title: Class implements Runnable but start() and sleep() methods are not defined
body: <p>I've created a class called <code>Thread</code> that implements <code>Runnable</code> but I cannot invoke the <code>start()</code> or <code>sleep()</code> methods for some reason. Any time I attempt to do so, I get errors saying that these methods are undefined for the class and suggests that I create them. So I created a new project and copied a sample code to see if there was something wrong with my own code and I received the same errors. Here's the sample code:</p>
  
  <pre><code>class Thread implements Runnable {
      private int a;
      public Thread (int a) {
          this.a = a;
      }
      public void run() {
          for (int i = 1; i &lt;= a; ++i) {
              System.out.println(Thread.currentThread().getName() + " is " + i);
              try {
                  Thread.sleep(1000);
              } catch (InterruptedException e) {}
          }
      }
  }
  </code></pre>
  
  <p>and this is my own code:</p>
  
  <pre><code>public class Thread extends PID implements Runnable {
      public Thread() {};                      // Empty constructor for thread object
      public void run() {
          Random gen = new Random();           // Generates random values
          int sleepTime;                       // Sleep time
          sleepTime = gen.nextInt(60 - 1) + 1; // Generates random sleep time between 1 and 60 seconds
          try {
              Thread.sleep();
          } catch (Exception e) {
              System.out.println(e);
          } 
          System.out.println("The thread has been terminated");
      }
  }
  </code></pre>