TIOBE - Java Coding Standard

Rule: Basic28

Synopsis:	Method call on object which may be null
Language:	Java
Severity Level:	1
Category:	Basic

Description:

The null check is broken since it will throw a Nullpointer itself. The reason is that a method is called on the object when it is null. It is likely that you used || instead of && or vice versa.

class Foo {
 String munge(String string) {
  // should be &&
  if (string!=null || !string.equals(""))
    return string;
  // should be ||
  if (string==null && string.equals(""))
    return string;
 }
}