下面的例子SimpleThreads中用到了2-5节中的几个方法和概念。
SimpleThreads中有两个线程，一个是所有Java程序都有的主线程main，另一个就是在主线程中创建的runnble对象——循环输出消息的线程t，t在主线程中调用了join方法，因此主线程需等待线程t的完成。但如果t线程运行时间过长（本例中用patience加以控制），主线程就会中断。
在本例中有许多输出语句， 用以反映线程运行状态及线程对interrupt异常的反应。
public class SimpleThreads {
// Display a message, preceded by
// the name of the current thread
static void threadMessage(String message) {
String threadName =
Thread.currentThread().getName();
System.out.format("%s: %s%n",
threadName,
message);
}
private static class MessageLoop
implements Runnable {
public void run() {
String importantInfo[] = {
"Mares eat oats",
"Does eat oats",
"Little lambs eat ivy",
"A kid will eat ivy too"
};
try {
for (int i = 0;
i < importantInfo.length;
i++) {
// Pause for 4 seconds
Thread.sleep(4000);
// Print a message
threadMessage(importantInfo[i]);
}
} catch (InterruptedException e) {
threadMessage("I wasn't done!");
}
}
}
public static void main(String args[])
throws InterruptedException {
// Delay, in milliseconds before
// we interrupt MessageLoop
// thread (default one hour).
long patience = 1000 * 60 * 60;
// If command line argument
// present, gives patience
// in seconds.
if (args.length > 0) {
try {
patience = Long.parseLong(args[0]) * 1000;
} catch (NumberFormatException e) {
System.err.println("Argument must be an integer.");
System.exit(1);
}
}
threadMessage("Starting MessageLoop thread");
long startTime = System.currentTimeMillis();
Thread t = new Thread(new MessageLoop());
t.start();
threadMessage("Waiting for MessageLoop thread to finish");
// loop until MessageLoop
// thread exits
while (t.isAlive()) {
threadMessage("Still waiting...");
// Wait maximum of 1 second
// for MessageLoop thread
// to finish.
t.join(1000);
if (((System.currentTimeMillis() - startTime) > patience)
&& t.isAlive()) {
threadMessage("Tired of waiting!");
t.interrupt();
// Shouldn't be long now
// -- wait indefinitely
t.join();
}
}
threadMessage("Finally!");
}
} 运行结果：
main: Starting MessageLoop thread main: Waiting for MessageLoop thread to finish main: Still waiting... main: Still waiting... main: Still waiting... main: Still waiting... main: Still waiting... Thread-0: Mares eat oats main: Still waiting... main: Still waiting... main: Still waiting... main: Still waiting... Thread-0: Does eat oats main: Still waiting... main: Still waiting... main: Still waiting... main: Still waiting... Thread-0: Little lambs eat ivy main: Still waiting... main: Still waiting... main: Still waiting... main: Still waiting... Thread-0: A kid will eat ivy too main: Finally!
偷偷把patience改掉之后呢：
long patience = 1000 * 60 * 60;改为 long patience = 1000;
运行效果是这样的：
main: Starting MessageLoop thread main: Waiting for MessageLoop thread to finish main: Still waiting... main: Tired of waiting! Thread-0: I wasn't done! main: Finally!原文：
http://docs.oracle.com/javase/tutorial/essential/concurrency/simple.html