Utility method to convert Boolean into boolean and handle null in Java

Question

Is there a utility method in Java which converts Boolean into boolean and automatically handles null reference to Boolean as false?

possible duplicate of [Booleans, conditional operators and autoboxing](http://stackoverflow.com/questions/3882095/booleans-conditional-operators-and-autoboxing) — DavidPostill, Jul 25 '14 at 07:41
@StephenC Yeah ..but OP might searching for a smart line of code ;) (look at skeets solution) — Suresh Atta, Jul 25 '14 at 07:53

score 100 · Accepted Answer · answered Jul 25 '14 at 07:40

100

How about:

boolean x = Boolean.TRUE.equals(value);

? That's a single expression, which will only evaluate to true if value is non-null and a true-representing Boolean reference.

answered Jul 25 '14 at 07:40

Jon Skeet

Shailesh Aswal · Answer 2 · 2014-07-25T15:01:31.263

9

On java 8 you can do:

static boolean getPrimitive(Boolean value) {
        return Optional.ofNullable(value).orElse(false);
}

You can also do:

static boolean getPrimitive(Boolean value) {
        return Boolean.parseBoolean("" + value);
}

edited Jul 25 '14 at 15:01

answered Jul 25 '14 at 09:10

Shailesh Aswal

2

These both allocate an unnecessary object. [Jon Skeet's answer](https://stackoverflow.com/a/24950467) doesn't. – Clement Cherlin Mar 24 '21 at 11:51
both are 'valid' and memory overheads are negligible.(The first one is simply an optional return, if its really so bad?) I am very well aware of 'jon skeets' answer, but this is more to demonstrate what is possible, (more so with OP's context of automatically handling null reference for Boolean). – Shailesh Aswal Aug 06 '21 at 06:26
1

One unnecessary object allocation per call is not negligible in code that is called, in a practical use case, once per boolean column, per row, per database fetch. Yes, the JVM *might* be able to optimize away the Optional via escape analysis. But it also *might* not. Why use a longer, less clear, allocating idiom when a shorter, clearer, non-allocating alternative exists? – Clement Cherlin Aug 10 '21 at 14:43
with all due respect, please refer the OP, it didnt ask for most optimum way to do it, but the way in which null is handled automatically. Please take things in context. By your reasoning I suppose you are advocating not to use Optional? PS: The accepted answer is the best fit. – Shailesh Aswal Aug 11 '21 at 04:26
1

I have no problem with Optional when used as intended, a return type for methods which may or may not return a result. – Clement Cherlin Aug 11 '21 at 13:29

score 2 · Answer 3 · edited Mar 24 '21 at 21:43

2

I don't know whether it exists or not. I'd write a one liner like:

public static boolean getPrimitiveBoolean(Boolean bool) {    
   return bool == null ? false : bool.booleanValue();
}

edited Mar 24 '21 at 21:43

Clement Cherlin

answered Jul 25 '14 at 07:40

Suresh Atta

score 2 · Answer 4 · answered Jul 25 '14 at 07:41

2

Are you looking for a ready-made utility ? Then I think Commons-Lang BooleanUtils is the answer. It has a method toBoolean(Boolean bool).

answered Jul 25 '14 at 07:41

AllTooSir

Clement Cherlin · Answer 5 · 2021-03-24T12:45:40.047

1

If you're golfing, an explicit null check followed by automatic unboxing is shorter than the canonical answer.

boolean b=o!=null&&o; // For golfing purposes only, don't use in production code

edited Mar 24 '21 at 12:45

answered Mar 24 '21 at 12:22

Clement Cherlin

Connorelsea · Answer 6 · 2014-07-25T08:37:52.617

0

This would be a method you could write that would do the trick. This would return false if the Boolean is null.

public static boolean toBooleanDefaultIfNull(Boolean bool) {
    if (bool == null) return false;
    return bool.booleanValue();
}

edited Jul 25 '14 at 08:37

answered Jul 25 '14 at 07:40

Connorelsea

1

The return bool.booleanValue() ? true : false; is pretty useless, just do return bool.booleanValue() ;) – flotothemoon Jul 25 '14 at 08:32
1

Skeet's answer is much better than this, but I'll change mine with your suggestion anyways. – Connorelsea Jul 25 '14 at 08:38

6 Answers6