volatile : Java Glossary

by Roedy Green ©1996-2009 Canadian Mind Products
index page for letter ⇒ 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)

volatile: The volatile keyword is used on variables that may be modified simultaneously by other threads. This warns the compiler to fetch them fresh each time, rather than caching them in registers. This also inhibits certain optimisations that assume no other thread will change the values unexpectedly. Since other threads cannot see local variables, there is never any need to mark local variables volatile. You need synchronized to co-ordinate changes to variables from different threads, but often volatile will do just to look at them. volatile does not guarantee you atomic access, e.g. a ++;
synchronized
thread
thread safe code
transient

	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:[38.103.63.58]
	You are visitor number 238,829.
	You can get a fresh copy of this page from:	or possibly from your local J: drive (Java virtual drive/mindprod.com website mirror)
	http://mindprod.com/jgloss/volatile.html	J:\mindprod\jgloss\volatile.html