdarray  array containing the command to call and
      *                    its arguments.
      *
      * @param   envp      array of strings, each element of which
      *                    has environment variable settings in the format
      *                    <i>name</i>=<i>value</i>, or
-     *                    <tt>null</tt> if the subprocess should inherit
+     *                    {@code null} if the subprocess should inherit
      *                    the environment of the current process.
      *
      * @return  A new {@link Process} object for managing the subprocess
      *
      * @throws  SecurityException
      *          If a security manager exists and its
      *          {@link SecurityManager#checkExec checkExec}
      *          method doesn't allow creation of the subprocess
      *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  NullPointerException
-     *          If <code>cmdarray</code> is <code>null</code>,
-     *          or one of the elements of <code>cmdarray</code> is <code>null</code>,
-     *          or one of the elements of <code>envp</code> is <code>null</code>
+     *          If {@code cmdarray} is {@code null},
+     *          or one of the elements of {@code cmdarray} is {@code null},
+     *          or one of the elements of {@code envp} is {@code null}
      *
      * @throws  IndexOutOfBoundsException
-     *          If <code>cmdarray</code> is an empty array
-     *          (has length <code>0</code>)
+     *          If {@code cmdarray} is an empty array
+     *          (has length {@code 0})
      *
      * @see     ProcessBuilder
      */
     public Process exec(String[] cmdarray, String[] envp) throws IOException {
         return exec(cmdarray, envp, null);
     }
 
 
     /**
      * Executes the specified command and arguments in a separate process with
      * the specified environment and working directory.
      *
-     * <p>Given an array of strings <code>cmdarray</code>, representing the
-     * tokens of a command line, and an array of strings <code>envp</code>,
+     * <p>Given an array of strings {@code cmdarray}, representing the
+     * tokens of a command line, and an array of strings {@code envp},
      * representing "environment" variable settings, this method creates
      * a new process in which to execute the specified command.
      *
-     * <p>This method checks that <code>cmdarray</code> is a valid operating
+     * <p>This method checks that {@code cmdarray} is a valid operating
      * system command.  Which commands are valid is system-dependent,
      * but at the very least the command must be a non-empty list of
      * non-null strings.
      *
-     * <p>If <tt>envp</tt> is <tt>null</tt>, the subprocess inherits the
+     * <p>If {@code envp} is {@code null}, the subprocess inherits the
      * environment settings of the current process.
      *
      * <p>A minimal set of system dependent environment variables may
      * be required to start a process on some operating systems.
      * As a result, the subprocess may inherit additional environment variable
      * settings beyond those in the specified environment.
      *
      * <p>{@link ProcessBuilder#start()} is now the preferred way to
      * start a process with a modified environment.
      *
-     * <p>The working directory of the new subprocess is specified by <tt>dir</tt>.
-     * If <tt>dir</tt> is <tt>null</tt>, the subprocess inherits the
+     * <p>The working directory of the new subprocess is specified by {@code dir}.
+     * If {@code dir} is {@code null}, the subprocess inherits the
      * current working directory of the current process.
      *
      * <p>If a security manager exists, its
      * {@link SecurityManager#checkExec checkExec}
      * method is invoked with the first component of the array
-     * <code>cmdarray</code> as its argument. This may result in a
+     * {@code cmdarray} as its argument. This may result in a
      * {@link SecurityException} being thrown.
      *
      * <p>Starting an operating system process is highly system-dependent.
      * Among the many things that can go wrong are:
      * <ul>
      * <li>The operating system program file was not found.
      * <li>Access to the program file was denied.
      * <li>The working directory does not exist.
      * </ul>
      *
      * <p>In such cases an exception will be thrown.  The exact nature
      * of the exception is system-dependent, but it will always be a
      * subclass of {@link IOException}.
      *
+     * <p>If the operating system does not support the creation of
+     * processes, an {@link UnsupportedOperationException} will be thrown.
+     *
      *
      * @param   cmdarray  array containing the command to call and
      *                    its arguments.
      *
      * @param   envp      array of strings, each element of which
      *                    has environment variable settings in the format
      *                    <i>name</i>=<i>value</i>, or
-     *                    <tt>null</tt> if the subprocess should inherit
+     *                    {@code null} if the subprocess should inherit
      *                    the environment of the current process.
      *
      * @param   dir       the working directory of the subprocess, or
-     *                    <tt>null</tt> if the subprocess should inherit
+     *                    {@code null} if the subprocess should inherit
      *                    the working directory of the current process.
      *
      * @return  A new {@link Process} object for managing the subprocess
      *
      * @throws  SecurityException
      *          If a security manager exists and its
      *          {@link SecurityManager#checkExec checkExec}
      *          method doesn't allow creation of the subprocess
      *
+     * @throws  UnsupportedOperationException
+     *          If the operating system does not support the creation of processes.
+     *
      * @throws  IOException
      *          If an I/O error occurs
      *
      * @throws  NullPointerException
-     *          If <code>cmdarray</code> is <code>null</code>,
-     *          or one of the elements of <code>cmdarray</code> is <code>null</code>,
-     *          or one of the elements of <code>envp</code> is <code>null</code>
+     *          If {@code cmdarray} is {@code null},
+     *          or one of the elements of {@code cmdarray} is {@code null},
+     *          or one of the elements of {@code envp} is {@code null}
      *
      * @throws  IndexOutOfBoundsException
-     *          If <code>cmdarray</code> is an empty array
-     *          (has length <code>0</code>)
+     *          If {@code cmdarray} is an empty array
+     *          (has length {@code 0})
      *
      * @see     ProcessBuilder
      * @since 1.3
      */
     public Process exec(String[] cmdarray, String[] envp, File dir)
         throws IOException {
         return new ProcessBuilder(cmdarray)
             .environment(envp)
             .directory(dir)
             .start();
     }
 
