Java Swing - 如何在JList中为项目设置工具提示

import java.awt.FlowLayout;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;

public class Main {
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setLayout(new FlowLayout());
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    String[] selections = { "green", "red", "orange", "dark blue" };
    JList list = new JList(selections) {
      // This method is called as the cursor moves within the list.
      public String getToolTipText(MouseEvent evt) {
        // Get item index
        int index = locationToIndex(evt.getPoint());

        // Get item
        Object item = getModel().getElementAt(index);

        // Return the tool tip text
        return "tool tip for " + item;
      }
    };
    list.setSelectedIndex(1);
    System.out.println(list.getSelectedValue());
    frame.add(new JScrollPane(list));
    frame.pack();

    frame.setVisible(true);
  }
}