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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 classNullPointerExceptionextendsRuntimeException

Thrown when an application attempts to usenull in a case where an object is required. These include:

Calling the instance method of anull object.
Accessing or modifying the field of anull object.
Taking the length ofnull as if it were an array.
Accessing or modifying the slots ofnull as if it were an array.
Throwingnull as if it were aThrowable value.

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

Since:

1.0

See Also:

Serialized Form

Constructor Summary
Constructors
Constructor
Description
NullPointerException()
Constructs aNullPointerException with no detail message.
NullPointerException(String s)
Constructs aNullPointerException 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 aNullPointerException with no detail message.
- NullPointerException
  public NullPointerException(String s)
  Constructs aNullPointerException 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 ornull 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 benull.

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