title: cannot be cast to java.lang.Comparable - I get this error when not using Comparable
body: <p>Here is the code that the program breaks on (second line, <code>Arrays.sort</code>):</p>
  
  <pre><code>public void check3Kind(){       
      Arrays.sort(YahtzeeGUI.getGame().getDice()); //sorts the array so i can check for identical numbers in order
  
      int dice0 = YahtzeeGUI.getGame().getDice(0).getFaceValue();
      int dice1 = YahtzeeGUI.getGame().getDice(1).getFaceValue();
      int dice2 = YahtzeeGUI.getGame().getDice(2).getFaceValue();
      int dice3 = YahtzeeGUI.getGame().getDice(3).getFaceValue();
      int dice4 = YahtzeeGUI.getGame().getDice(4).getFaceValue();
  
      int score = + dice0 + dice1 + dice2 + dice3 + dice4;
  
      if ( (dice0 == dice1 &amp;&amp; dice0 == dice2) || (dice1 == dice2 &amp;&amp; dice1 == dice3) || (dice2 == dice3 &amp;&amp; dice2 == dice4)){
          YahtzeeGUI.setBtnScore(11, score);
      }
  }
  </code></pre>
  
  <p>It spits out this error:</p>
  
  <pre><code>Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: Dice cannot be cast to java.lang.Comparable
  at java.util.ComparableTimSort.countRunAndMakeAscending(Unknown Source)
  at java.util.ComparableTimSort.sort(Unknown Source)
  at java.util.ComparableTimSort.sort(Unknown Source)
  at java.util.Arrays.sort(Unknown Source)
  at Scoring.check3Kind(Scoring.java:84)
  at YahtzeeGUI$RollHandler.actionPerformed(YahtzeeGUI.java:235)
  at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
  at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
  at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
  at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
  at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
  at java.awt.Component.processMouseEvent(Unknown Source)
  at javax.swing.JComponent.processMouseEvent(Unknown Source)
  at java.awt.Component.processEvent(Unknown Source)
  at java.awt.Container.processEvent(Unknown Source)
  at java.awt.Component.dispatchEventImpl(Unknown Source)
  at java.awt.Container.dispatchEventImpl(Unknown Source)
  at java.awt.Component.dispatchEvent(Unknown Source)
  at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
  at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
  at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
  at java.awt.Container.dispatchEventImpl(Unknown Source)
  at java.awt.Window.dispatchEventImpl(Unknown Source)
  at java.awt.Component.dispatchEvent(Unknown Source)
  at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
  at java.awt.EventQueue.access$200(Unknown Source)
  at java.awt.EventQueue$3.run(Unknown Source)
  at java.awt.EventQueue$3.run(Unknown Source)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
  at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
  at java.awt.EventQueue$4.run(Unknown Source)
  at java.awt.EventQueue$4.run(Unknown Source)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
  at java.awt.EventQueue.dispatchEvent(Unknown Source)
  at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
  at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
  at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
  at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
  at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
  at java.awt.EventDispatchThread.run(Unknown Source)
  </code></pre>
  
  <p>I think it's something to do with sorting the array, but I'm not too sure. I've never used Comparable and don't really understand how to use it in this context</p>
  
  <p>Get Game:</p>
  
  <pre><code>private static Yahtzee y = new Yahtzee();
  
  public static Yahtzee getGame(){
      return y;
  }
  </code></pre>
  
  <p>Get Dice:</p>
  
  <pre><code>private Dice[] dice = new Dice[5];
  
  public Dice[] getDice(){
      return dice;
  }
  </code></pre>