setType(), sets the type of the window.

The method setType(Window.Type type) sets the type of the window. This method can only be called while the window is not displayable.

Where type can be:

• Type.NORMAL: Represents a normal window. This is the default type for objects of the Window class or its descendants. Use this type for regular top-level windows.
• Type.POPUP: Represents a popup window. A popup window is a temporary window such as a drop-down menu or a tooltip. On some platforms, windows of that type may be forcibly made undecorated even if they are instances of the Frame or Dialog class, and have decorations enabled.
• Type.UTILITY: Represents a utility window. A utility window is usually a small window such as a toolbar or a palette. The native system may render the window with smaller title-bar if the window is either a Frame or a Dialog object, and if it has its decorations enabled.

Example:

- Create a new Java project of Java application, with main code named JavaTestSwing.java and JFrameWin.java extends javax.swing.JFrame.

package javatestswing;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Box;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;

/**
 *
 * @web http://java-buddy.blogspot.com/
 */
public class JFrameWin extends JFrame{
    
    public JFrameWin(){
        
        final JPanel jPanel = new JPanel();
        
        this.setTitle("java-buddy.blogspot.com");
        this.setSize(500, 400);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         
        JButton buttonExit = new JButton(" Exit ");
        buttonExit.addActionListener(new ActionListener(){
 
            @Override
            public void actionPerformed(ActionEvent ae) {
                System.exit(0);
            }
        });
        
        final JRadioButton jRadioButtonA = new JRadioButton("NORMAL");
        final JRadioButton jRadioButtonB = new JRadioButton("POPUP");
        final JRadioButton jRadioButtonC = new JRadioButton("UTILITY");

        ActionListener radioButtonActionListener = new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent ae) {
                
                String cmd = ae.getActionCommand();

                JFrame newFrame =new JFrame();  
                newFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                newFrame.setSize(300,200);
                newFrame.setTitle(cmd);
                
                if(cmd == "NORMAL"){
                    newFrame.setType(Type.NORMAL);
                }else if(cmd == "POPUP"){
                    newFrame.setType(Type.POPUP);
                }else if(cmd == "UTILITY"){
                    newFrame.setType(Type.UTILITY);
                }
                
                newFrame.setVisible(true); 

            }
            
        };
        
        jRadioButtonA.addActionListener(radioButtonActionListener);
        jRadioButtonB.addActionListener(radioButtonActionListener);
        jRadioButtonC.addActionListener(radioButtonActionListener);
        
        ButtonGroup buttonGroup  = new ButtonGroup();
        buttonGroup.add(jRadioButtonA);
        buttonGroup.add(jRadioButtonB);
        buttonGroup.add(jRadioButtonC);
        
        Box verticalBox = Box.createVerticalBox();
        verticalBox.add(jRadioButtonA);
        verticalBox.add(jRadioButtonB);
        verticalBox.add(jRadioButtonC);
        
        jPanel.add(verticalBox);
        jPanel.add(buttonExit);
        
        this.add(jPanel);
        
    }
}