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POWhat is going on here? Illegal Argument Exception w/ Violates Contract Error
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  1. POWhat is going on here? Illegal Argument Exception w/ Violates Contract Error
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    copied!<p>I was trying to help a friend debug but I can't seem to figure out the issue.</p> <p>The specs of the code are very explicit:</p> <ol> <li>Use buttons to draw a race track</li> <li>Use threads to move buttons as JRacers</li> <li>Implement JSpinners to carry information on # of laps and # of racers</li> </ol> <p>For some reason his program appears to work fine yet Java still throws an error at him involving violating a contract...</p> <p>Here is the error:</p> <pre><code>&gt; Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: Comparison method violates its general contract! at java.util.TimSort.mergeHi(TimSort.java:868) at java.util.TimSort.mergeAt(TimSort.java:485) at java.util.TimSort.mergeForceCollapse(TimSort.java:426) at java.util.TimSort.sort(TimSort.java:223) at java.util.TimSort.sort(TimSort.java:173) at java.util.Arrays.sort(Arrays.java:659) at java.util.Collections.sort(Collections.java:217) at javax.swing.SortingFocusTraversalPolicy.enumerateAndSortCycle(SortingFocusTraversalPolicy.java:136) at javax.swing.SortingFocusTraversalPolicy.getFocusTraversalCycle(SortingFocusTraversalPolicy.java:110) at javax.swing.SortingFocusTraversalPolicy.getComponentAfter(SortingFocusTraversalPolicy.java:280) at javax.swing.LayoutFocusTraversalPolicy.getComponentAfter(LayoutFocusTraversalPolicy.java:106) at javax.swing.plaf.basic.BasicSpinnerUI$ArrowButtonHandler.focusSpinnerIfNecessary(BasicSpinnerUI.java:812) at javax.swing.plaf.basic.BasicSpinnerUI$ArrowButtonHandler.mousePressed(BasicSpinnerUI.java:770) at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:280) at java.awt.Component.processMouseEvent(Component.java:6502) at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) at java.awt.Component.processEvent(Component.java:6270) at java.awt.Container.processEvent(Container.java:2229) at java.awt.Component.dispatchEventImpl(Component.java:4861) at java.awt.Container.dispatchEventImpl(Container.java:2287) at java.awt.Component.dispatchEvent(Component.java:4687) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4489) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422) at java.awt.Container.dispatchEventImpl(Container.java:2273) at java.awt.Window.dispatchEventImpl(Window.java:2719) at java.awt.Component.dispatchEvent(Component.java:4687) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:723) at java.awt.EventQueue.access$200(EventQueue.java:103) at java.awt.EventQueue$3.run(EventQueue.java:682) at java.awt.EventQueue$3.run(EventQueue.java:680) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87) at java.awt.EventQueue$4.run(EventQueue.java:696) at java.awt.EventQueue$4.run(EventQueue.java:694) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:693) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139) at java.awt.EventDispatchThread.run(EventDispatchThread.java:97) </code></pre> <p>Here is the code:</p> <pre><code>import java.awt.Color; import java.awt.Dimension; import java.awt.Font; import java.awt.Graphics; import java.awt.event.*; import java.util.logging.Level; import java.util.logging.Logger; import javax.swing.*; import javax.swing.JPanel; import javax.swing.event.ChangeEvent; import javax.swing.event.ChangeListener; class CntlPanel extends JPanel implements ChangeListener { static JSpinner tempjs; static JSpinner js = new JSpinner(); static JLabel jl = new JLabel(); static JSpinner js2 = new JSpinner(); static JLabel jl2 = new JLabel(); static JButton start = new JButton(); static JButton set = new JButton(); public CntlPanel() { setSize(150,125); setBackground(Color.LIGHT_GRAY); setLocation(425,230); } public void buttonset(int next) { if (next == 0) { js2.setPreferredSize(new Dimension(45,25)); jl2.setPreferredSize(new Dimension(50,25)); js.setPreferredSize(new Dimension(45,25)); jl.setPreferredSize(new Dimension(50,25)); set.setPreferredSize(new Dimension(100,35)); jl.setText("Racers"); set.setText("Set Racers"); js.setValue(1); jl2.setText("Laps"); js2.setValue(1); js.addChangeListener(this); js2.addChangeListener(this); add(js); add(jl); add(js2); add(jl2); add(set); } if (next == 1) { JLabel jl1 = new JLabel(); jl1.setPreferredSize(new Dimension(50,25)); System.out.print("Bye"); start.setPreferredSize(new Dimension(100,35)); start.setText("START"); add(jl1); add(start); } } @Override public void stateChanged(ChangeEvent e) { if (e.getSource()== js) { if ((int)js.getValue() &lt; 1) { js.setValue(1); } if ((int)js.getValue() &gt; 4) { js.setValue(4); } } if (e.getSource() == js2) { if ((int)js2.getValue() &lt; 1) { js2.setValue(1); } } } } </code></pre> <p>What I have been able to determine:</p> <ol> <li>The contract error involves non-transitivity of a compare method</li> <li>He never edits or messes around with the compare method... I questioned whether the use == to compare certain objects was a problem but after switching to the .equals() notation the error persisted</li> </ol> <p>I am quite lost as to how to debug this.</p>
 

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