This answer is no. With a single node, you can only execute one job at a time. It ensues that if you want to execute multiple jobs concurrently on a JPPF grid, you will need multiple nodes.
However, it doesn't mean that if you submit multiple jobs, each job will wait until the previous job is completed to start. The JPPF server attempts to be fair when jobs have the same priority.
For example, let's say you have jobA and jobB, each with 50 tasks and the same priority, and you use the "manual" load-balancing algorithm with a size of 10 (the server will send 10 tasks at a time to each node). If you only have one node, the execution flow will be as follows:
- the server sends 10 tasks from jobA to the node
- the server then send 10 tasks from jobB to the node
- then again 10 tasks from jobA
- etc ...
So, in a sense, this could be seen as a distributed preemptive multitasking mechanism.
I hope this clarifies.