Duas casas depois da vírgula!

import java.text.NumberFormat;
import java.util.Locale;

import javax.swing.JFormattedTextField;
import javax.swing.JFrame;

public class Teste extends JFrame{


	public Teste() {
		
		NumberFormat numberFormat = NumberFormat.getInstance(new Locale("pt_BR"));
		numberFormat.setMaximumFractionDigits(2);
		JFormattedTextField jftf = new JFormattedTextField(numberFormat);
		jftf.setValue(new Double("1.34123123"));
		
		this.add(jftf);
		this.setDefaultCloseOperation(EXIT_ON_CLOSE);
		this.pack();
		this.setVisible(true);
	}
	
	public static void main(String[] args) {
		new Teste();
	}

}