FindBugs：可能的空指针取消引用

Question

Hi I have the following method:

protected boolean shouldCheckLimit() {
    if (startDate == null || endDate == null) {
        return true;
    }
    final Long currentTime = System.currentTimeMillis();
    if (startDate <= currentTime && currentTime < endDate) {
        return true;
    }
    return false;
}

The problem is that findBugs found the following problem:

Possible null pointer dereference of TimeIntervalLimit.startDate in com.bet.blues.limit.TimeIntervalLimit.shouldCheckLimit() [Scary(8), Normal 

I have to mention that startDate and endDate are Long variables. I tried to add checks for null inside if condition, also I tried to use longValue() method, but with no result. Do you have any idea how can I fix this problem? Could be a bug on fndBugs side?

Answer 1

You get the error because startDate (and also endDate ) might be null . But you checked them for null , so that shouldn't be possible, right?

The answer is that both are global and might be set to null at any time by another thread.