How to avoid null checking in Java?

Question

I use object != null a lot to avoid NullPointerException.

Is there a good alternative to this?

For example I often use:

Answer 1

1. Never initialise variables to null.
2. If (1) is not possible, initialise all collections and arrays to empty collections/arrays.

Doing this in your own code and you can avoid != null checks.

Most of the time null checks seem to guard loops over collections or arrays, so just initialise them empty, you won't need any null checks.

// Bad
ArrayList lemmings;
String[] names;

void checkLemmings() {
    if (lemmings != null) for(lemming: lemmings) {
        // do something
    }
}



// Good
ArrayList lemmings = new ArrayList();
String[] names = {};

void checkLemmings() {
    for(lemming: lemmings) {
        // do something
    }
}

There is a tiny overhead in this, but it's worth it for cleaner code and less NullPointerExceptions.