1 /*
   2  * Copyright (c) 1994, 2005, 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 
  26 package java.lang;
  27 
  28 /**
  29  * The <code>Runnable</code> interface should be implemented by any
  30  * class whose instances are intended to be executed by a thread. The
  31  * class must define a method of no arguments called <code>run</code>.
  32  * <p>
  33  * This interface is designed to provide a common protocol for objects that
  34  * wish to execute code while they are active. For example,
  35  * <code>Runnable</code> is implemented by class <code>Thread</code>.
  36  * Being active simply means that a thread has been started and has not
  37  * yet been stopped.
  38  * <p>
  39  * In addition, <code>Runnable</code> provides the means for a class to be
  40  * active while not subclassing <code>Thread</code>. A class that implements
  41  * <code>Runnable</code> can run without subclassing <code>Thread</code>
  42  * by instantiating a <code>Thread</code> instance and passing itself in
  43  * as the target.  In most cases, the <code>Runnable</code> interface should
  44  * be used if you are only planning to override the <code>run()</code>
  45  * method and no other <code>Thread</code> methods.
  46  * This is important because classes should not be subclassed
  47  * unless the programmer intends on modifying or enhancing the fundamental
  48  * behavior of the class.
  49  *
  50  * @author  Arthur van Hoff
  51  * @see     java.lang.Thread
  52  * @see     java.util.concurrent.Callable
  53  * @since   JDK1.0
  54  */
  55 public
  56 interface Runnable {
  57     /**
  58      * When an object implementing interface <code>Runnable</code> is used
  59      * to create a thread, starting the thread causes the object's
  60      * <code>run</code> method to be called in that separately executing
  61      * thread.
  62      * <p>
  63      * The general contract of the method <code>run</code> is that it may
  64      * take any action whatsoever.
  65      *
  66      * @see     java.lang.Thread#run()
  67      */
  68     public abstract void run();
  69 }