     /**
      * Returns the number of processors available to the Java virtual machine.
      *
      * <p> This value may change during a particular invocation of the virtual
      * machine.  Applications that are sensitive to the number of available
      * processors should therefore occasionally poll this property and adjust
      * their resource usage appropriately. </p>
      *
      * @return  the maximum number of processors available to the virtual
      *          machine; never smaller than one
      * @since 1.4
      */
     public native int availableProcessors();
 
     /**
      * Returns the amount of free memory in the Java Virtual Machine.
      * Calling the
-     * <code>gc</code> method may result in increasing the value returned
-     * by <code>freeMemory.</code>
+     * {@code gc} method may result in increasing the value returned
+     * by {@code freeMemory.}
      *
      * @return  an approximation to the total amount of memory currently
      *          available for future allocated objects, measured in bytes.
      */
     public native long freeMemory();
 
     /**
      * Returns the total amount of memory in the Java virtual machine.
      * The value returned by this method may vary over time, depending on
      * the host environment.
      * <p>
      * Note that the amount of memory required to hold an object of any
      * given type may be implementation-dependent.
      *
      * @return  the total amount of memory currently available for current
      *          and future objects, measured in bytes.
      */
     public native long totalMemory();
 
     /**
-     * Returns the maximum amount of memory that the Java virtual machine will
-     * attempt to use.  If there is no inherent limit then the value {@link
-     * java.lang.Long#MAX_VALUE} will be returned.
+     * Returns the maximum amount of memory that the Java virtual machine
+     * will attempt to use.  If there is no inherent limit then the value
+     * {@link java.lang.Long#MAX_VALUE} will be returned.
      *
      * @return  the maximum amount of memory that the virtual machine will
      *          attempt to use, measured in bytes
      * @since 1.4
      */
     public native long maxMemory();
 
     /**
      * Runs the garbage collector.
      * Calling this method suggests that the Java virtual machine expend
      * effort toward recycling unused objects in order to make the memory
      * they currently occupy available for quick reuse. When control
      * returns from the method call, the virtual machine has made
      * its best effort to recycle all discarded objects.
      * <p>
-     * The name <code>gc</code> stands for "garbage
+     * The name {@code gc} stands for "garbage
      * collector". The virtual machine performs this recycling
      * process automatically as needed, in a separate thread, even if the
-     * <code>gc</code> method is not invoked explicitly.
+     * {@code gc} method is not invoked explicitly.
      * <p>
      * The method {@link System#gc()} is the conventional and convenient
      * means of invoking this method.
      */
     public native void gc();
 
-    /* Wormhole for calling java.lang.ref.Finalizer.runFinalization */
-    private static native void runFinalization0();
-
     /**
      * Runs the finalization methods of any objects pending finalization.
      * Calling this method suggests that the Java virtual machine expend
-     * effort toward running the <code>finalize</code> methods of objects
-     * that have been found to be discarded but whose <code>finalize</code>
+     * effort toward running the {@code finalize} methods of objects
+     * that have been found to be discarded but whose {@code finalize}
      * methods have not yet been run. When control returns from the
      * method call, the virtual machine has made a best effort to
      * complete all outstanding finalizations.
      * <p>
      * The virtual machine performs the finalization process
      * automatically as needed, in a separate thread, if the
-     * <code>runFinalization</code> method is not invoked explicitly.
+     * {@code runFinalization} method is not invoked explicitly.
      * <p>
      * The method {@link System#runFinalization()} is the conventional
      * and convenient means of invoking this method.
      *
      * @see     java.lang.Object#finalize()
      */
     public void runFinalization() {
-        runFinalization0();
+        SharedSecrets.getJavaLangRefAccess().runFinalization();
     }
 
     /**
-     * Enables/Disables tracing of instructions.
-     * If the <code>boolean</code> argument is <code>true</code>, this
-     * method suggests that the Java virtual machine emit debugging
-     * information for each instruction in the virtual machine as it
-     * is executed. The format of this information, and the file or other
-     * output stream to which it is emitted, depends on the host environment.
-     * The virtual machine may ignore this request if it does not support
-     * this feature. The destination of the trace output is system
-     * dependent.
-     * <p>
-     * If the <code>boolean</code> argument is <code>false</code>, this
-     * method causes the virtual machine to stop performing the
-     * detailed instruction trace it is performing.
+     * Not implemented, does nothing.
      *
-     * @param   on   <code>true</code> to enable instruction tracing;
-     *               <code>false</code> to disable this feature.
+     * @deprecated
+     * This method was intended to control instruction tracing.
+     * It has been superseded by JVM-specific tracing mechanisms.
+     * This method is subject to removal in a future version of Java SE.
+     *
+     * @param on ignored
      */
-    public native void traceInstructions(boolean on);
+    @Deprecated(since="9", forRemoval=true)
+    public void traceInstructions(boolean on) { }
 
     /**
-     * Enables/Disables tracing of method calls.
-     * If the <code>boolean</code> argument is <code>true</code>, this
-     * method suggests that the Java virtual machine emit debugging
-     * information for each method in the virtual machine as it is
-     * called. The format of this information, and the file or other output
-     * stream to which it is emitted, depends on the host environment. The
-     * virtual machine may ignore this request if it does not support
-     * this feature.
-     * <p>
-     * Calling this method with argument false suggests that the
-     * virtual machine cease emitting per-call debugging information.
+     * Not implemented, does nothing.
      *
-     * @param   on   <code>true</code> to enable instruction tracing;
-     *               <code>false</code> to disable this feature.
+     * @deprecated
+     * This method was intended to control method call tracing.
+     * It has been superseded by JVM-specific tracing mechanisms.
+     * This method is subject to removal in a future version of Java SE.
+     *
+     * @param on ignored
      */
-    public native void traceMethodCalls(boolean on);
+    @Deprecated(since="9", forRemoval=true)
+    public void traceMethodCalls(boolean on) { }
 
     /**
      * Loads the native library specified by the filename argument.  The filename
      * argument must be an absolute path name.
      * (for example
-     * <code>Runtime.getRuntime().load("/home/avh/lib/libX11.so");</code>).
+     * {@code Runtime.getRuntime().load("/home/avh/lib/libX11.so");}).
      *
      * If the filename argument, when stripped of any platform-specific library
      * prefix, path, and file extension, indicates a library whose name is,
      * for example, L, and a native library called L is statically linked
      * with the VM, then the JNI_OnLoad_L function exported by the library
      * is invoked rather than attempting to load a dynamic library.
      * A filename matching the argument does not have to exist in the file
-     * system. See the JNI Specification for more details.
+     * system.
+     * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
+     * for more details.
      *
      * Otherwise, the filename argument is mapped to a native library image in
      * an implementation-dependent manner.
      * <p>
-     * First, if there is a security manager, its <code>checkLink</code>
-     * method is called with the <code>filename</code> as its argument.
+     * First, if there is a security manager, its {@code checkLink}
+     * method is called with the {@code filename} as its argument.
      * This may result in a security exception.
      * <p>
      * This is similar to the method {@link #loadLibrary(String)}, but it
      * accepts a general file name as an argument rather than just a library
      * name, allowing any file of native code to be loaded.
      * <p>
      * The method {@link System#load(String)} is the conventional and
      * convenient means of invoking this method.
      *
      * @param      filename   the file to load.
-     * @exception  SecurityException  if a security manager exists and its
-     *             <code>checkLink</code> method doesn't allow
+     * @throws     SecurityException  if a security manager exists and its
+     *             {@code checkLink} method doesn't allow
      *             loading of the specified dynamic library
-     * @exception  UnsatisfiedLinkError  if either the filename is not an
+     * @throws     UnsatisfiedLinkError  if either the filename is not an
      *             absolute path name, the native library is not statically
      *             linked with the VM, or the library cannot be mapped to
      *             a native library image by the host system.
-     * @exception  NullPointerException if <code>filename</code> is
-     *             <code>null</code>
+     * @throws     NullPointerException if {@code filename} is
+     *             {@code null}
      * @see        java.lang.Runtime#getRuntime()
      * @see        java.lang.SecurityException
      * @see        java.lang.SecurityManager#checkLink(java.lang.String)
      */
     @CallerSensitive
     public void load(String filename) {
         load0(Reflection.getCallerClass(), filename);
     }
 
     synchronized void load0(Class<?> fromClass, String filename) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkLink(filename);
         }
         if (!(new File(filename).isAbsolute())) {
             throw new UnsatisfiedLinkError(
                 "Expecting an absolute path of the library: " + filename);
         }
         ClassLoader.loadLibrary(fromClass, filename, true);
     }
 
     /**
-     * Loads the native library specified by the <code>libname</code>
-     * argument.  The <code>libname</code> argument must not contain any platform
+     * Loads the native library specified by the {@code libname}
+     * argument.  The {@code libname} argument must not contain any platform
      * specific prefix, file extension or path. If a native library
-     * called <code>libname</code> is statically linked with the VM, then the
-     * JNI_OnLoad_<code>libname</code> function exported by the library is invoked.
-     * See the JNI Specification for more details.
+     * called {@code libname} is statically linked with the VM, then the
+     * JNI_OnLoad_{@code libname} function exported by the library is invoked.
+     * See the <a href="{@docRoot}/../specs/jni/index.html"> JNI Specification</a>
+     * for more details.
      *
      * Otherwise, the libname argument is loaded from a system library
      * location and mapped to a native library image in an implementation-
      * dependent manner.
      * <p>
-     * First, if there is a security manager, its <code>checkLink</code>
-     * method is called with the <code>libname</code> as its argument.
+     * First, if there is a security manager, its {@code checkLink}
+     * method is called with the {@code libname} as its argument.
      * This may result in a security exception.
      * <p>
      * The method {@link System#loadLibrary(String)} is the conventional
      * and convenient means of invoking this method. If native
      * methods are to be used in the implementation of a class, a standard
      * strategy is to put the native code in a library file (call it
-     * <code>LibFile</code>) and then to put a static initializer:
+     * {@code LibFile}) and then to put a static initializer:
      * <blockquote><pre>
      * static { System.loadLibrary("LibFile"); }
      * </pre></blockquote>
      * within the class declaration. When the class is loaded and
      * initialized, the necessary native code implementation for the native
      * methods will then be loaded as well.
      * <p>
      * If this method is called more than once with the same library
      * name, the second and subsequent calls are ignored.
      *
      * @param      libname   the name of the library.
-     * @exception  SecurityException  if a security manager exists and its
-     *             <code>checkLink</code> method doesn't allow
+     * @throws     SecurityException  if a security manager exists and its
+     *             {@code checkLink} method doesn't allow
      *             loading of the specified dynamic library
-     * @exception  UnsatisfiedLinkError if either the libname argument
+     * @throws     UnsatisfiedLinkError if either the libname argument
      *             contains a file path, the native library is not statically
      *             linked with the VM,  or the library cannot be mapped to a
      *             native library image by the host system.
-     * @exception  NullPointerException if <code>libname</code> is
-     *             <code>null</code>
+     * @throws     NullPointerException if {@code libname} is
+     *             {@code null}
      * @see        java.lang.SecurityException
      * @see        java.lang.SecurityManager#checkLink(java.lang.String)
      */
     @CallerSensitive
     public void loadLibrary(String libname) {
         loadLibrary0(Reflection.getCallerClass(), libname);
     }
 
