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From: Jeff Higgins <jeff@invalid.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: ExecutorService.shutdown ambiguity
Date: Fri, 18 Mar 2016 20:52:38 -0000 (UTC)
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On Fri, 18 Mar 2016 12:37:13 -0700, Roedy Green wrote:

> Here is the JavaDoc for ExecutorService.shutdown.
> To me it is ambiguous. How do you read it?
> 
> What happens to a task in queue? 

"... previously submitted tasks are executed ..."

> What happens to a task that is executing?

Presumably it continues executing.
However ExecutorService.shutdown() returns without awaiting completion.
 
> 
>      * Initiates an orderly shutdown in which previously submitted *
>      tasks are executed, but no new tasks will be accepted.
>      * Invocation has no additional effect if already shut down.
>      *
>      * <p>This method does not wait for previously submitted tasks to *
>      complete execution.  Use {@link #awaitTermination
> awaitTermination}
>      * to do that.
>      *
>      * @throws SecurityException if a security manager exists and *     
>         shutting down this ExecutorService may manipulate *        
>      threads that the caller is not permitted to modify *        
>      because it does not hold {@link *        
>      java.lang.RuntimePermission}{@code ("modifyThread")}, *         or
>      the security manager's {@code checkAccess} method *         denies
>      access.
>      */
>     void shutdown();