ExecutorService has API's like getPoolSize and getTaskCount There is how I get pool-size task-count inside pipeline-async or equivalent?

You cannot

You should be very careful if you are using pipeline-async, it is very easy to make mistakes with

If I need things like task-count, should I continue with ExecutorService?

If you are using pipeline-async then you pretty much need an executor somewhere

pipeline-async is basically the pipeline machinery but "run the tasks somewhere else", and that somewhere else is usually going to be some kind of work queue kind of thing

An executor, or some kind nio worker thing, or whatever