Use of NullPointerException Catch to Detect NULL Pointer Dereference

Catching NullPointerException should not be used as an alternative to programmatic checks to prevent dereferencing a null pointer. Programmers typically catch NullPointerException under three circumstances:

• The program contains a null pointer dereference. Catching the resulting exception was easier than fixing the underlying problem.
• The program explicitly throws a NullPointerException to signal an error condition.
• The code is part of a test harness that supplies unexpected input to the classes under test.

Of these three circumstances, only the last is acceptable.

The weakness is introduced during Implementation stage.