if->return vs. if->else efficiency

Question

This may sound like a silly question, and I hesitated to post it, but still: if something needs to run only in a certain condition, which of these is more efficient:

Answer 1

It's a style thing. The performance is not relevant; both produce nearly identical machine code.

A few considerations on the style:

If you want to avoid 'horizontal programming', you might want to prefer B to avoid nested conditions. For example, if you want to add exceptions without affecting the flow of the method too much:

A:

public String getDescription(MyObject obj) {
    if (obj == null) {
        return "";
    } else {
        if (!obj.isValid()) {
            return "invalid";
        } else {
            ...
        }
    }
 }

B:

public String getDescription(MyObject obj) {
    if (obj == null) {
        return "";
    }

    if (!obj.isValid()) {
        return "invalid";
    }

    ....
 }

But the difference is minimal if you ask me. Definitely not worth a 'code style war'.