In Java, a JScrollBar is a component that provides a way for the user to select a value within a range by dragging a thumb within a track. A JScrollBar can be added to a JScrollPane to allow scrolling of the contents in the viewport of the scroll pane.

Here's a basic example that demonstrates how to create a JScrollBar:

JScrollBar scrollBar = new JScrollBar();

This creates a horizontal JScrollBar with default minimum and maximum values (0 and 100, respectively).

To set the minimum and maximum values for the JScrollBar, you can use the setMinimum and setMaximum methods, respectively:

scrollBar.setMinimum(0);
scrollBar.setMaximum(200);

To set the orientation of the JScrollBar, you can use the setOrientation method:

scrollBar.setOrientation(JScrollBar.VERTICAL); // or JScrollBar.HORIZONTAL

To add the JScrollBar to a JScrollPane, you can create a new JScrollPane and pass the component you want to scroll as a parameter to the constructor. Then, call the setVerticalScrollBar or setHorizontalScrollBar method to set the JScrollBar for the appropriate direction. For example:

JTextArea textArea = new JTextArea();
JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setVerticalScrollBar(scrollBar);

This creates a new JScrollPane that contains a JTextArea and uses the JScrollBar for vertical scrolling. You can also set the JScrollBar for horizontal scrolling by calling the setHorizontalScrollBar method instead of setVerticalScrollBar.

Finally, you can use the getModel method to get the BoundedRangeModel that controls the state of the JScrollBar. You can add a ChangeListener to this model to listen for changes to the scroll position. For example:

BoundedRangeModel model = scrollBar.getModel();
model.addChangeListener(e -> {
    int value = model.getValue();
    // Do something with the new scroll position
});