I am J1b1a1, which Eupedia says was absent in Europe until the Bronze Age, but was likely brought with the Steppe invaders into Europe, and featured in many bronze age proto celtic cultures such as Urnfield. J1b1 is apparently the only J1b sub-branch which is found primarily in Europe, with the others being more common in the Middle East.
When I go to Wikipedia (not the font of all knowledge, I know) they don't mention any J1b1 being found in the Bronze Age cultures mentioned on the Eupedia page though (such as Urnfield, Catacomb and Unetice), so it would be nice to get the sources for this as I'm sure whoever wrote the Eupedia page was correct, would just be great to read the papers that confirm it all.