code: package gui;
  
  import javax.swing.*;
  import javax.swing.plaf.*;
  import java.awt.event.*;
  import java.awt.*;
  
  public class TooltipInSwing extends JFrame {
   public TooltipInSwing() {
          super("TooltipInSwing");
          setSize(400, 300);
          getContentPane().setLayout(new FlowLayout());
  
          // globally
          UIManager.put("ToolTip.font",
             new FontUIResource("SansSerif", Font.BOLD, 18));
          JButton b1 = new JButton("tooltip 1");
          b1.setToolTipText("tool tip sansserif bold");
  
          getContentPane().add(b1);
  
          // only one
          String html =
              "<html><p><font color=\"#800080\" " +
              "size=\"4\" face=\"Verdana\">tool tip verdana" +
              "</font></p></html>";
          JButton b2 = new JButton("tooltip 2");
          b2.setToolTipText(html);
  
          getContentPane().add(b2);
  
          WindowListener wndCloser = new WindowAdapter(){
              public void windowClosing(WindowEvent e) {
                  System.exit(0);
                  }
              };
          addWindowListener(wndCloser);
          setVisible(true);
      }
  
      public static void main(String args[]){
       new TooltipInSwing();
       }
  }