Check out example codes for "look and feel java". It will help you in understanding the concepts better.

Code Example 1

UIManager.setLookAndFeel("lookandfeel");

Code Example 2

try {
			UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
		} catch (Throwable e) {
			e.printStackTrace();
		}

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