Java Multiplication of two 100 digits number

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

class SwingMultiplication
{
    public static void main(String[] args) 
    {
        JFrame f=new JFrame();
        f.setLayout(null);
        JLabel l1=new JLabel("Number 1");
        JLabel l2=new JLabel("Number 2");
        JLabel l3=new JLabel("Result");
        final JTextField text1=new JTextField(20);
        final JTextField text2=new JTextField(20);
        final JTextField text3=new JTextField(20);
        JButton b=new JButton("Calculate");
        l1.setBounds(10,10,100,20);
        text1.setBounds(120,10,100,20);

        l2.setBounds(10,40,100,20);
        text2.setBounds(120,40,100,20);

        l3.setBounds(10,70,100,20);
        text3.setBounds(120,70,100,20);

        b.setBounds(120,100,100,20);
        f.add(l1);
        f.add(text1);
        f.add(l2);
        f.add(text2);
        f.add(l3);
        f.add(text3);
        f.add(b);
        f.setVisible(true);
        f.setSize(400,200);
        b.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
            String v1=text1.getText();
            String v2=text2.getText();
            BigInteger big1=new BigInteger(v1);
            BigInteger big2=new BigInteger(v2);
            BigInteger res=big1.multiply(big2);
            text3.setText(res.toString());
            }
        });
    }
}