"AWT-EventQueue-0" java.lang.NullPointerException
I am changing an existing program that used to work fine in JRE1.3. When I upgraded to JRE 1.6, the dialog box hang and does not display ComboBox.
Below is the code and the stack trace.
import irsccmacros.back_end.common.ComboBoxItem;
public class DefaultComboBoxRenderer
extends javax.swing.JLabel
implements javax.swing.ListCellRenderer {
/**
* ProcessingKindComboBoxRenderer constructor comment.
*/
public DefaultComboBoxRenderer() {
setOpaque(true);
setHorizontalAlignment(LEFT);
setVerticalAlignment(CENTER);
}
/**
* Return a component that has been configured to display the specified
* value. That component's <code>paint</code> method is then called to
* "render" the cell. If it is necessary to compute the dimensions
* of a list because the list cells do not have a fixed size, this method
* is called to generate a component on which <code>getPreferredSize</code>
* can be invoked.
*
* @param list The JList we're painting.
* @param value The value returned by list.getModel().getElementAt(index).
* @param index The cells index.
* @param isSelected True if the specified cell was selected.
* @param cellHasFocus True if the specified cell has the focus.
* @return A component whose paint() method will render the specified value.
*
* @see JList
* @see ListSelectionModel
* @see ListModel
*/
public java.awt.Component getListCellRendererComponent(
javax.swing.JList list,
Object value,
int index,
boolean isSelected,
boolean cellHasFocus) {
if (isSelected) {
setBackground(list.getSelectionBackground());
setForeground(list.getSelectionForeground());
} else {
setBackground(list.getBackground());
setForeground(list.getForeground());
}
if (value instanceof ComboBoxItem) {
if (((ComboBoxItem) value).getValue() >= 0) setText(((ComboBoxItem) value).getName());
} else setText(value.toString());
return this;
}
}
//////////////////////////////////////////////////////////////////////////////////////
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
[15:12:47,901,System.out]
at irsccmacros.front_end.common.presentation.DefaultComboBoxRenderer.getListCellRendererComponent(DefaultComboBoxRenderer.java)
[15:12:47,901,System.out]
at javax.swing.plaf.basic.BasicComboBoxUI.paintCurrentValue(Unknown Source)
[15:12:47,901,System.out]
at com.sun.java.swing.plaf.windows.WindowsComboBoxUI.paintCurrentValue(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.plaf.basic.BasicComboBoxUI.paint(Unknown Source)
[15:12:47,901,System.out]
at com.sun.java.swing.plaf.windows.WindowsComboBoxUI.paint(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.plaf.ComponentUI.update(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paintComponent(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paint(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paintChildren(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paint(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paintChildren(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paint(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paintChildren(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paint(Unknown Source)
[15:12:47,901,System.out]
at javax.swing.JComponent.paintChildren(Unknown Source)
