Catch NullPointerException

NVD Categorization

CWE-395: 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.

Description

It is generally a bad practice to catch NullPointerException.

Programmers typically catch NullPointerException under three circumstances:

  1. The program contains a null pointer dereference. Catching the resulting exception was easier than fixing the underlying problem.
  2. The program explicitly throws a NullPointerException to signal an error condition.
  3. 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.

Risk Factors

TBD

Examples

The following code mistakenly catches a NullPointerException.

try {
  mysteryMethod();
} catch (NullPointerException npe) {
  ...
}

References

Note: A reference to related CWE or CAPEC article should be added when exists. Eg:

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