Simple Example

import javax.swing.*;

public class FrameExample{
  public static void main(String[] args){
  JFrame frame = new JFrame("Frame in Java Swing");
  frame.setSize(400, 400);
  frame.setVisible(true);
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
}

Another Example

import java.awt.*;
    import javax.swing.*;
    class FrameExample 
    {
        public static void main(String[] args) 
        {
            JFrame f=new JFrame();
            f.setLayout(null);

            JLabel lab1=new JLabel("Name");
            JLabel lab2=new JLabel("Age");

            JTextField text1=new JTextField(20);
            JTextField text2=new JTextField(20);

            lab1.setBounds(10,10,100,20);
            text1.setBounds(120,10,100,20);

            lab2.setBounds(10,40,100,20);
            text2.setBounds(120,40,100,20);

            f.add(lab1);
            f.add(text1);
            f.add(lab2);
            f.add(text2);

            f.setVisible(true);
            f.setSize(300,150);
        }
    }

For more information, visit the following link:

Swing Tutorials