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java.lang
Class NullPointerException

java.lang.Object
  extended by java.lang.Throwable
      extended by java.lang.Exception
          extended by java.lang.RuntimeException
              extended by 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.

Since:
JDK1.0
See Also:
Serialized Form

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