//Write an application that accepts a user\'s password from an input dialog. //I

Question

//Write an application that accepts a user's password from an input dialog.
//If the entered password is less than six characters, more than 10 characters, or does not contain at least one letter and one digit, prompt the user again.
// When the user's entry meets all the password requirements, prompt the user to reenter the password,
//and do not let the user continue until the second password matches the first one. Save the file as Password.java.





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

import java.util.Scanner;
class namematch{
public static void main(String[] args){
String aName="";
String anotherName="";
char charBeingChecked;
boolean letterPresent = false;

boolean digitPressent = false;

char charChecked;

int len=aName.length();
aName= JOptionPane.showInputDialog("ENter");



while (( len<6 || len>11) || ! (Character.isLetterOrDigit(aName.charAt(len))) )

{aName= JOptionPane.showInputDialog("Enter the Correct Format");
}






if ((len>=6|| len<=11) || (Character.isLetterOrDigit(aName.charAt(len))) )
do
{
anotherName= JOptionPane.showInputDialog("Re-enter to match.");
}
while (!(aName.equals(anotherName)));
if (aName.equals(anotherName))
{
JOptionPane.showMessageDialog(null,"Accepted");
}

}
}


}

Explanation / Answer

for this Java program to work it needs to be saved in a file called PasswordDialog.java //Imports are listed in full to show what's being used //could just import javax.swing.* and java.awt.* etc.. import javax.swing.JFrame; import javax.swing.JOptionPane; import javax.swing.JTextField; import javax.swing.JTextArea; import javax.swing.JPasswordField; import javax.swing.JPanel; import javax.swing.JLabel; import java.awt.GridLayout; import java.util.Arrays; import java.awt.EventQueue; public class PasswordDialog { //Note: Typically the main method will be in a //separate class. As this is a simple one class //example it's all in the one class. public static void main(String[] args) { //Use the event dispatch thread for Swing components EventQueue.invokeLater(new Runnable() { @Override public void run() { createGuiFrame(); } }); } //handles the creation of the JFrame and //all it's components private static void createGuiFrame() { JFrame guiFrame = new JFrame(); //make sure the program exits when the frame closes guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); guiFrame.setTitle("Dialog Box Example"); guiFrame.setSize(500,300); //This will center the JFrame in the middle of the screen guiFrame.setLocationRelativeTo(null); guiFrame.setVisible(true); //Using a JTextArea to diplay feedback //(i.e., the username and password entered JTextArea tracker = new JTextArea("Password Tracker:"); guiFrame.add(tracker); //Using a JPanel as the message for the JOptionPane JPanel userPanel = new JPanel(); userPanel.setLayout(new GridLayout(2,2)); JLabel usernameLbl = new JLabel("Username:"); JLabel passwordLbl = new JLabel("Password:"); JTextField username = new JTextField(); JPasswordField passwordFld = new JPasswordField(); userPanel.add(usernameLbl); userPanel.add(username); userPanel.add(passwordLbl); userPanel.add(passwordFld); //As the JOptionPane accepts an object as the message //it allows us to use any component we like - in this case //a JPanel containing the dialog components we want int input = JOptionPane.showConfirmDialog(guiFrame, userPanel, "Enter your password:" ,JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE); char[] correctPassword = {'a', 'P', 'a', 'S', 's', 'W', 'o', 'R', 'd'}; if (input == 0) //OK Button = 0 { tracker.append(" Username entered was: " + username.getText()); //Retrieve password char[] enteredPassword = passwordFld.getPassword(); tracker.append(" Password entered was: " + String.valueOf(enteredPassword)); if (Arrays.equals(correctPassword, enteredPassword)) { tracker.append(" The password entered is correct!"); } else { tracker.append(" Call security - it's an imposter!"); } //Note: best practice is to zero out the array //that contains the password. (Bit silly here //as I'm printing the password to show how it's retrived //but keep it in mind when using JPasswordFields.) Arrays.fill(enteredPassword, '0'); } else { //either the cancel button or the 'x' //has been pressed tracker.append(" Dialog cancelled.."); } } }

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