Check Boolean if null

Question

Boolean valid = null;
if (valid == null) {
    log.info("******");
}

I have the expression above, I wanted to check if Boolean value is null and if it is then execute statement inside if clause, but what happened is that it throws me a NullPointerException. What should I do to have my if clause evaluated with that given condition valid == null. Thanks in advance

The first thing you should do is ask yourself why you would ever use a `Boolean` object and assign it null. Other than that your code works. Probably `log` is a null-reference you can't call a method on. — Ben, May 28 '18 at 06:16
This code doesn't throw NullPointerException (unless `log` is `null`) — Eran, May 28 '18 at 06:17
As it is, it won't throw a nullpointerexception. That would happen though if you unboxed the boolean, or if you tried `if(valid)` — ernest_k, May 28 '18 at 06:18
thanks everyone. I forgot that before the expression "valid == null" I checked it first if its "!valid", hence I got NPE since first expression evaluates if it contains a value which is false. — Zerosero, May 29 '18 at 00:24

score 0 · Answer 1 · answered May 28 '18 at 06:21

0

For sure, your log object contains null reference. You can't invoke any method with null reference. Try this:

Boolean valid = null;
if(valid == null) {
     System.out.println("Hello");
}

answered May 28 '18 at 06:21

Abhishek

688
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Check Boolean if null

1 Answers1