CompletableFuture::supplyAsync(() -> IO bound queries)
How do I chose an Executor for CompletableFuture::supplyAsync to avoid polluting the ForkJoinPool.commonPool().
There are many options in Executors (newCachedThreadPool, newWorkStealingPool, newFixedThreadPool etc)
And I read about new ForkJoinPool here
How do I chose the right one for my use case ?
You should use public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier, Executor executor) method.
As executor you can use any from the Executors.new.. - it depends on your needs.
It's better to use newFixedThreadPool() rather than newCachedThreadPool(), since newCachedThreadPool() can lead to performance issues creating to many threads or even throw OutOfMemoryError.
Here's a very nice article with good examples.
Adding to Anton's Answer, it is wise to use newFixedThreadPool rather than newCachedThreadPool unless you know the operation will not cause OutOfMemoryError. Since, your request is an i/o process the usage of Async nio request such as AsynchronousFileChannel or Async Rest Client...etc could greatly supplement your performance.
来源：https://stackoverflow.com/questions/33377177/how-to-chose-an-executor-for-completablefuturesupplyasync