java.util.concurrent.Callable

標籤：

/** * A task that returns a result and may throw an exception. * Implementors define a single method with no arguments called * {@code call}. * * <p>The {@code Callable} interface is similar to {@link * java.lang.Runnable}, in that both are designed for classes whose * instances are potentially executed by another thread.  A * {@code Runnable}, however, does not return a result and cannot * throw a checked exception. * * <p>The {@link Executors} class contains utility methods to * convert from other common forms to {@code Callable} classes. * * @see Executor * @since 1.5 * @author Doug Lea * @param <V> the result type of method {@code call} */@FunctionalInterfacepublic interface Callable<V> {    /**     * Computes a result, or throws an exception if unable to do so.     *     * @return computed result     * @throws Exception if unable to compute a result     */    V call() throws Exception;
}

Callable 和 Runnable 的使用方法大同小異， 區別在於： 
1.Callable 使用 call（） 方法， Runnable 使用 run() 方法 
2.call() 可以傳回值， 而 run()方法不能返回。 
3.call() 可以拋出受檢查的異常，比如ClassNotFoundException， 而run()不能拋出受檢查的異常。 

java.util.concurrent.Callable