java.lang.NullPointerException (JDK 1.0)

Signals an attempt to access a field or invoke a method of a null object.

public class NullPointerException extends RuntimeException {
 // Public Constructors public NullPointerException();
public NullPointerException(String s);
}

Hierarchy:

Object->Throwable(Serializable)->Exception->RuntimeException->NullPointerException