     synchronized void loadLibrary0(Class<?> fromClass, String libname) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             security.checkLink(libname);
         }
         if (libname.indexOf((int)File.separatorChar) != -1) {
             throw new UnsatisfiedLinkError(
     "Directory separator should not appear in library name: " + libname);
         }
         ClassLoader.loadLibrary(fromClass, libname, false);
     }
 
     /**
-     * Creates a localized version of an input stream. This method takes
-     * an <code>InputStream</code> and returns an <code>InputStream</code>
-     * equivalent to the argument in all respects except that it is
-     * localized: as characters in the local character set are read from
-     * the stream, they are automatically converted from the local
-     * character set to Unicode.
-     * <p>
-     * If the argument is already a localized stream, it may be returned
-     * as the result.
+     * Returns the version of the Java Runtime Environment as a {@link Version}.
      *
-     * @param      in InputStream to localize
-     * @return     a localized input stream
-     * @see        java.io.InputStream
-     * @see        java.io.BufferedReader#BufferedReader(java.io.Reader)
-     * @see        java.io.InputStreamReader#InputStreamReader(java.io.InputStream)
-     * @deprecated As of JDK&nbsp;1.1, the preferred way to translate a byte
-     * stream in the local encoding into a character stream in Unicode is via
-     * the <code>InputStreamReader</code> and <code>BufferedReader</code>
-     * classes.
+     * @return  the {@link Version} of the Java Runtime Environment
+     *
+     * @since  9
      */
-    @Deprecated
-    public InputStream getLocalizedInputStream(InputStream in) {
-        return in;
+    public static Version version() {
+        if (version == null) {
+            version = new Version(VersionProps.versionNumbers(),
+                    VersionProps.pre(), VersionProps.build(),
+                    VersionProps.optional());
+        }
+        return version;
     }
 
