1)Frame1.java:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Frame1{
  public static void main(String[] args){
    Frame1 sr = new Frame1();
  }

  public Frame1(){
    final JFrame frame = new JFrame("Frame1");
    frame.setLayout(null);
    JButton b = new JButton("Click");
    b.setBounds(20,20,80,20);
    frame.add(b);
    frame.setSize(300,100);
    frame.setVisible(true);

    b.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent e){
      Frame2 f=new Frame2();
      frame.setVisible(false);
      f.setVisible(true);
      f.setSize(300,100);
      }
    });
  }
}

2)Frame2.java:

import javax.swing.*;
class Frame2 extends JFrame
{
    Frame2()
    {
    setTitle("Frame2");

    add(new JLabel("Hello World"));
    setVisible(true);
    pack();
    }
}