Module java.base

Package 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 an application attempts to use null in a case where an object is required. These include:

• Calling the instance method of a null object.
• Accessing or modifying the field of a null object.
• Taking the length of null as if it were an array.
• Accessing or modifying the slots of null as if it were an array.
• Throwing null as if it were a Throwable value.

Applications should throw instances of this class to indicate other illegal uses of the null object. NullPointerException objects may be constructed by the virtual machine as if suppression were disabled and/or the stack trace was not writable.

Since:

1.0

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
NullPointerException()	Constructs a NullPointerException with no detail message.
NullPointerException(String s)	Constructs a NullPointerException with the specified detail message.

Method Summary

Modifier and Type	Method	Description
String	getMessage()	Returns the detail message string of this throwable.

Methods declared in class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods declared in class java.lang.Object

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

Constructor Details

NullPointerException

public NullPointerException()

Constructs a NullPointerException with no detail message.

NullPointerException

public NullPointerException(String s)

Constructs a NullPointerException with the specified detail message.

Parameters:

s - the detail message.

Method Details

getMessage

public String getMessage()

Returns the detail message string of this throwable.

If a non-null message was supplied in a constructor it is returned. Otherwise, an implementation specific message or null is returned.

Overrides:

getMessage in class Throwable

Implementation Note:

If no explicit message was passed to the constructor, and as long as certain internal information is available, a verbose description of the null reference is returned. The internal information is not available in deserialized NullPointerExceptions.

Returns:

the detail message string, which may be null.