Java Frame Class Example

JFRAME

Java Swing Tutorial Explaining the JFrame class. The components added to the frame are referred to as its contents; these are managed by the contentPane. To add a component to a JFrame, we must use its contentPane instead.JFrame is a Window with border, title and buttons. When JFrame is set visible, an event dispatching thread is started. JFrame objects store several objects including a Container object known as the content pane. To add a component to a JFrame, add it to the content pane.

JFrame Features

It’s a window with title, border, (optional) menu bar and user-specified components.
It can be moved, resized, iconified.
It is not a subclass of JComponent.
Delegates responsibility of managing user-specified components to a content pane, an instance of JPanel.

Centering JFrame’s

By default, a Jframe is displayed in the upper-left corner of the screen. To display a frame
at a specified location, you can use the setLocation(x, y) method in the JFrame class. This
method places the upper-left corner of a frame at location (x, y).

The Swing API keeps improving with abstractions such as the setDefaultCloseOperation method
for the JFrame

Crating a JFrame Window

Step 1: Construct an object of the JFrame class.

Step 2: Set the size of the Jframe.

Step 3: Set the title of the Jframe to appear in the title bar (title bar will be blank if no title is set).

Step 4: Set the default close operation. When the user clicks the close button, the program stops running.

Step 5: Make the Jframe visible.

How to position JFrame on Screen?

frame.setLocationRelativeTo( null );

JFRAME SOURCE CODE

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

public class JFrameDemo {

	public static void main(String s[]) {
		JFrame frame = new JFrame("JFrame Source Demo");
		// Add a window listner for close button
		frame.addWindowListener(new WindowAdapter() {

			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		// This is an empty content area in the frame
		JLabel jlbempty = new JLabel("");
		jlbempty.setPreferredSize(new Dimension(175, 100));
		frame.getContentPane().add(jlbempty, BorderLayout.CENTER);
		frame.pack();
		frame.setVisible(true);
	}
}

Output

Download jFrame Source Code

JAVA JFRAME HIERARCHY

javax.swing
Class JFrame
java.lang.Object
java.awt.Component
java.awt.Container
java.awt.Window
java.awt.Frame
javax.swing.JFrame
All Implemented Interfaces:
Accessible, ImageObserver, MenuContainer, RootPaneContainer, Serializable, WindowConstants

JFRAME CONSTRUCTOR

JFrame()
Constructs a new frame that is initially invisible.

JFrame(GraphicsConfiguration gc)
Creates a Frame in the specified GraphicsConfiguration of a screen device and a blank title.

JFrame(String title)
Creates a new, initially invisible Frame with the specified title.

JFrame(String title, GraphicsConfiguration gc)
Creates a JFrame with the specified title and the specified GraphicsConfiguration of a screen device.

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