risolto cosi:
codice:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calcolatrice extends JFrame implements ActionListener{
    public static void main(String[] argv){
		//inizialize frame
        Calcolatrice mainApp = new Calcolatrice();
    }
    public Calcolatrice()
    {
		//set frame
        super("JTextArea Example");
		setResizable (false);
		pack();
        setBounds(0, 0, 300, 150);
        getContentPane().setLayout(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
		//add textarea
        textarea = new JTextArea();
        textarea.setBounds(0, 0, 294, 78);
		//add button
        button1 = new JButton("Copy Text Area to Console Window");
        button1.setBounds(0, 78, 294, 22);
		//add button
        button2 = new JButton("Copy Text Area to Console Window");
        button2.setBounds(0, 100, 294, 22);
		//add listener
        button1.addActionListener(this);
		button2.addActionListener(this);
		//add frame
        getContentPane().add(textarea);
        getContentPane().add(button1);
		getContentPane().add(button2);
        setVisible(true);
    }
    //eventi
    public void actionPerformed(ActionEvent e){
        if(e.getSource() == button1){System.out.println(textarea.getText());}
        if(e.getSource() == button2){System.out.println(textarea.getText());}
    }
    JButton   button1;
	JButton   button2;
    JTextArea textarea;
}