java.lang

Class NullPointerException

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

java.lang.NullPointerException

All Implemented Interfaces:

Serializable

public class NullPointerException
extends RuntimeException

Thrown when attempting to use null where an object is required. The Virtual Machine automatically throws this exception for the following:

• Calling an instance method on a null object
• Accessing or modifying a field of a null object
• Taking the array length of a null array
• Accessing or modifying the slots of a null array
• Throwing a null Throwable
• Synchronizing on a null object

Applications should also throw NullPointerExceptions whenever null is an inappropriate parameter to a method.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
NullPointerException() Create an exception without a message.
NullPointerException(String s) Create an exception with a message.

Method Summary

Methods inherited from class java.lang.Throwable

fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

NullPointerException

public NullPointerException()

Create an exception without a message.

NullPointerException

public NullPointerException(String s)

Create an exception with a message.

Parameters:

s - the message