Question

Is there a sense to handle null pointer exception by such way like

private void doWork(Object object) {
    if (object == null) {
        try {
            throw new IllegalArgumentException();
        } catch (Exception e) {
            e.printStackTrace();
        }
    } else {
        ...
    }
}

Answer 1

First, that code could be written more simply as:

private void doWork(Object object) {
    if (object == null) {
        new IllegalArgumentException().printStackTrace();
    } else {

    }
}

or (almost equivalently) as

private void doWork(Object object) {
    if (object == null) {
        Thread.dumpStack();
    } else {

    }
}

Second, is it doing something useful? Yes, it is printing is a stack trace for the current thread.

Third, is it a good idea? IMO, definitely NOT.

• It is sending stuff to the standard error, which may be going to the console (where it could be lost if nobody is watching) or to /dev/null. Errors should be logged properly using your preferred logging subsystem.

• It looks like it is squashing a probable error condition (i.e. the program is broken because this method has been called with an illegal argument) and then continuing. If this is really an error condition, then the code should probably be bailing out. If it is not, then the stack trace is noise.

---

In short, this looks like a “bandaid” solution to some problem. The correct solution is to remove this code (or replace it with code that simply throws IllegalArgumentException), and when the exception occurs figure out where it is coming from and fix the root problem.