Java Swing JLinkButton draws a button like JLabel with blue color and underlined font on mouse hover. Disclaimer: inspired by a few others similar solutions.

JLinkButton.java

import java.awt.Color;
import java.awt.Cursor;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.font.TextAttribute;
import java.util.Map;

import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingConstants;
import javax.swing.WindowConstants;

/**
 * JLinkButton draws a button like JLabel. Default foreground color is blue and the text is underlined on mouse hover
 * (behaviour depends on {@link #underlineMode}). Shows the hand cursor.
 * 
 * @author xmedeko
 */
public class JLinkButton extends JButton {

	/**
	 * Type of underline mode.
	 */
	public enum UnderlineMode {
		NONE, ALWAYS, HOVER
	};

	private UnderlineMode underlineMode = UnderlineMode.HOVER;

	public JLinkButton() {
		super();
	}

	public JLinkButton(Action a) {
		super(a);
	}

	public JLinkButton(Icon icon) {
		super(icon);
	}

	public JLinkButton(String text, Icon icon) {
		super(text, icon);
	}

	public JLinkButton(String text) {
		super(text);
	}

	@Override
	protected void init(String text, Icon icon) {
		super.init(text, icon);

		setFocusPainted(false);
		setMargin(null);
		setContentAreaFilled(false);
		setBorderPainted(false);
		setBorder(BorderFactory.createEmptyBorder());
		setOpaque(false);
		setHorizontalAlignment(SwingConstants.LEFT);
		setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));

		setForeground(Color.BLUE);

		addMouseListener(new MouseAdapter() {
			@Override
			public void mouseEntered(MouseEvent e) {
				if (getUnderlineMode() == UnderlineMode.HOVER) {
					setUnderlineFont(true);
				}
			}

			@Override
			public void mouseExited(MouseEvent e) {
				if (getUnderlineMode() == UnderlineMode.HOVER) {
					setUnderlineFont(false);
				}
			}
		});
	}

	/**
	 * set or reset the underline font.
	 */
	protected void setUnderlineFont(boolean underline) {
		@SuppressWarnings("unchecked")
		Map<TextAttribute, Object> map = (Map<TextAttribute, Object>) getFont().getAttributes();
		if (underline) {
			map.put(TextAttribute.UNDERLINE, TextAttribute.UNDERLINE_ON);
		} else {
			map.remove(TextAttribute.UNDERLINE);
		}
		Font newFont = new Font(map);
		setFont(newFont);
	}

	/**
	 * @return underline mode
	 */
	public UnderlineMode getUnderlineMode() {
		return underlineMode;
	}

	/**
	 * Set underline mode.
	 * 
	 * @return this, just for fluent API.
	 */
	public JLinkButton setUnderlineMode(UnderlineMode underlineMode) {
		this.underlineMode = underlineMode;
		switch (underlineMode) {
		case ALWAYS:
			setUnderlineFont(true);
			break;
		case NONE:
			setUnderlineFont(false);
			break;
		case HOVER: // nothing
			break;
		}

		return this;
	}

	// test
	public static void main(String[] args) {
		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
		frame.setLayout(new FlowLayout());
		frame.add(new JLinkButton("Hover").setUnderlineMode(UnderlineMode.HOVER));
		frame.add(new JLinkButton("None").setUnderlineMode(UnderlineMode.NONE));
		frame.add(new JLinkButton("Always").setUnderlineMode(UnderlineMode.ALWAYS));
		JLinkButton disabled = new JLinkButton("Disabled");
		disabled.setEnabled(false);
		frame.add(disabled);

		frame.pack();
		frame.setVisible(true);
	}

}