Java Glossary : NullPointerException

Java definitions: 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

You are here : home : Java Glossary : N words : NullPointerException.

NullPointerException

If you try to execute a piece of code like this when s is null you will get a NullPointerException.

s.someMethod();

Java has no pointers; this properly should have been called a NullReferenceException, but it stuck from the early days where C terminology held an unwholesome influence.

It is one of many possible run time errors you can recover from. For hints on how to track down its cause, and the causes of many other errors see the essay on error messages 2004-07-02.

To learn about exceptions in general and try/catch to recover from them, see exceptions.

home	Canadian Mind Products
	mindprod.com IP:[24.87.56.253]
	Your IP:[80.134.30.163]
	You are visitor number 1494.
	Please send errors, omissions and suggestions
	to improve this page to Roedy Green.
	You can get a fresh copy of this page from:	or possibly from your local J: drive mirror:
	http://mindprod.com/jgloss/nullpointerexception.html	J:\mindprod\jgloss\nullpointerexception.html