     /**
-     * Creates a localized version of an output stream. This method
-     * takes an <code>OutputStream</code> and returns an
-     * <code>OutputStream</code> equivalent to the argument in all respects
-     * except that it is localized: as Unicode characters are written to
-     * the stream, they are automatically converted to the local
-     * character set.
-     * <p>
-     * If the argument is already a localized stream, it may be returned
-     * as the result.
+     * A representation of a version string for an implementation of the
+     * Java&nbsp;SE Platform.  A version string consists of a version number
+     * optionally followed by pre-release and build information.
      *
-     * @deprecated As of JDK&nbsp;1.1, the preferred way to translate a
-     * Unicode character stream into a byte stream in the local encoding is via
-     * the <code>OutputStreamWriter</code>, <code>BufferedWriter</code>, and
-     * <code>PrintWriter</code> classes.
+     * <h2><a id="verNum">Version numbers</a></h2>
      *
-     * @param      out OutputStream to localize
-     * @return     a localized output stream
-     * @see        java.io.OutputStream
-     * @see        java.io.BufferedWriter#BufferedWriter(java.io.Writer)
-     * @see        java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
-     * @see        java.io.PrintWriter#PrintWriter(java.io.OutputStream)
+     * <p> A <em>version number</em>, {@code $VNUM}, is a non-empty sequence of
+     * elements separated by period characters (U+002E).  An element is either
+     * zero, or an unsigned integer numeral without leading zeros.  The final
+     * element in a version number must not be zero.  When an element is
+     * incremented, all subsequent elements are removed.  The format is: </p>
+     *
+     * <blockquote><pre>
+     * [1-9][0-9]*((\.0)*\.[1-9][0-9]*)*
+     * </pre></blockquote>
+     *
+     * <p> The sequence may be of arbitrary length but the first four elements
+     * are assigned specific meanings, as follows:</p>
+     *
+     * <blockquote><pre>
+     * $FEATURE.$INTERIM.$UPDATE.$PATCH
+     * </pre></blockquote>
+     *
+     * <ul>
+     *
+     * <li><p> <a id="FEATURE">{@code $FEATURE}</a> &#x2014; The
+     * feature-release counter, incremented for every feature release
+     * regardless of release content.  Features may be added in a feature
+     * release; they may also be removed, if advance notice was given at least
+     * one feature release ahead of time.  Incompatible changes may be made
+     * when justified. </p></li>
+     *
+     * <li><p> <a id="INTERIM">{@code $INTERIM}</a> &#x2014; The
+     * interim-release counter, incremented for non-feature releases that
+     * contain compatible bug fixes and enhancements but no incompatible
+     * changes, no feature removals, and no changes to standard APIs.
+     * </p></li>
+     *
+     * <li><p> <a id="UPDATE">{@code $UPDATE}</a> &#x2014; The update-release
+     * counter, incremented for compatible update releases that fix security
+     * issues, regressions, and bugs in newer features. </p></li>
+     *
+     * <li><p> <a id="PATCH">{@code $PATCH}</a> &#x2014; The emergency
+     * patch-release counter, incremented only when it's necessary to produce
+     * an emergency release to fix a critical issue. </p></li>
+     *
+     * </ul>
+     *
+     * <p> The fifth and later elements of a version number are free for use by
+     * platform implementors, to identify implementor-specific patch
+     * releases. </p>
+     *
+     * <p> A version number never has trailing zero elements.  If an element
+     * and all those that follow it logically have the value zero then all of
+     * them are omitted. </p>
+     *
+     * <p> The sequence of numerals in a version number is compared to another
+     * such sequence in numerical, pointwise fashion; <em>e.g.</em>, {@code
+     * 10.0.4} is less than {@code 10.1.2}.  If one sequence is shorter than
+     * another then the missing elements of the shorter sequence are considered
+     * to be less than the corresponding elements of the longer sequence;
+     * <em>e.g.</em>, {@code 10.0.2} is less than {@code 10.0.2.1}. </p>
+     *
+     * <h2><a id="verStr">Version strings</a></h2>
+     *
+     * <p> A <em>version string</em>, {@code $VSTR}, is a version number {@code
+     * $VNUM}, as described above, optionally followed by pre-release and build
+     * information, in one of the following formats: </p>
+     *
+     * <blockquote><pre>
+     *     $VNUM(-$PRE)?\+$BUILD(-$OPT)?
+     *     $VNUM-$PRE(-$OPT)?
+     *     $VNUM(+-$OPT)?
+     * </pre></blockquote>
+     *
+     * <p> where: </p>
+     *
+     * <ul>
+     *
+     * <li><p> <a id="pre">{@code $PRE}</a>, matching {@code ([a-zA-Z0-9]+)}
+     * &#x2014; A pre-release identifier.  Typically {@code ea}, for a
+     * potentially unstable early-access release under active development, or
+     * {@code internal}, for an internal developer build. </p></li>
+     *
+     * <li><p> <a id="build">{@code $BUILD}</a>, matching {@code
+     * (0|[1-9][0-9]*)} &#x2014; The build number, incremented for each promoted
+     * build.  {@code $BUILD} is reset to {@code 1} when any portion of {@code
+     * $VNUM} is incremented. </p></li>
+     *
+     * <li><p> <a id="opt">{@code $OPT}</a>, matching {@code ([-a-zA-Z0-9.]+)}
+     * &#x2014; Additional build information, if desired.  In the case of an
+     * {@code internal} build this will often contain the date and time of the
+     * build. </p></li>
+     *
+     * </ul>
+     *
+     * <p> A version string {@code 10-ea} matches {@code $VNUM = "10"} and
+     * {@code $PRE = "ea"}.  The version string {@code 10+-ea} matches
+     * {@code $VNUM = "10"} and {@code $OPT = "ea"}. </p>
+     *
+     * <p> When comparing two version strings, the value of {@code $OPT}, if
+     * present, may or may not be significant depending on the chosen
+     * comparison method.  The comparison methods {@link #compareTo(Version)
+     * compareTo()} and {@link #compareToIgnoreOptional(Version)
+     * compareToIgnoreOptional()} should be used consistently with the
+     * corresponding methods {@link #equals(Object) equals()} and {@link
+     * #equalsIgnoreOptional(Object) equalsIgnoreOptional()}.  </p>
+     *
+     * <p> A <em>short version string</em>, {@code $SVSTR}, often useful in
+     * less formal contexts, is a version number optionally followed by a
+     * pre-release identifier:</p>
+     *
+     * <blockquote><pre>
+     *     $VNUM(-$PRE)?
+     * </pre></blockquote>
+     *
+     * <p>This is a <a href="./doc-files/ValueBased.html">value-based</a>
+     * class; use of identity-sensitive operations (including reference equality
+     * ({@code ==}), identity hash code, or synchronization) on instances of
+     * {@code Version} may have unpredictable results and should be avoided.
+     * </p>
+     *
+     * @since  9
      */
-    @Deprecated
-    public OutputStream getLocalizedOutputStream(OutputStream out) {
-        return out;
+    public static final class Version
+        implements Comparable<Version>
+    {
+        private final List<Integer>     version;
+        private final Optional<String>  pre;
+        private final Optional<Integer> build;
+        private final Optional<String>  optional;
+
+        /*
+         * List of version number components passed to this constructor MUST
+         * be at least unmodifiable (ideally immutable). In the case on an
+         * unmodifiable list, the caller MUST hand the list over to this
+         * constructor and never change the underlying list.
+         */
+        private Version(List<Integer> unmodifiableListOfVersions,
+                        Optional<String> pre,
+                        Optional<Integer> build,
+                        Optional<String> optional)
+        {
+            this.version = unmodifiableListOfVersions;
+            this.pre = pre;
+            this.build = build;
+            this.optional = optional;
+        }
+
+        /**
+         * Parses the given string as a valid
+         * <a href="#verStr">version string</a> containing a
+         * <a href="#verNum">version number</a> followed by pre-release and
+         * build information.
+         *
+         * @param  s
+         *         A string to interpret as a version
+         *
+         * @throws  IllegalArgumentException
+         *          If the given string cannot be interpreted as a valid
+         *          version
+         *
