Jump is just another name for the releases on Underground Construction. It evolved from chicago techno/house only less intelligent.

And since the hardstyle scene lacks inspiration/variation and keeps using old samples used in hardcore tracks, a lot of people are now getting bored with hardstyle and "discover" jump. So it gets popular and now the hardstyle labels see their incomes decreasing they also add jump to their releases..

And now they are going to milk this and exploit it.