What is the best practice for using the NOT operator in IF conditions in Java?

General Discussions
1

I’ve heard that avoiding the NOT operator (!) in IF conditions can improve code readability.

For example, writing if (doSomething()) is considered better than if (!doSomething()).

How true is this in practice?

Should we always avoid using NOT in Java when writing IF conditions, or are there cases where it’s actually better to use it?

2

You’re absolutely right that avoiding ! in Java can improve readability.

Instead of writing:

if (!isUserNotActive()) {
    sendNotification();
}

Try rewriting the method or condition to use positive logic, like this:

if (isUserActive()) {
    sendNotification();
}

This makes it easier to understand at a glance—“if the user is active, send a notification” is much clearer than “if the user is NOT inactive”.

3

If you must use ! in Java, another way to improve readability is by storing conditions in well-named variables. Instead of this:

if (!data.isEmpty() && !isProcessing) {
    processData();
}
Use:
boolean hasData = !data.isEmpty();
boolean isReady = !isProcessing;

if (hasData && isReady) {
    processData();
}

This keeps your IF condition clean and readable.

4

Sometimes using NOT in Java can lead to complex, hard-to-read nested conditions. Instead of:

if (!user.isBlocked()) {
    if (!user.isInactive()) {
        sendWelcomeMessage();
    }
}
Use early returns:

if (user.isBlocked()) {
    return;
}
if (user.isInactive()) {
    return;
}
sendWelcomeMessage();Copy code

This way, the main logic is not buried inside multiple conditions, making the code more intuitive.