Create BigDecimal input field via DecimalFormat
import java.awt.FlowLayout; import java.math.BigDecimal; import java.text.DecimalFormat; import javax.swing.JFormattedTextField; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JTextField; import javax.swing.text.DefaultFormatter; import javax.swing.text.NumberFormatter; public class Main extends JFrame { public Main() { super("JButton"); setDefaultCloseOperation(EXIT_ON_CLOSE); setLayout(new FlowLayout()); JLabel nameLabel = new JLabel("Value:"); /* www.j a va 2 s. com*/ JFormattedTextField name = new JFormattedTextField(new BigDecimal(123.123)); DefaultFormatter fmt = new NumberFormatter(new DecimalFormat("#.0###############")); fmt.setValueClass(name.getValue().getClass()); JTextField text = new JTextField("Click here to see the validation result"); getContentPane().add(nameLabel); getContentPane().add(name); getContentPane().add(text); } public static void main(String[] args) { Main frame = new Main(); frame.pack(); frame.setVisible(true); } }