How to stop the rest of code in current method from executing in Java?

Question

I have 4 textboxes, 2 of them being password boxes (for the user to confirm their password).

Here's my code:

public void actionPerformed(ActionEvent arg0) {
    String username = usernameField.getText();
    String emailAddress = emailField.getText();
    String password1 = passwordField1.getText();
    String password2 = passwordField2.getText();
    if (password1 != password2) {
        [code here]
    }
}

How can I make it so that if the passwords aren't equal it stops the rest of the code in that method from executing?

@Makoto He didn't ask anything about how to compare strings. He asked how to stop further code execution of the method if a certain condition was met. — jheimbouch, Feb 05 '16 at 20:12
"The rest of the method" refers to the block of the `if` statement. Pretty sure it was correctly closed. — Chris Martin, Feb 05 '16 at 20:22
@ChrisMartin: I'm comfortable with a reopen on this one since it's not a carte-blanche duplicate. Yes, the duplicate is related, but it's not asking the exact same question with a slightly different flavor. — Makoto, Feb 05 '16 at 20:24

score 3 · Accepted Answer · edited May 23 '17 at 11:59

3

There is a significant problem before you can do this: you have to compare strings correctly. Then, you can decide what to do if they're false. Ultimately, using return in a void method is acceptable if you only want to return.

if (!password1.equals(password2)) {
    // [code here]
}

However, the better approach would be to do a simple blanket check, and avoid the early return - if the passwords are valid, then do operations in the scope of that block. The fall-through case would exit the method early.

public void actionPerformed(ActionEvent arg0) {
    String username = usernameField.getText();
    String emailAddress = emailField.getText();
    String password1 = passwordField1.getText();
    String password2 = passwordField2.getText();
    if (password1.equals(password2)) {
        // code on success here
    }
}

edited May 23 '17 at 11:59

Community

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answered Feb 05 '16 at 20:15

Makoto

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Thanks :) I was able to figure it out. Sorry for posting this "duplicate" or whatnot, it seems I had more than 1 issue. EDIT: Regarding the way you suggested doing it, I'd have to include a bunch of nested if statements due to the fact that I also want to check username length, password length, etc... – Justin G Feb 05 '16 at 20:17
@JustinG: I admit I acted a bit in haste when closing it, but generally when one sees two strings being compared with `==`, it's understandable. Glad you got it figured out. – Makoto Feb 05 '16 at 20:18

score 2 · Answer 2 · answered Feb 05 '16 at 20:16

2

Never compare strings with boolean operators - Bad practice!

To solve your question just do this:

if (!password1.equals(password2)) {
    return; 
}

answered Feb 05 '16 at 20:16

Maciej Cygan

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user3437460 · Answer 3 · 2016-02-05T20:44:45.800

How to stop the rest of code in current method from executing in Java?

I would say there are 2 ways:

Let the program flow naturally to the end of the method:

public void actionPerformed(ActionEvent e){
    if(password1.equals(password2)){
        //Do all the things if password is correct
    }            
} //<-- If password is incorrect, point of execution will come to here

To exit a method before you reach the end of the method, you can use return:

public void actionPerformed(ActionEvent e){
    if(!password1.equals(password2)){
        return;
    }
    else{
        //Do all the things if password is correct
    }
}

score 1 · Answer 4 · edited Feb 05 '16 at 20:18

1

You can add the return statement:

return;

edited Feb 05 '16 at 20:18

Makoto

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answered Feb 05 '16 at 20:09

jheimbouch

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Does this fix the comparison? – Makoto Feb 05 '16 at 20:11
And this is why there's a downvote: you failed to address the actual problem. Yes, returning is correct, but it's not going to work out for them if *all* they do is this. – Makoto Feb 05 '16 at 20:13
@cricket_007: your edit leaves a bad taste in my mouth, since it's not the answer that was originally given. – Makoto Feb 05 '16 at 20:17
@Makoto, can we chat? – jheimbouch Feb 05 '16 at 20:21
I don't have the luxury of time right now; I've just taken a brief break, but if you put a question in a chatroom that I can get to, I will answer it when I have a spare moment. – Makoto Feb 05 '16 at 20:23

How to stop the rest of code in current method from executing in Java?

4 Answers4