Question

Is there any way to force the compiler (annotation or othewise) to realize a java function is never returning (i.e. always throwing), so that subsequently it will not error out its usages as the last statement in other functions returning non void?

Here’s a simplified/made-up example:

int add( int x, int y ) {
    throwNotImplemented();  // compiler error here: no return value.
}

// How can I annotate (or change) this function, so compiling add will not yield
// an error since this function always throws?
void throwNotImplemented() {
    ... some stuff here (generally logging, sometimes recovery, etc)
    throw new NotImplementedException();
}

Thank you.

Answer 1

No, it’s not possible.

Note, however, that you can easily work it around as follows:

int add( int x, int y ) {
    throw notImplemented();
}

Exception notImplemented() {
    ... some stuff here (generally logging, sometimes recovery, etc)
    return new NotImplementedException();
}