java.util.concurrent.RejectedExecutionException：
java.util.concurrent.RejectedExecutionException：
提问于 2015-03-10 22:19:55
我试着做一些小的poc来理解Futures.addCallback(未来，回调)和Futures.addCallback(未来，回调，executor1)之间的区别。根据我的理解，在后一种情况下，回调应该由函数调用中指定的executor1运行。但是，在运行下面的代码片段时，我无法找出上述异常的原因：
class MyTest implements Callable<Integer>{
int i;
int j;
public MyTest(int k, int l) {
i = k;
j = l;
}
public int getI() {
return i;
}
public void setI(int i) {
this.i = i;
}
public int getJ() {
return j;
}
public void setJ(int j) {
this.j = j;
}
@Override
public Integer call() throws Exception {
System.out.println(Thread.currentThread().getName());
System.out.println("Computing.........");
Thread.currentThread().sleep(5000);
return i + j;
}
}
Callable<Integer> call = new MyTest(1,2);
ListeningExecutorService executor = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(1));
ListeningExecutorService executor1 = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(1));
//ExecutorService executor = Executors.newFixedThreadPool(1);
ListenableFuture<Integer> future = executor.submit(call);
FutureCallback<Integer> callback = new FutureCallback<Integer>() {
@Override
public void onSuccess(Integer result) {
System.out.println(Thread.currentThread().getName());
System.out.println("Completed Successfully and result is :" + result);
}
@Override
public void onFailure(Throwable t) {
System.out.println("Failed");
}
};
Futures.addCallback(future, callback, executor1);
executor.shutdown();
executor1.shutdown();异常日志
????? ??, ???? ?:??:?? ??????? com.google.common.util.concurrent.ExecutionList executeListener
SEVERE: RuntimeException while executing runnable com.google.common.util.concurrent.Futures$5@37e5f7d7 with executor com.google.common.util.concurrent.MoreExecutors$ListeningDecorator@3d1d9ca7
java.util.concurrent.RejectedExecutionException: Task com.google.common.util.concurrent.Futures$5@37e5f7d7 rejected from java.util.concurrent.ThreadPoolExecutor@39220f5b[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2047)
at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823)
at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369)
at com.google.common.util.concurrent.MoreExecutors$ListeningDecorator.execute(MoreExecutors.java:484)
at com.google.common.util.concurrent.ExecutionList.executeListener(ExecutionList.java:156)
at com.google.common.util.concurrent.ExecutionList.execute(ExecutionList.java:145)
at com.google.common.util.concurrent.ListenableFutureTask.done(ListenableFutureTask.java:91)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:384)
at java.util.concurrent.FutureTask.set(FutureTask.java:233)
at java.util.concurrent.FutureTask.run(FutureTask.java:274)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)回答 1
Stack Overflow用户
发布于 2015-03-11 21:33:10
异常被抛出，因为在您的代码片段中，通过调用executor1.shutdown();来停止executor1，尝试注释掉此行，然后异常就消失了。
如果要在callback完成后关闭executor，请在回调代码中执行shutdown
FutureCallback<Integer> callback = new FutureCallback<Integer>() {
@Override
public void onSuccess(Integer result) {
System.out.println(Thread.currentThread().getName());
System.out.println("Completed Successfully and result is :" + result);
executor1.shutdown(); // shutdown it here!
}
@Override
public void onFailure(Throwable t) {
System.out.println("Failed");
executor1.shutdown(); // shutdown it here!
}
};
Futures.addCallback(future, callback, executor1);
executor.shutdown();
// executor1.shutdown(); // do not stop it here!页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/28966175
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