Java Swing - JPanel With Examples

JPanel, a part of the Java Swing package, is a container that can store a group of components. The main task of JPanel is to organize components, various layouts can be set in JPanel which provide better organization of components, however, it does not have a title bar.

Constructors of JPanel 

1. JPanel(): creates a new panel with a flow layout
2. JPanel(LayoutManager l): creates a new JPanel with specified layoutManager
3. JPanel(boolean isDoubleBuffered): creates a new JPanel with a specified buffering strategy
4. JPanel(LayoutManager l, boolean isDoubleBuffered): creates a new JPanel with specified layoutManager and a specified buffering strategy

Commonly used Functions of JPanel 

1. add(Component c): Adds a component to a specified container
2. setLayout(LayoutManager l): sets the layout of the container to the specified layout manager
3. updateUI(): resets the UI property with a value from the current look and feel.
4. setUI(PanelUI ui): sets the look and feel of an object that renders this component.
5. getUI(): returns the look and feel object that renders this component.
6. paramString(): returns a string representation of this JPanel.
7. getUIClassID(): returns the name of the Look and feel class that renders this component.
8. getAccessibleContext(): gets the AccessibleContext associated with this JPanel.

Let us take a sample program in order to illustrate the use of JPanel class by appending sequential execution snapshots of outputs justifying the below program sets as follows:

Example:

Output: 

Example 2:

Output:

 Example 3:

Output:

Henceforth, we are successfully able to generate buttons in our panel. 

Note: In the previous Program, border layout and Box Layout are used. Different other layouts can be used to organize the components in a definite pattern, such as card layout, grid layout, etc.