JTopologyBuilder uses a JFolder in order to separate the parent from the child so they both can be recycled. This is no longer necessary thanks to pool forwarding. Pool forwarding was implemented for multilevel event source topologies, but has only been used with custom topologies so far. Using the no-op JFolder probably comes with a small performance hit and large user confusion because the topology JANA2 reports doesn't match the slide decks.
JTopologyBuilder uses a JFolder in order to separate the parent from the child so they both can be recycled. This is no longer necessary thanks to pool forwarding. Pool forwarding was implemented for multilevel event source topologies, but has only been used with custom topologies so far. Using the no-op JFolder probably comes with a small performance hit and large user confusion because the topology JANA2 reports doesn't match the slide decks.