code: /*
   * Copyright (c) 1994, 2013, 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;
  
  /**
   * The <code>Runnable</code> interface should be implemented by any
   * class whose instances are intended to be executed by a thread. The
   * class must define a method of no arguments called <code>run</code>.
   * <p>
   * This interface is designed to provide a common protocol for objects that
   * wish to execute code while they are active. For example,
   * <code>Runnable</code> is implemented by class <code>Thread</code>.
   * Being active simply means that a thread has been started and has not
   * yet been stopped.
   * <p>
   * In addition, <code>Runnable</code> provides the means for a class to be
   * active while not subclassing <code>Thread</code>. A class that implements
   * <code>Runnable</code> can run without subclassing <code>Thread</code>
   * by instantiating a <code>Thread</code> instance and passing itself in
   * as the target.  In most cases, the <code>Runnable</code> interface should
   * be used if you are only planning to override the <code>run()</code>
   * method and no other <code>Thread</code> methods.
   * This is important because classes should not be subclassed
   * unless the programmer intends on modifying or enhancing the fundamental
   * behavior of the class.
   *
   * @author  Arthur van Hoff
   * @see     java.lang.Thread
   * @see     java.util.concurrent.Callable
   * @since   JDK1.0
   */
  @FunctionalInterface
  public interface Runnable {
      /**
       * When an object implementing interface <code>Runnable</code> is used
       * to create a thread, starting the thread causes the object's
       * <code>run</code> method to be called in that separately executing
       * thread.
       * <p>
       * The general contract of the method <code>run</code> is that it may
       * take any action whatsoever.
       *
       * @see     java.lang.Thread#run()
       */
      public abstract void run();
  }
  