"system-dependent default" 线程池是什么?

What is the "system-dependent default" thread pool?

来自AsynchronousFileChannel API:

When an AsynchronousFileChannel is created without specifying a thread pool then the channel is associated with a system-dependent default thread pool that may be shared with other channels.

我没有在其他地方看到过这个术语,也没有通过网络搜索找到任何具体的解释。系统相关的默认线程池到底是什么?它有什么特点?它们在系统之间有何不同?

多读一点文档:

The default thread pool is configured by the system properties defined by the AsynchronousChannelGroup class.

如果你跳 there,你会看到:

In addition to groups created explicitly, the Java virtual machine maintains a system-wide default group that is constructed automatically. Asynchronous channels that do not specify a group at construction time are bound to the default group. The default group has an associated thread pool that creates new threads as needed. The default group may be configured by means of system properties defined in the table below. Where the ThreadFactory for the default group is not configured then the pooled threads of the default group are daemon threads.

...后跟配置参数列表。