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:

  • 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.