immutable.java

A static analysis tool to find bugs in Java programs

package net.jcip.annotations;
import java.lang.annotation.*;

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 * to other immutable objects, and that methods do not publish references to any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