JTextField Validation in java swing

In this tutorial, you will learn how to validate jtextfield in java swing. Here we have created a textfield on frame and allowed the user to enter. If the user enter characters or symbols or special character, it cannot be inserted in the textfield, the textfield will not respond to any character, it only accepts numbers.

Example:

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

class TextValidation extends JFrame{
JTextField text;
JLabel label;
JPanel p;
TextValidation(){
text=new JTextField(15);
label=new JLabel("Enter number:");
p=new JPanel();
p.add(label);
p.add(text);
text.addKeyListener(new KeyAdapter(){
            public void keyPressed(KeyEvent e){

                char ch = e.getKeyChar();
                if(Character.isDigit(ch)){
                }
                else{
                    JOptionPane.showMessageDialog(null, "Only numbers are allowed!");
                    text.setText(" ");
                }
            }
});
add(p);
setVisible(true);
setSize(300,100);
}
public static void main(String[]args){
TextValidation v=new TextValidation();
}
}

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