Chapter 12
The java.lang Package

NullPointerException

Name

Synopsis

Class Name:

java.lang.NullPointerException

Superclass:

java.lang.RuntimeException

Immediate Subclasses:

None

Interfaces Implemented:

None

Availability:

JDK 1.0 or later

A NullPointerException is thrown when there is an attempt to access an object through a null object reference. This can occur when there is an attempt to access an instance variable or call a method through a null object or when there is an attempt to subscript an array with a null object.

Class Summary

public class java.lang.NullPointerException 
             extends java.lang.RuntimeException {
  // Constructors
  public NullPointerException();
  public NullPointerException(String s);
}

Constructors

NullPointerException

public NullPointerException()

Description: This constructor creates a NullPointerException with no associated detail message.

public NullPointerException(String s)

Parameters

s: The detail message.

Description

This constructor creates a NullPointerException with the specified detail message.

Inherited Methods

Method	Inherited From	Method	Inherited From
`clone()`	`Object`	`equals(Object)`	`Object`
`fillInStackTrace()`	`Throwable`	`finalize()`	`Object`
`getClass()`	`Object`	`getLocalizedMessage()`	`Throwable`
`getMessage()`	`Throwable`	`hashCode()`	`Object`
`notify()`	`Object`	`notifyAll()`	`Object`
`printStackTrace()`	`Throwable`	`printStackTrace(PrintStream)`	`Throwable`
`printStackTrace(PrintWriter)`	`Throwable`	`toString()`	`Object`
`wait()`	`Object`	`wait(long)`	`Object`
`wait(long, int)`	`Object`