What are the differences between a JScrollBar and a JScrollPane in Java?

In this article, we will learn about the differences between a JScrollBar and a JScrollPane in Java. A JScrollBar is a component, and it doesn't handle its own events whereas a JScrollPane is a Container and it handles its own events and performs its own scrolling. A JScrollBar cannot have a JScrollPane whereas a JScrollPane can have a JScrollBar.

JScrollBar

The object of the JScrollBar class is used to add horizontal and vertical scrollbar which allow the user to select items between a specified minimum and maximum values. A JScrollBar class is an implementation of a scrollbar and inherits the JComponent class.

The following are primary features of JScrollBar:

• Can be horizontal or vertical.
• Requires manual adjustment of the view when scrolled.
• Useful when you need custom scrolling behavior.

Initialization of JScrollBar:

JScrollBar scrollBar = new JScrollBar(int orientation, int value, int extent, int min, int max);

The following are the parameters for JScrollBar in Java:

• orientation: JScrollBar.HORIZONTAL or JScrollBar.VERTICAL
  
• value: Initial position of the scrollbar thumb
  
• extent: Size of the visible area (viewport)
  
• min & max: Minimum and maximum scrollable range

When to Use JScrollBar?

For the following scenarios, we can use the JScrollBar in Java:

• When you need custom scrolling logic for the scrollbar, e.g., a volume slider.
  
• When dealing with non-standard scrollable elements.
  
• When you need precise control over scrolling behavior.

Example of JScrollBar

Below is an example of JScrollBar showing a scrollbar on a Swing GUI in Java:

import javax.swing.*;
import java.awt.*;
public class JScrollBarTest extends JFrame{
   JScrollBarTest() {
      setTitle("JScrollBar Test");
      JScrollBar jsb = new JScrollBar();
      setLayout(new FlowLayout());
      add(jsb);
      setSize(350, 275);
      setLocationRelativeTo(null);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setVisible(true);
   }
   public static void main(String args[]) {
      new JScrollBarTest();
   }
}

Output

JScrollPane

A JSrollPane is used to make a scrollable view of a component. A scroll pane is an object of the JScrollPane class, which extends the JComponent class. When screen size is limited, we use a scroll pane to display a large component or a component whose size can change dynamically.

The important methods of the JScrollPane class are:

• setColumnHeaderView()
• setRowHeaderView()
• setViewportView()

Initialization of JScrollPane:

JScrollPane scrollPane = new JScrollPane(Component view);

view: The component to be scrolled (e.g., JTextArea, JTable).

When to Use JScrollPane?

For the following scenarios, we can use the JScrollPane in Java:

• When you need automatic scrolling for large components.
  
• For tables, text areas, or panels that may overflow.
  
• When you want built-in mouse wheel support.

Example

Below is an example of JScrollPane showing a scrollbar on a Swing GUI in Java:

import javax.swing.*;
import java.awt.*;
public class JScrollPaneTest extends JFrame {
   JScrollPaneTest() {
      setTitle("JScrollPane Test");
      JPanel panel = new JPanel();
      panel.setLayout(new BorderLayout());
      JScrollPane jsp = new JScrollPane(panel, ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,          ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
      add(jsp);
      setSize(350, 275);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      setLocationRelativeTo(null);
      setVisible(true);
   }
   public static void main(String[] args) {
      new JScrollPaneTest();
   }
}

Output

Difference Table

The following are the key differences between JScrollBar and JScrollPane in Java: