Scala : Error handling: catching NullPointerException

Catch exceptions of NullPointerException type is usually considered to be a bad practice.

Catch NullPointerException usually occurs in one of three cases:

1. There was a null pointer dereference. The developer decided that it is easier to catch an exception than to solve the problem that caused it.
2. Application deliberately throws NullPointerException to report an error.
3. NullPointerException catcher is part of the mechanism of testing, in which the application is given incorrect data as an input.

Catching NullPointerException is acceptable only in the latter case.