javax.annotation.concurrent.Immutable Maven / Gradle / Ivy
/*
* Copyright (c) 2005 Brian Goetz
* Released under the Creative Commons Attribution License
* (http://creativecommons.org/licenses/by/2.5)
* Official home: http://www.jcip.net
*/
package javax.annotation.concurrent;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* The class to which this annotation is applied is immutable. This means that
* its state cannot be seen to change by callers. Of necessity this means that
* all public fields are final, and that all public final reference fields refer
* to other immutable objects, and that methods do not publish references to any
* internal state which is mutable by implementation even if not by design.
* Immutable objects may still have internal mutable state for purposes of
* performance optimization; some state variables may be lazily computed, so
* long as they are computed from immutable state and that callers cannot tell
* the difference.
*
* Immutable objects are inherently thread-safe; they may be passed between
* threads or published without synchronization.
*/
@Documented
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.CLASS)
public @interface Immutable {
}