Java Swing - 如何关闭一个JFrame而不关闭另一个...

import java.awt.Dimension;
import java.awt.Toolkit;

import javax.swing.JFrame;

public class Main {
  public static void main(String args[]) {
    JFrame frame = new JFrame();

    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();

    int width = (int) screenSize.getWidth();
    int height = (int) screenSize.getHeight();
    Dimension newDim = new Dimension(width, height - 40);

    frame.setSize(newDim);

    frame.setVisible(true); // FIRST visible = true
    frame.setResizable(false); // THEN resizable = false
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}