pickP.setLayout(new GridLayout(height, width));
pickF.setContentPane(pickP);

pickF.pack();
pickF.setVisible(true);             //when i remove this line, the error goes away.
pickF.setResizable(false);
pickF.setLocationRelativeTo(null);

package chap9ex14new;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class Chap9ex14new implements ActionListener{
    JFrame pickF, runF, menuF;
    JPanel pickP, runP, menuP;
    JButton start, stop;
    JCheckBox[][] init;
    JLabel[][] cell;
    boolean[][] cellB;
   
    ImageIcon ON;
    ImageIcon OFF;
   
    String path;
    int height, width;
   
    public Chap9ex14new(){
        path = Chap9ex14new.class.getProtectionDomain().getCodeSource().getLocation().getPath();
        OFF = new ImageIcon(path+"/OFF.jpg");
        ON = new ImageIcon(path+"/ON.png");
   
        height = 70;
        width = 115;
       
        pickF = new JFrame("The Game of Life");
                pickF.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        runF = new JFrame("The Game of Life");
                runF.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       
        pickP = new JPanel();
        pickP.setSize(width, height);
        runP = new JPanel();
        runP.setSize(width, height);
       
         start = new JButton("Start");
         start.setActionCommand("start");
         start.addActionListener(this);
         
         stop = new JButton("Stop");
         stop.setActionCommand("stop");
         stop.addActionListener(this);
         
         cell = new JLabel[height][width];      //Label Cells
            for (int i = 0; i <height; i++){       
                 for (int s = 0; s < width; s++){
                  cell[i][s] = new JLabel("hi");
                  runP.add(cell[i][s]);
                 }
             }
           
         cellB = new boolean[height][width];
            for (int i = 0; i <height; i++){        //Boolean Cells
                 for (int s = 0; s < width; s++){
                  cellB[i][s] = false;
                }
            }
           
         init = new JCheckBox[height][width];
            for (int i = 0; i < height ;i++){         //CheckBoxes
                 for (int s = 0; s < width; s++){
                 init[i][s] = new JCheckBox(OFF);
                 init[i][s].setSelectedIcon(ON);
                 
                 String a = Integer.toString(i);
                 String b = Integer.toString(s);
                 init[i][s].setActionCommand("b"+a+b);
                 
                 pickP.add(init[i][s]);
                 
                 System.out.println(init[i][s].getPreferredSize());
            }
        }
           
        runP.setLayout(new GridLayout(height, width));
        runF.setContentPane(runP);
       
        runF.pack();
        runF.setVisible(true);
        runF.setResizable(false);
        runF.setLocationRelativeTo(null);
       
        pickP.setLayout(new GridLayout(height, width));
        pickF.setContentPane(pickP);
   
        pickF.pack();
        pickF.setVisible(true);                                //this line causes the error. when I remove "pickF.setVisible(true);"
        pickF.setResizable(false);                                                                     //the the error goes away   
        pickF.setLocationRelativeTo(null);
       
           
    }
   
    @Override
    public void actionPerformed(ActionEvent event){
       
    }
   
    private static void runGUI(){
         Chap9ex14new run = new Chap9ex14new();
    }
    public static void main(String[] args) {
       javax.swing.SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run(){
                runGUI();
            }
        });
    }
}

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: Comparison method violates its general contract!
        at java.util.TimSort.mergeLo(Unknown Source)
        at java.util.TimSort.mergeAt(Unknown Source)
        at java.util.TimSort.mergeCollapse(Unknown Source)
        at java.util.TimSort.sort(Unknown Source)
        at java.util.TimSort.sort(Unknown Source)
        at java.util.Arrays.sort(Unknown Source)
        at java.util.Collections.sort(Unknown Source)
        at javax.swing.SortingFocusTraversalPolicy.enumerateAndSortCycle(Unknown Source)
        at javax.swing.SortingFocusTraversalPolicy.getFocusTraversalCycle(Unknown Source)
        at javax.swing.SortingFocusTraversalPolicy.getFirstComponent(Unknown Source)
        at javax.swing.LayoutFocusTraversalPolicy.getFirstComponent(Unknown Source)
        at javax.swing.SortingFocusTraversalPolicy.getDefaultComponent(Unknown Source)
        at java.awt.FocusTraversalPolicy.getInitialComponent(Unknown Source)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
        at java.awt.Component.dispatchEventImpl(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.SequencedEvent.dispatch(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)