Ruby将字符串（$ 100.99）转换为float或BigDecimal(Ruby convert string ($100.99) to float or BigDecimal)

 使用单独的线程池是很好的默认实践，并且共享线程池是一种（可能是过早的）优化。 
 
 通过Java 7，答案是否定的，没有默认线程池，并且建议有许多线程池。 这是一种很好的分离方式，可以防止一组任务中的阻塞行为干扰另一组任务。 
 
 如果你分享线程池，你应该问问题如下： 
 
 
 
 日志框架能够区分任务吗？ （线程是区分的一种方式。） 
 
 
 如果任务池A意外地请求过多的线程中断，应该任务池B是否饿死？ 当您注意到任务池B失败时，您是否能够诊断任务池A中的问题？ 
 
 
 如果A池阻止B饿死？ 
 
 
 也许你创建了一个像LightweightThreadpool一样的东西。 你写的前5个任务以轻量级的方式使用它。 而第六项任务......的确如此，除了它还将错误写入磁盘，并且这些错误出人意料地大，有时还有很多错误，并且它们不会受到限制。 突然之间，前5项任务被迫挨饿，不知道是什么打击了他们，而且，当你写这些任务时，你确信他们是安全的，可能没有为这类事件做好准备。 
 
 所以共享线程池就好了，因为在同一台服务器上运行两个不同的进程是可以的。 您应该首先仔细考虑资源管理，并明白现在这些任务是资源耦合的。 缺少默认线程池会试图强制默认使用单独的线程池，并在共享之前仔细考虑这些问题。 
 
 从Java 8开始，答案是“是”（根据Tagir对此问题的回答 ）。 但是你会注意到，如果你向该线程池提交阻塞任务，一切都将开始可怕的失败。 

Using separate threadpools is good, default practice, and sharing threadpools is a (possibly premature) optimization.
 
Through Java 7 the answer is no, there is not a default threadpool, and the recommendation is to have many threadpools. It's good separation and will prevent blocking behavior on one collection of tasks from interfering with another.
 
If you share threadpools you should ask questions like:
 
 
 
will the logging framework be able to distinguish tasks? (Threads is one way to distinguish.)
 
 
If task pool A accidentally requests way too many threads and gets cut off, should task pool B starve? When you notice task pool B is failing will you be able to diagnose the problem in task pool A?
 
 
If pool A blocks should B starve?
 
 
Maybe you create something like a LightweightThreadpool. And the first 5 tasks you write use it in a lightweight fashion. And the 6th task... does, except it also writes errors to disk, and those errors are surprisingly big, and sometimes there's many of them, and they're not throttled. Suddenly the first 5 tasks are starved and have no idea what hit them, and furthermore, when you wrote those tasks, you really believed they were secure and might not have prepared for this type of incident.
 
So sharing threadpools is about as okay as having two different processes run on the same server is okay. You should think about resource management very carefully first and understand that the tasks are resource-coupled now. The lack of a default threadpool is trying to force you to use separate ones by default, and think about these questions carefully before sharing one.
 
As of Java 8 the answer is "yes" (per Tagir's answer on this question). But you will notice everything will start horribly failing if you submit blocking tasks to that threadpool.