What is the Difference Between Panel and Frame in Java

The main difference between Panel and Frame in Java is that the Panel is an internal region to a frame or another panel that helps to group multiple components together while a Frame is a resizable, movable independent window with a title bar which contains all other components.

Java is a general-purpose, high-level programming language that is designed to have a minimum amount of dependencies as possible. The Java source code is converted into an intermediate code called a bytecode. Any platform that has a JVM can executed the bytecode. Thus, it is a platform independent language. One main advantage of Java is that it provides APIs to develop powerful Graphical User Interfaces (GUIs). AWT, which stands for Abstract Window Toolkit, is one such API. Panel and Frame are two components in AWT.

Key Areas Covered

1. What is Panel
     – Definition, Functionality
2. What is Frame
     – Definition, Functionality
3. What is the Relationship Between Panel and Frame in Java
     – Outline of Association
4. What is the Difference Between Panel and Frame in Java
     – Comparison of Key Differences

Key Terms

API, AWT, GUI, Frame, JVM, Panel

What is Panel

Panel is a component that allows placing multiple components on it. It is created using the Panel class. This class inherits the Container class. Refer the below program. 

Figure 1: Simple GUI application

In the above program, f is a Frame object while the panel is a Panel object. The panel object is placed according to the specified location using setBounds method. The color of the panel is Gray. The b1 is a button object that is placed according to the specified location. The color of the button is blue. Then, b1 button is added to the panel and the panel is added to the Frame f1. Finally, the frame f1 is visible with the components.

What is Frame

Frame is a component that works as the main top-level window of the GUI application. It is created using the Frame class. For any GUI application, the first step is to create a frame. There are two methods to create a frame: by extending the Frame class or by creating an object of Frame class.

According to the above program (Figure 1), f is a Frame object. Other GUI components are added to it. Finally, the frame is displayed.  The frame is a resizable and a movable window. It has the title bar. The default visibility of a Frame is hidden. The programmer has to make it visible by using setVisible method and providing the value “true” to it.

Relationship Between Panel and Frame in Java

• Panel requires a Frame to display it. A frame can consist of a panel or a set of panels.

Difference Between Panel and Frame in Java

Definition

Panel in Java is an AWT component which represents a simple container that can attach other GUI components including other panels. Frame in Java is an AWT component which is a top level window with border and title. Thus, this explains the fundamental difference between Panel and Frame in Java.

Class Hierarchy

The main difference between Panel and Frame in Java is that the Panel is a subclass of Container while Frame is a subclass of Window. Meanwhile, Window is a subclass of Container.

Class Declaration

Title Bar

Moreover, the Panel does not have a title bar. Since Frame is a top-level window, it has a title bar.

Border

Another difference between Panel and Frame in Java is that the  Panel does not have a border while Frame has a border.

Adding to Another

Moreover, it is possible to add another panel to an existing panel. However, it is not possible to add a frame to another frame. Hence, this is also a significant difference between Panel and Frame in Java.

Dependency

Besides, Panel depends on the Frame. However, Frame is an independent output window.

Default Layout Manager

Panel uses FlowLayout as default layout manager while Frame uses BorderLayout as default layout manager. This is another difference between Panel and Frame in Java.

Conclusion

In brief, Panel and Frame are two components in AWT. The main difference between Panel and Frame in Java is that the Panel is an internal region in a frame or another panel that helps to group multiple components together while a Frame is a resizable, movable independent window with a title bar which contains all other components.

Reference:

1. “AWT Panel Class.” Www.tutorialspoint.com, Available here.
2. “AWT Frame Class.” Www.tutorialspoint.com, Available here.