Hello,
Yes, you need to keep the conenctions open and reuse them for each request.
I am guessing that you are creating a JPPFClient instance for each request, is this correct?
If yes, then you will need to change your design a little bit and ensure that all requests use the same instance, which you can implement as a singleton or any other pattern that allows you to use always this instance.
I hope this clarifies.
Sincerely,
-Laurent