Apparently a J-hop is a bunnyhop.
You may need to either - Tilt your bars back, put stackers under your stem, buy new, higher bars, or buy a new, higher stem, or any combination of those, in order of how much of a faff it is.
How new are you to trials? If you are used to a trials bike, this should be easy to bunny hop and a spec alteration will more likely be the solution.
If you are new to trials, it could be technique too.