NullPointerException : Java Glossary

by Roedy Green ©1996-2008 Canadian Mind Products
Go to : punctuation 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 (all)

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 .

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

	Please email your feedback for publication, errors, omissions, broken/redirected link reports and suggestions to improve this page to Roedy Green :
	Canadian Mind Products
	mindprod.com IP:[65.110.21.43]
	Your face IP:[38.103.63.18]
	You are visitor number 24,577.
	You can get a fresh copy of this page from:	or possibly from your local J: drive (Java virtual drive/Mindprod website mirror)
	http://mindprod.com/jgloss/nullpointerexception.html	J:\mindprod\jgloss\nullpointerexception.html