Is Eclipse's null check analysis confused by JUnit's 'fail'?

Question

I have the following code:

Object foo = someMethod();
if (foo == null) 
    org.junit.Assert.fail("OMG what a horrible error!");
foo.doSomeStuff();

But Eclipse (Neon, M4.6) seems to be unable to detect that that org.junit.Assert.fail method will terminate execution flow, and complains that the last line contains a possible NPE, which it doesn't.

Is that a bug or am I using it wrong ?

Answer 1

Eclipse has a built in list of a few methods which it knows will not return. This includes the JUnit assertNotNull but does not include fail .

Eclise bug 382069 describes this support.

Answer 2

How is Eclipse supposed to know that? As far as it's concerned this is just another library call.

If you use it like this it should work without a NullPointerException:

Object foo = someMethod();
if (foo == null) {
   org.junit.Assert.fail("Jesus Christ what a horrible error!");
} else {
   foo.doSomeStuff();
}

Answer 3

Well, if Assert.fail() would not throw an exception, you would have an NPE. But why would Eclipse / Java know that.

Btw, it's better to use assertNotNull, so you won't have that problem anyway...