Java Swing Tutorial: How to Create a GUI in Java with Examples

The Java Swing library is built on top of the Java Abstract Widget Toolkit (AWT), an older, platform dependent GUI toolkit. You can use the Java GUI programming components like button, textbox, etc. from the library and do not have to create the components from scratch.

In this Java Swing tutorial, you will learn-

• What is Swing in Java?
• What is a Container Class?
• What is GUI in Java?
• Java GUI Example
• Java Layout Manager
• Java BorderLayout
• Java FlowLayout
• Java GridBagLayout

Java Swing class Hierarchy Diagram

All components in Java Swing are JComponent which can be added to container classes.
 

What is a Container Class?

Container classes are classes that can have other components on it. So for creating a Java GUI, we need at least one container object. There are 3 types of Java Swing containers.

1. Panel: It is a pure container and is not a window in itself. The sole purpose of a Panel is to organize the components on to a window.
2. Frame: It is a fully functioning window with its title and icons.
3. Dialog: It can be thought of like a pop-up window that pops out when a message has to be displayed. It is not a fully functioning window like the Frame.

Java GUI Example

Now in this Swing Java Tutorial, let's understand GUI with Java Swing examples.

Example: To learn Java GUI programming in this Java GUI tutorial
Step 1) Copy the following code into an editor

import javax.swing.*;
class gui{
    public static void main(String args[]){
       JFrame frame = new JFrame("My First GUI");
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       frame.setSize(300,300);
       JButton button = new JButton("Press");
       frame.getContentPane().add(button); // Adds Button to content pane of frame
       frame.setVisible(true);
    }
}

Step 2) Save, Compile, and Run the code.
Step 3) Now let's Add a Button to our frame.  Copy following code into an editor from given Java GUI Example

import javax.swing.*;
   class gui{
      public static void main(String args[]){
        JFrame frame = new JFrame("My First GUI");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300,300);
       JButton button1 = new JButton("Press");
       frame.getContentPane().add(button1);
       frame.setVisible(true);
     }
}

Step 4) Execute the code. You will  get a big button Step 5) How about adding two buttons? Copy the following code into an editor.

import javax.swing.*;
class gui{
      public static void main(String args[]){
           JFrame frame = new JFrame("My First GUI");
           frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
           frame.setSize(300,300);
          JButton button1 = new JButton("Button 1");
          JButton button2 = new JButton("Button 2");
          frame.getContentPane().add(button1);
          frame.getContentPane().add(button2);
          frame.setVisible(true);
     }
}

Step 6) Save , Compile , and Run the program.
Step 7) Unexpected output =? Buttons are getting overlapped.

Java Layout Manager

The Layout manager is used to layout (or arrange) the GUI java components inside a container.There are many layout managers, but the most frequently used are-

Java BorderLayout

A BorderLayout places components in up to five areas: top, bottom, left, right, and center. It is the default layout manager for every java JFrame

Java FlowLayout

FlowLayout is the default layout manager for every JPanel. It simply lays out components in a single row one after the other.