Calcular ecuacion de segundo grado en java

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/**
 *
 * @author rb34
 */

//import java.awt.*;

import java.awt.Color;
import javax.swing.*;
public class ecuacion  extends JFrame{
    // static JFrame ventana = new JFrame("ventana");
    static JButton procesar = new JButton();
    static JButton borrar = new JButton();

    static JLabel a = new JLabel("a");
    static JLabel b = new JLabel("b");
    static JLabel c = new JLabel("c");

    static JLabel x = new JLabel("x");
    static JLabel y = new JLabel("y");

    static JTextField texta = new JTextField();
    static JTextField textb = new JTextField();
    static JTextField textc = new JTextField();

    static JTextField textx = new JTextField();
    static JTextField texty = new JTextField();
    public ecuacion(){
        initComponents();
    }

     private void initComponents(){
        this.setTitle("ecuacion2");
        this.setSize(500, 160);
        this.setResizable(false);
        this.setLayout(null);
        //this.setBackground(Color.red);
        procesar.setLabel("procesar");
        procesar.setBounds(10, 80, 100, 30);
        procesar.setBackground(Color.blue);
        add(procesar);
       
        borrar.setLabel("borrar");
        borrar.setBounds(300, 80, 100, 30);
        borrar.setBackground(Color.CYAN);
        add(borrar);

        a.setBounds(10, 10, 10, 20);
        texta.setBounds(30, 10, 50, 20);
        add(a);
        add(texta);
        b.setBounds(10, 30, 10, 20);
        textb.setBounds(30, 30, 50, 20);
        add(b);
        add(textb);
        c.setBounds(10, 50, 10, 20);
        textc.setBounds(30, 50, 50, 20);
        add(c);
        add(textc);

        x.setBounds(300, 10, 10, 20);
        textx.setBounds(310, 10, 50, 20);
        add(x);
        add(textx);


        y.setBounds(300, 30, 10, 20);
        texty.setBounds(310, 30, 50, 20);
        add(y);
        add(texty);



        this.setVisible(true);
    }
     public static void main(String args[]){
         ecuacion demo =new ecuacion();
     }



}


class  evento2 implements ActionListener{

    ecuacion local;
    int a,b,c;
    double z;

    public evento2( ecuacion para){
        local = para;
     }

    public void actionPerformed(ActionEvent evento2){
        if (evento2.getSource()==local.procesar){
            a = Integer.parseInt(local.texta.getText());
            b = Integer.parseInt(local.textb.getText());
            c = Integer.parseInt(local.textc.getText());
           
            //z=Math.sqrt((b*b)+(-4*a*c));
            local.textx.setText(" "+((-b+Math.sqrt((b*b)+(-4*a*c)))/(2*a)));
            local.texty.setText(" "+((-b-Math.sqrt((b*b)+(-4*a*c)))/(2*a)));
        }
        if (evento2.getSource()==local.borrar){
            local.texta.setText(null);
            local.textb.setText(null);
            local.textc.setText(null);
            local.textx.setText(null);
            local.texty.setText(null);
           
        }
    }

}