ri/src/main/java/javax/annotation/concurrent/Immutable.java

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;

/*
 * 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
 */

/**
 * Immutable
 * 
 * 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 * to other immutable objects, and that methods do not publish references to any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 {
}