Java Swing provides Icon interface and any class which implements it is an icon & this way we can create custom icon. The Icon interface will ask you to implement three methods to decide the size of the icon and to perform icon drawing. In this example, we will create rectangle icon and use it with the JLabel component.
This example has four JLabels in it and a FlowLayout Manager is taking care of laying out these labels. Each label uses a unique border to draw around it. Since JLabel is a component, one can apply the same technique for other components as well. For example, a JTextField can use same technique to draw the border. Now, we can have a look at the Bevel Raised border in the picture above and the JLabel looks like a button, right? But it is not. We also set a Font for all the JLabels in this example.