Base class for Executors and related classes that rely on thread factories.
Generally intended to be used as a mixin-style abstract class, but
can also be used stand-alone.
Set the factory for creating new threads.
By default, new threads are created without any special priority,
threadgroup, or status parameters.
You can use a different factory
to change the kind of Thread class used or its construction
parameters.
Parameters: factory - the factory to use the previous factory