+         * @throws  NullPointerException
+         *          If the given string is {@code null}
+         *
+         * @throws  NumberFormatException
+         *          If an element of the version number or the build number
+         *          cannot be represented as an {@link Integer}
+         *
+         * @return  The Version of the given string
+         */
+        public static Version parse(String s) {
+            if (s == null)
+                throw new NullPointerException();
+
+            // Shortcut to avoid initializing VersionPattern when creating
+            // feature-version constants during startup
+            if (isSimpleNumber(s)) {
+                return new Version(List.of(Integer.parseInt(s)),
+                        Optional.empty(), Optional.empty(), Optional.empty());
+            }
+            Matcher m = VersionPattern.VSTR_PATTERN.matcher(s);
+            if (!m.matches())
+                throw new IllegalArgumentException("Invalid version string: '"
+                                                   + s + "'");
+
+            // $VNUM is a dot-separated list of integers of arbitrary length
+            String[] split = m.group(VersionPattern.VNUM_GROUP).split("\\.");
+            Integer[] version = new Integer[split.length];
+            for (int i = 0; i < split.length; i++) {
+                version[i] = Integer.parseInt(split[i]);
+            }
+
+            Optional<String> pre = Optional.ofNullable(
+                    m.group(VersionPattern.PRE_GROUP));
+
+            String b = m.group(VersionPattern.BUILD_GROUP);
+            // $BUILD is an integer
+            Optional<Integer> build = (b == null)
+                ? Optional.empty()
+                : Optional.of(Integer.parseInt(b));
+
+            Optional<String> optional = Optional.ofNullable(
+                    m.group(VersionPattern.OPT_GROUP));
+
+            // empty '+'
+            if (!build.isPresent()) {
+                if (m.group(VersionPattern.PLUS_GROUP) != null) {
+                    if (optional.isPresent()) {
+                        if (pre.isPresent())
+                            throw new IllegalArgumentException("'+' found with"
+                                + " pre-release and optional components:'" + s
+                                + "'");
+                    } else {
+                        throw new IllegalArgumentException("'+' found with neither"
+                            + " build or optional components: '" + s + "'");
+                    }
+                } else {
+                    if (optional.isPresent() && !pre.isPresent()) {
+                        throw new IllegalArgumentException("optional component"
+                            + " must be preceeded by a pre-release component"
+                            + " or '+': '" + s + "'");
+                    }
+                }
+            }
+            return new Version(List.of(version), pre, build, optional);
+        }
+
+        private static boolean isSimpleNumber(String s) {
+            for (int i = 0; i < s.length(); i++) {
+                char c = s.charAt(i);
+                char lowerBound = (i > 0) ? '0' : '1';
+                if (c < lowerBound || c > '9') {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        /**
+         * Returns the value of the <a href="#FEATURE">feature</a> element of
+         * the version number.
+         *
+         * @return The value of the feature element
+         *
+         * @since 10
+         */
+        public int feature() {
+            return version.get(0);
+        }
+
+        /**
+         * Returns the value of the <a href="#INTERIM">interim</a> element of
+         * the version number, or zero if it is absent.
+         *
+         * @return The value of the interim element, or zero
+         *
+         * @since 10
+         */
+        public int interim() {
+            return (version.size() > 1 ? version.get(1) : 0);
+        }
+
+        /**
+         * Returns the value of the <a href="#UPDATE">update</a> element of the
+         * version number, or zero if it is absent.
+         *
+         * @return The value of the update element, or zero
+         *
+         * @since 10
+         */
+        public int update() {
+            return (version.size() > 2 ? version.get(2) : 0);
+        }
+
+        /**
+         * Returns the value of the <a href="#PATCH">patch</a> element of the
+         * version number, or zero if it is absent.
+         *
+         * @return The value of the patch element, or zero
+         *
+         * @since 10
+         */
+        public int patch() {
+            return (version.size() > 3 ? version.get(3) : 0);
+        }
+
+        /**
+         * Returns the value of the major element of the version number.
+         *
+         * @deprecated As of Java&nbsp;SE 10, the first element of a version
+         * number is not the major-release number but the feature-release
+         * counter, incremented for every time-based release.  Use the {@link
+         * #feature()} method in preference to this method.  For compatibility,
+         * this method returns the value of the <a href="#FEATURE">feature</a>
+         * element.
+         *
+         * @return The value of the feature element
+         */
+        @Deprecated(since = "10")
+        public int major() {
+            return feature();
+        }
+
+        /**
+         * Returns the value of the minor element of the version number, or
+         * zero if it is absent.
+         *
+         * @deprecated As of Java&nbsp;SE 10, the second element of a version
+         * number is not the minor-release number but the interim-release
+         * counter, incremented for every interim release.  Use the {@link
+         * #interim()} method in preference to this method.  For compatibility,
+         * this method returns the value of the <a href="#INTERIM">interim</a>
+         * element, or zero if it is absent.
+         *
+         * @return The value of the interim element, or zero
+         */
+        @Deprecated(since = "10")
+        public int minor() {
+            return interim();
+        }
+
+        /**
+         * Returns the value of the security element of the version number, or
+         * zero if it is absent.
+         *
+         * @deprecated As of Java&nbsp;SE 10, the third element of a version
+         * number is not the security level but the update-release counter,
+         * incremented for every update release.  Use the {@link #update()}
+         * method in preference to this method.  For compatibility, this method
+         * returns the value of the <a href="#UPDATE">update</a> element, or
+         * zero if it is absent.
+         *
+         * @return  The value of the update element, or zero
+         */
+        @Deprecated(since = "10")
+        public int security() {
+            return update();
+        }
+
+        /**
+         * Returns an unmodifiable {@link java.util.List List} of the integers
+         * represented in the <a href="#verNum">version number</a>.
+         * The {@code List} always contains at least one element corresponding to
+         * the <a href="#FEATURE">feature version number</a>.
+         *
+         * @return  An unmodifiable list of the integers
+         *          represented in the version number
+         */
+        public List<Integer> version() {
+            return version;
+        }
+
+        /**
+         * Returns the optional <a href="#pre">pre-release</a> information.
+         *
+         * @return  The optional pre-release information as a String
+         */
+        public Optional<String> pre() {
+            return pre;
+        }
+
+        /**
+         * Returns the <a href="#build">build number</a>.
+         *
+         * @return  The optional build number.
+         */
+        public Optional<Integer> build() {
+            return build;
+        }
+
+        /**
+         * Returns <a href="#opt">optional</a> additional identifying build
+         * information.
+         *
+         * @return  Additional build information as a String
+         */
+        public Optional<String> optional() {
+            return optional;
+        }
+
+        /**
+         * Compares this version to another.
+         *
+         * <p> Each of the components in the <a href="#verStr">version</a> is
+         * compared in the following order of precedence: version numbers,
+         * pre-release identifiers, build numbers, optional build information.
