How can we set the background color to a JPanel in Java?

In this article, we will learn to set the background color of a JPanel in Java. When designing GUIs in Swing, changing the background color of panels is important for creating visually appealing applications.

What is a JPanel?

A JPanel is a container, and it is an invisible component in Java. The FlowLayout is a default layout for a JPanel. We can add most of the components, like buttons, text fields, labels, tables, lists, trees, etc., into a JPanel.

Syntax

The following is the syntax for JPanel initialization:

JPanel panel = new JPanel();

Methods

The important methods of JPanel are:

• getAccessibleContext()
  
• getUI()
  
• setUI()
  
• updateUI()

Setting Background Color on JPanel

We can set a background color to a JPanel by using the setBackground() method. The following are the steps for setting the background color of a JPanel in Java:

Class Definition & Imports

The javax.swing.* provides Swing components (JFrame, JPanel, etc.) while the java.awt.* provides AWT classes (Color, layout managers) and the class extends JFrame to create a window.

import java.awt.*;
import javax.swing.*;
public class JPanelBackgroundColorTest extends JFrame {

Instance Variable & Constructor Setup

Declares a JPanel, which will serve as the main container. The constructor creates the JFrame window with the title "JPanelBackgroundColor Test".

private JPanel panel;
public JPanelBackgroundColorTest() {
        setTitle("JPanelBackgroundColor Test");

Panel Creation and Configuration

Creates a new panel with the default FlowLayout, then adds a label to the panel and sets its background color to green using the setBackground() method.

panel = new JPanel();
panel.add(new JLabel("Welcome to Tutorials Point"));
panel.setBackground(Color.green);

Adding Panel to Frame

Adds the panel to the center region of the frame using the BorderLayout.

add(panel, BorderLayout.CENTER);

Main Method

The main method launches the application by creating an object of JPanelBackgroundColorTest.

public static void main(String args[]) {
        new JPanelBackgroundColorTest();
}

Example

Below is an example of setting the background color to a JPanel in Java:

import java.awt.*
import javax.swing.*;
public class JPanelBackgroundColorTest extends JFrame {
   private JPanel panel;
   public JPanelBackgroundColorTest() {
      setTitle("JPanelBackgroundColor Test");
      panel = new JPanel();
      panel.add(new JLabel("Welcome to Tutorials Point"));
      panel.setBackground(Color.green);
      add(panel, BorderLayout.CENTER);
      setSize(375, 250);
      setLocationRelativeTo(null);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setVisible(true);
   }
   public static void main(String args[]) {
      new JPanelBackgroundColorTest();
   }
}

Output