Sometimes you can guarantee that a particular variable will never be null. For example when that variable has just been assigned a newly created object or is the exception caught by a catch clause. A null check on such a variable is misleading, and can potentially indicate a logic error.

Do not check a variable for null if a null value is clearly impossible.

The following example shows a null check on a newly created object. An object returned by new can never be null, so this check is superfluous.

Java Language Specification: Creation of New Class Instances, Execution of try-catch.