+         * </p>
+         *
+         * <p> Comparison begins by examining the sequence of version numbers.
+         * If one sequence is shorter than another, then the missing elements
+         * of the shorter sequence are considered to be less than the
+         * corresponding elements of the longer sequence. </p>
+         *
+         * <p> A version with a pre-release identifier is always considered to
+         * be less than a version without one.  Pre-release identifiers are
+         * compared numerically when they consist only of digits, and
+         * lexicographically otherwise.  Numeric identifiers are considered to
+         * be less than non-numeric identifiers.  </p>
+         *
+         * <p> A version without a build number is always less than one with a
+         * build number; otherwise build numbers are compared numerically. </p>
+         *
+         * <p> The optional build information is compared lexicographically.
+         * During this comparison, a version with optional build information is
+         * considered to be greater than a version without one. </p>
+         *
+         * @param  obj
+         *         The object to be compared
+         *
+         * @return  A negative integer, zero, or a positive integer if this
+         *          {@code Version} is less than, equal to, or greater than the
+         *          given {@code Version}
+         *
+         * @throws  NullPointerException
+         *          If the given object is {@code null}
+         */
+        @Override
+        public int compareTo(Version obj) {
+            return compare(obj, false);
+        }
+
+        /**
+         * Compares this version to another disregarding optional build
+         * information.
+         *
+         * <p> Two versions are compared by examining the version string as
+         * described in {@link #compareTo(Version)} with the exception that the
+         * optional build information is always ignored. </p>
+         *
+         * <p> This method provides ordering which is consistent with
+         * {@code equalsIgnoreOptional()}. </p>
+         *
+         * @param  obj
+         *         The object to be compared
+         *
+         * @return  A negative integer, zero, or a positive integer if this
+         *          {@code Version} is less than, equal to, or greater than the
+         *          given {@code Version}
+         *
+         * @throws  NullPointerException
+         *          If the given object is {@code null}
+         */
+        public int compareToIgnoreOptional(Version obj) {
+            return compare(obj, true);
+        }
+
+        private int compare(Version obj, boolean ignoreOpt) {
+            if (obj == null)
+                throw new NullPointerException();
+
+            int ret = compareVersion(obj);
+            if (ret != 0)
+                return ret;
+
+            ret = comparePre(obj);
+            if (ret != 0)
+                return ret;
+
+            ret = compareBuild(obj);
+            if (ret != 0)
+                return ret;
+
+            if (!ignoreOpt)
+                return compareOptional(obj);
+
+            return 0;
+        }
+
+        private int compareVersion(Version obj) {
+            int size = version.size();
+            int oSize = obj.version().size();
+            int min = Math.min(size, oSize);
+            for (int i = 0; i < min; i++) {
+                int val = version.get(i);
+                int oVal = obj.version().get(i);
+                if (val != oVal)
+                    return val - oVal;
+            }
+            return size - oSize;
+        }
+
+        private int comparePre(Version obj) {
+            Optional<String> oPre = obj.pre();
+            if (!pre.isPresent()) {
+                if (oPre.isPresent())
+                    return 1;
+            } else {
+                if (!oPre.isPresent())
+                    return -1;
+                String val = pre.get();
+                String oVal = oPre.get();
+                if (val.matches("\\d+")) {
+                    return (oVal.matches("\\d+")
+                        ? (new BigInteger(val)).compareTo(new BigInteger(oVal))
+                        : -1);
+                } else {
+                    return (oVal.matches("\\d+")
+                        ? 1
+                        : val.compareTo(oVal));
+                }
+            }
+            return 0;
+        }
+
+        private int compareBuild(Version obj) {
+            Optional<Integer> oBuild = obj.build();
+            if (oBuild.isPresent()) {
+                return (build.isPresent()
+                        ? build.get().compareTo(oBuild.get())
+                        : -1);
+            } else if (build.isPresent()) {
+                return 1;
+            }
+            return 0;
+        }
+
+        private int compareOptional(Version obj) {
+            Optional<String> oOpt = obj.optional();
+            if (!optional.isPresent()) {
+                if (oOpt.isPresent())
+                    return -1;
+            } else {
+                if (!oOpt.isPresent())
+                    return 1;
+                return optional.get().compareTo(oOpt.get());
+            }
+            return 0;
+        }
+
+        /**
+         * Returns a string representation of this version.
+         *
+         * @return  The version string
+         */
+        @Override
+        public String toString() {
+            StringBuilder sb
+                = new StringBuilder(version.stream()
+                    .map(Object::toString)
+                    .collect(Collectors.joining(".")));
+
+            pre.ifPresent(v -> sb.append("-").append(v));
+
+            if (build.isPresent()) {
+                sb.append("+").append(build.get());
+                if (optional.isPresent())
+                    sb.append("-").append(optional.get());
+            } else {
+                if (optional.isPresent()) {
+                    sb.append(pre.isPresent() ? "-" : "+-");
+                    sb.append(optional.get());
+                }
+            }
+
+            return sb.toString();
+        }
+
+        /**
+         * Determines whether this {@code Version} is equal to another object.
+         *
+         * <p> Two {@code Version}s are equal if and only if they represent the
+         * same version string.
+         *
+         * @param  obj
+         *         The object to which this {@code Version} is to be compared
+         *
+         * @return  {@code true} if, and only if, the given object is a {@code
+         *          Version} that is identical to this {@code Version}
+         *
+         */
+        @Override
+        public boolean equals(Object obj) {
+            boolean ret = equalsIgnoreOptional(obj);
+            if (!ret)
+                return false;
+
+            Version that = (Version)obj;
+            return (this.optional().equals(that.optional()));
+        }
+
+        /**
+         * Determines whether this {@code Version} is equal to another
+         * disregarding optional build information.
+         *
+         * <p> Two {@code Version}s are equal if and only if they represent the
+         * same version string disregarding the optional build information.
+         *
+         * @param  obj
+         *         The object to which this {@code Version} is to be compared
+         *
+         * @return  {@code true} if, and only if, the given object is a {@code
+         *          Version} that is identical to this {@code Version}
+         *          ignoring the optional build information
+         *
+         */
+        public boolean equalsIgnoreOptional(Object obj) {
+            if (this == obj)
+                return true;
+            if (!(obj instanceof Version))
+                return false;
+
+            Version that = (Version)obj;
+            return (this.version().equals(that.version())
+                && this.pre().equals(that.pre())
+                && this.build().equals(that.build()));
+        }
+
+        /**
+         * Returns the hash code of this version.
+         *
+         * @return  The hashcode of this version
+         */
+        @Override
+        public int hashCode() {
+            int h = 1;
+            int p = 17;
+
+            h = p * h + version.hashCode();
+            h = p * h + pre.hashCode();
+            h = p * h + build.hashCode();
+            h = p * h + optional.hashCode();
+
+            return h;
+        }
     }
 
