CODEWITHSUNDEEP
javaarraysswingif-statementjpasswordfield
Luke Yeh
Luke Yeh

Reputation: 1

JPasswordField Turning into String but cannot Compare

Hello what i am trying to do here is to recieve the password the User has entered then compare it with the correct password in a if statement.

public void actionPerformed(ActionEvent event)
{
    String UsersStoredPassword = "hello";
    String UsersEnteredPassword = new String(PasswordField.getPassword());
    String Message = "The Password You Have Entered Is Correct";
    String Message1 = "You Have Entered The Wrong Password";

    if (event.getSource() == PasswordField)
    {
        if (UsersEnteredPassword == UsersStoredPassword)
        {
            JOptionPane.showMessageDialog(null, Message);
        }
        else
        {
            JOptionPane.showMessageDialog(null, Message1);
        }

    }
}

However event thought the user typed in the correct password: "hello" it still shows message1: "You Have Entered The Wrong Password. I have tried doing this: 

public class TheHandler implements ActionListener
{
    public void actionPerformed(ActionEvent event)
    {

        String UsersStoredPassword = "hello";
        String UsersEnteredPassword = new String(PasswordField.getPassword());
        String Message = "The Password You Have Entered Is Correct";
        String Message1 = "You Have Entered The Wrong Password";

        if (event.getSource() == PasswordField)
        {
            JOptionPane.showMessageDialog(null, UsersEnteredPassword);
        }
    }
}

and it shows UsersEnteredPassword as typed inside.

Upvotes: 0

Views: 2172

Answers (3)

Reimeus
Reimeus

Reputation: 159844

You're comparing 2 Strings using the == operator which does not compare String content but this is not the real issue:

You've created a security vulnerability here.

Explanation: JPassword.getText was purposely deprecated to avoid using Strings in favor of using a char[] returned by getPassword.

When calling getText you get a String (immutable object) that may not be changed (except reflection) and so the password stays in the memory until garbage collected.

A char array however may be modified, so the password will really not stay in memory.

Use Array.equals instead

if (Arrays.equals(usersEnteredPassword.toCharArray()), 
      passwordField.getPassword()) {
      // password match!
}

Aside: Follow Java Naming conventions using a lowercase letter as a the initial letter for variable names as shown above. Read Naming Conventions

Upvotes: 4

Keerthivasan
Keerthivasan

Reputation: 12890

Strings shouldn't be compared with '=='. You should always check equality using .equals(Object) method for checking equality on any Objects. '==' is used to compare primitive datatype only, not Objects. '==' compares the equality of the physical memory address of the left and right operands. .equals(Object) checks whether both left and right operands are meaningfully equivalent. Hope this helps

Upvotes: 1

RamonBoza
RamonBoza

Reputation: 9038

if(UsersEnteredPassword == UsersStoredPassword){

to

if(UsersEnteredPassword.equals(UsersStoredPassword)){

on Objects manipulation

== means, pointing to the same address? or, its the exactly same object?

equals compares the content.

Upvotes: 1

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