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 use
null in a case where an object is required. These include:- Calling the instance method of a
nullobject. - Accessing or modifying the field of a
nullobject. - Taking the length of
nullas if it were an array. - Accessing or modifying the slots of
nullas if it were an array. - Throwing
nullas if it were aThrowablevalue.
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 aNullPointerExceptionwith no detail message.NullPointerException(String s)Constructs aNullPointerExceptionwith the specified detail message.Method Summary
Methods declared in class java.lang.Throwable
addSuppressed,fillInStackTrace,getCause,getLocalizedMessage,getMessage,getStackTrace,getSuppressed,initCause,printStackTrace,printStackTrace,printStackTrace,setStackTrace,toString
Constructor Details
NullPointerException
public NullPointerException()Constructs aNullPointerExceptionwith no detail message.NullPointerException
Constructs aNullPointerExceptionwith the specified detail message.- Parameters:
s- the detail message.