+    private static class VersionPattern {
+        // $VNUM(-$PRE)?(\+($BUILD)?(\-$OPT)?)?
+        // RE limits the format of version strings
+        // ([1-9][0-9]*(?:(?:\.0)*\.[1-9][0-9]*)*)(?:-([a-zA-Z0-9]+))?(?:(\+)(0|[1-9][0-9]*)?)?(?:-([-a-zA-Z0-9.]+))?
+
+        private static final String VNUM
+            = "(?<VNUM>[1-9][0-9]*(?:(?:\\.0)*\\.[1-9][0-9]*)*)";
+        private static final String PRE      = "(?:-(?<PRE>[a-zA-Z0-9]+))?";
+        private static final String BUILD
+            = "(?:(?<PLUS>\\+)(?<BUILD>0|[1-9][0-9]*)?)?";
+        private static final String OPT      = "(?:-(?<OPT>[-a-zA-Z0-9.]+))?";
+        private static final String VSTR_FORMAT = VNUM + PRE + BUILD + OPT;
+
+        static final Pattern VSTR_PATTERN = Pattern.compile(VSTR_FORMAT);
+
+        static final String VNUM_GROUP  = "VNUM";
+        static final String PRE_GROUP   = "PRE";
+        static final String PLUS_GROUP  = "PLUS";
+        static final String BUILD_GROUP = "BUILD";
+        static final String OPT_GROUP   = "OPT";
+    }
 }