checked exceptions详解

Thread. sleep()是否会抛出checked exception?

下面为Thead类sleep()的方法的源码

/** * Causes the currently executing thread to sleep (temporarily cease * execution) for the specified number of milliseconds, subject to * the precision and accuracy of system timers and schedulers. The thread * does not lose ownership of any monitors. * * @param millis * the length of time to sleep in milliseconds * * @throws IllegalArgumentException * if the value of {@code millis} is negative * * @throws InterruptedException * if any thread has interrupted the current thread. The * <i>interrupted status</i> of the current thread is * cleared when this exception is thrown. */
public static native void sleep(long millis) throws InterruptedException;

可以看到sleep()方法会抛出InterruptedException，而根据checked exception的定义，所有Exception的子类，只要不是RuntimeException都是checked exception。

下面是InterruptedException的源码：

package java.lang;
/**
* Thrown when a thread is waiting, sleeping, or otherwise occupied,
* and the thread is interrupted, either before or during the activity.
* Occasionally a method may wish to test whether the current
* thread has been interrupted, and if so, to immediately throw
* this exception.
The following code can be used to achieve
* this effect:
* <pre>
*
if (Thread.interrupted())
// Clears interrupted status!
*
throw new InterruptedException();
* </pre>
*
* @author
Frank Yellin
* @see
java.lang.Object#wait()
* @see
java.lang.Object#wait(long)
* @see
java.lang.Object#wait(long, int)
* @see
java.lang.Thread#sleep(long)
* @see
java.lang.Thread#interrupt()
* @see
java.lang.Thread#interrupted()
* @since
JDK1.0
*/
public
class InterruptedException extends Exception {
private static final long serialVersionUID = 6700697376100628473L;
/**
* Constructs an <code>InterruptedException</code> with no detail
message.
*/
public InterruptedException() {
super();
}
/**
* Constructs an <code>InterruptedException</code> with the
* specified detail message.
*
* @param
s
the detail message.
*/
public InterruptedException(String s) {
super(s);
}
}

可见InterruptedException会抛出checked exception