JMenuItem.setEnabled(boolean b) has the following syntax.
public void setEnabled(boolean b)
In the following code shows how to use JMenuItem.setEnabled(boolean b) method.
//from w ww . j a va2 s. co m import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import javax.swing.AbstractButton; import javax.swing.Icon; import javax.swing.JCheckBoxMenuItem; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; public class Main { public static void main(final String args[]) { JFrame frame = new JFrame("MenuSample Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JMenuBar menuBar = new JMenuBar(); // File Menu, F - Mnemonic JMenu fileMenu = new JMenu("File"); menuBar.add(fileMenu); // File->New, N - Mnemonic JMenuItem newMenuItem = new JMenuItem("New", KeyEvent.VK_N); newMenuItem.setEnabled(false); fileMenu.add(newMenuItem); JCheckBoxMenuItem caseMenuItem = new JCheckBoxMenuItem("Case Sensitive"); caseMenuItem.setMnemonic(KeyEvent.VK_C); fileMenu.add(caseMenuItem); ActionListener aListener = new ActionListener() { public void actionPerformed(ActionEvent event) { AbstractButton aButton = (AbstractButton) event.getSource(); boolean selected = aButton.getModel().isSelected(); String newLabel; if (selected) { newLabel = "A"; } else { newLabel = "B"; } aButton.setText(newLabel); } }; caseMenuItem.addActionListener(aListener); frame.setJMenuBar(menuBar); frame.setSize(350, 250); frame.setVisible(true); } }