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

class Program extends JFrame implements KeyListener {

	JFrame ablak;
	JButton gomb;
 
	public static void main(String args[]) {
		new Program();
	}
	Program() {
		gomb = new JButton("Teszt");
		add(gomb);
		setBounds(0,20,100,50);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		addKeyListener(this);
		setFocusable(true); //Szükséges a lenyomott billentyű figyeléséhez
		setVisible(true);
	}
	public void keyTyped(KeyEvent e) {
		char i = e.getKeyChar();
		String str = Character.toString(i);
		
		if(i == 'a')
			gomb.setText("a");
		if(i == 'b')
			gomb.setText("b");
		
	}
	public void keyReleased(KeyEvent e)	{}
	public void keyPressed(KeyEvent e)	{}

}