title: JTextField: How to validate number input in JTextField
body: <p>How to validate a textfield to enter only 10 digits mobile number in Swing?</p>
  
  <p>I have three text field. </p>
  
  <ol>
  <li>For name</li>
  <li>For Contact</li>
  <li>No. For Email</li>
  </ol>
  
  <p>I want to click on submit button then check name, contact and email right or wrong. I also want to set limit of character</p>
  
  <pre><code>import java.awt.GridBagConstraints;
  import java.awt.GridBagLayout;
  import java.awt.Insets;
  import javax.swing.JFrame;
  import javax.swing.JLabel;
  import javax.swing.JTextField;
  import javax.swing.JButton;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  
  class UpDateProfile extends JFrame implements ActionListener
  {
      JLabel name_lbl,email_lbl,contact_lbl;
      JTextField name_text,email_text,contact_text;
      JButton submit_btn;
      public UpDateProfile()
      {
              super("Velidation demo");
  
              setSize(650,450);
              setLocation((int)Toolkit.getDefaultToolkit().getScreenSize().getWidth()/2-325,(int)Toolkit.getDefaultToolkit().getScreenSize().getHeight()/2-225);
              setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
              setLayout(new GridBagLayout());
              setResizable(false);
  
              GridBagConstraints gbc1 = new GridBagConstraints();
              gbc1.insets = new Insets(5,3,5,3);
  
          name_lbl = new JLabel("Name :");
          gbc1.gridx = 0;
          gbc1.gridy = 0;
          gbc1.ipadx = 0;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 1;
          gbc1.fill = GridBagConstraints.HORIZONTAL;
          gbc1.anchor = GridBagConstraints.WEST;
          add(name_lbl,gbc1);
  
          name_text = new JTextField(30);
          gbc1.gridx = 1;
          gbc1.gridy = 0;
          gbc1.ipadx = 0;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 3;
          gbc1.fill = GridBagConstraints.HORIZONTAL;
          gbc1.anchor = GridBagConstraints.WEST;
          add(name_text,gbc1);
  
          email_lbl = new JLabel("E-mail :");
          gbc1.gridx = 0;
          gbc1.gridy = 1;
          gbc1.ipadx = 0;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 1;
          gbc1.fill = GridBagConstraints.HORIZONTAL;
          gbc1.anchor = GridBagConstraints.WEST;
          add(email_lbl,gbc1);
  
          alt_email_text = new JTextField(30);
          gbc1.gridx = 1;
          gbc1.gridy = 1;
          gbc1.ipadx = 0;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 3;
          gbc1.fill = GridBagConstraints.HORIZONTAL;
          gbc1.anchor = GridBagConstraints.WEST;
          add(alt_email_text,gbc1);
  
          contact_lbl = new JLabel("Contact No. :");
          gbc1.gridx = 0;
          gbc1.gridy = 2;
          gbc1.ipadx = 0;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 1;
          gbc1.fill = GridBagConstraints.HORIZONTAL;
          gbc1.anchor = GridBagConstraints.WEST;
          add(contact_lbl,gbc1);
  
          contact_text = new JTextField(10);
          gbc1.gridx = 1;
          gbc1.gridy = 2;
          gbc1.ipadx = 0;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 1;
          gbc1.fill = GridBagConstraints.HORIZONTAL;
          gbc1.anchor = GridBagConstraints.WEST;
          add(contact_text,gbc1);
  
          submit_btn = new JButton("Submit");
          submit_btn.addActionListener(this);
          gbc1.gridx = 2;
          gbc1.gridy = 7;
          gbc1.ipadx = 10;
          gbc1.ipady = 0;
          gbc1.gridheight = 1;
          gbc1.gridwidth = 2;
          gbc1.anchor = GridBagConstraints.CENTER;
          add(submit_btn,gbc1);
      }
      public void actionPerformed(ActionEvent ae)
      {
          if(ae.getSource()==submit_btn)
          {
  
          }
      }
  }
  </code></pre>