Swing/AWT/SWT :: JTable Cell Renderer Causing Program To Go Black When Minimized

I'm making a program that selects classes from a database via a jcombo box and then populates a time table with the class times.

I've used a custom cellrenderer that extends DefaultTableCellRenderer to text wrap the information and change the background of the cells.

It works but when i minimize the program it goes all black and if I double click I get a new JTextArea opening up on the timetable and when I minimize the program and go to open it again i get an "Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException" and the cell render seems to be called again even though i haven't rerun the program.

This is the cell renderer that I built

public class TimesTableCellRenderer extends DefaultTableCellRenderer {
private int minHeight = -1;
private final JLabel label = new JLabel();
private final JTextArea textArea = new JTextArea();
public TimesTableCellRenderer(){
super();
textArea.setLineWrap(true);

[Code] ....