How to Create JTextField Validation in java swing

JTextField can allow numbers, characters, and special characters. Validating user input that is typed into a JTextField can be difficult, especially if the input string must be converted to a numeric value such as an int.

package javaGuiProject;

import java.awt.event.KeyAdapter;

import java.awt.event.KeyEvent;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JOptionPane;

import javax.swing.JPanel;

import javax.swing.JTextField;

public 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();

}

}