Set password length for JPasswordField

Complete source code below will show you, how you can set password length in JPasswordField. In source code below, we will enable user to enter only password that contains five characters.After that it will disable password field. User can delete entered password by press 'Backspace' key.

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COMPLETE SOURCE CODE FOR : SetPasswordLength.java
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import javax.swing.*;

import javax.swing.event.*;

import java.awt.event.*;

import java.awt.FlowLayout;

public class SetPasswordLength implements CaretListener
{
//Create password field
JPasswordField passwordField=new JPasswordField(12);

JLabel label=new JLabel("Press Backspace to delete password");

JFrame frame;

//Create key listener that will listen when someone press Backspace key
KeyListener kl=new KeyAdapter()
{
 public void keyPressed(KeyEvent event)
 {
  if(event.getKeyCode()==KeyEvent.VK_BACK_SPACE)
  {
   passwordField.setEditable(true);
  
   label.show(false);
  
   frame.repaint();
  
   frame.validate();
  }
 }
};

public SetPasswordLength()
{
 label.show(false);

 passwordField.addCaretListener(this);

 passwordField.addKeyListener(kl);

 frame=new JFrame("Set password length");

 frame.setLayout(new FlowLayout());

 frame.add(passwordField);

 frame.add(label);

 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 frame.setSize(500,100);

 frame.setVisible(true);
}

//Listen for changes in the caret position
public void caretUpdate(CaretEvent event)
{
 int passwordLength=passwordField.getText().length();

 //If password length equal to five characters, password field will uneditable
 //You can change to any password length that you want by change 5 to any other value
 if(passwordLength==5)
 {
  passwordField.setEditable(false);
 
  label.show(true);
 
  frame.repaint();
 
  frame.validate();
 }
}

public static void main(String[]args)
{
 SetPasswordLength spl=new SetPasswordLength();
}
}

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JUST COMPILE AND EXECUTE IT
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