import javax.swing.*;
import java.awt.event.*;
class Win extends JFrame implements ActionListener
{ 
    JButton jButton1;
    JTextField jText_number1;
    JLabel jLabel1,jLabel2,jLabel3;
    public Win()
    {
        setLayout(null);
        setTitle("ƽ");
        jButton1 = new JButton("   ");
        jText_number1 = new JTextField();
        jLabel1 = new JLabel("һ");
        jLabel2 = new JLabel("");
        jLabel3 = new JLabel();
        jButton1.setBounds(120, 78, 83, 25);
        jLabel1.setBounds(15, 19, 99, 26);
        jLabel2.setBounds(44, 56, 50, 22);
        jLabel3.setBounds(96, 52, 96, 27);
        jText_number1.setBounds(123, 14, 83, 32);
        jButton1.addActionListener(this);
        add(jLabel1);
        add(jLabel2);
        add(jLabel3);
        add(jText_number1);
        add(jButton1);
        setBounds(200, 200, 250, 150);
        validate();
        setVisible(true);   
    }
    public void actionPerformed(ActionEvent e)
    {
        double number = 0;
        try {
              number = Double.valueOf(jText_number1.getText()).doubleValue();
              jLabel3.setText("" + Math.sqrt(number));
        } 
        catch (NumberFormatException event)
        {
 JOptionPane.showMessageDialog(this,"ַ","Ի",
JOptionPane.WARNING_MESSAGE);
        }
    }
}
class JOptionPane_Test_jButton1_actionAdapter
{
    public static void main(String args[])
    {
        Win ta = new Win();
    }
}
