Question

I’m reading about Channels in the JDK 7 docs (here), and stumbled upon this:

Multiplexed, non-blocking I/O, which is much more scalable than thread-oriented, blocking I/O, […]

Is there a simple explanation as to why this is so?

Answer 1

“Blocking” means that threads have to wait as long as necessary for a resource to become available…which means, by definition, threads will be sitting around waiting for resources. Non-blocking avoids this sort of thing.

Generally, non-blocking solutions are trickier, but they avoid resource contention, which makes it much easier to scale up. (That said, the point of Channel is to make this less tricky.)