Why do these strings evaluate to false even when i enter them exactly right?

Question

I am writing a simple program to get to grips with using the Scanner in Java. The program has a stored value for user_1 and asks the user to provide the String variable username which is then checked against user_1 using the == operator, however even when username matches user_1 it still evaluates to false. I'm sure I must be missing something simple, any help would be appreciated. I even added the line printing both variable just to double check they are the same!!

import java.util.Scanner;

public class HelloWorld {

public static void main(String[] args) {

    String user_1 = ("lucasRHCP");

    Scanner input = new Scanner(System.in);
    System.out.println("Enter your username: ");
    String username = input.nextLine();

    System.out.println(user_1 + " " + username);

    if (username == user_1){
        System.out.println("True");
    }
    else {
        System.out.println("False");
    }
}   
}

score 2 · Answer 1 · answered Mar 28 '15 at 23:54

2

NEVER compare objects (and String is am object) with ==, use equals() method

answered Mar 28 '15 at 23:54

Germann Arlington

3,315
2
17
19

To add to your reason for this, it's because `==` compares objects. Primitives like the `int`, `byte`, `long`, `boolean`, `enum` are primitives, and so on. – CoderMusgrove Mar 28 '15 at 23:55
@CoderMusgrove I left that for the OP to discover – Germann Arlington Mar 29 '15 at 09:49

score 2 · Answer 2 · answered Mar 28 '15 at 23:54

With == you compare whether two objects are the same, not whether their value is. You want to compare their values, so you need to use .equals():

if (username.equals(user_1)) {
  System.out.print("True");
} else {
  System.out.print("False");
}

It's like comparing two red identical looking car, they are identical but not the same thing. In java two variables can be both the same thing or two distinct, alike things.

score 0 · Answer 3 · answered Mar 28 '15 at 23:54

0

You can't compare Strings in java using ==

You should use the String class methods

username.equals(user_1);

answered Mar 28 '15 at 23:54

Devid Farinelli

7,514
9
42
73

Why do these strings evaluate to false even when i enter them exactly right?

3 Answers3