Jon Jones -- Still Gunning for UFC 197 Victory ... 'I've Trained Too Hard'

Despite his legal issues ... and the fact he's currently behind bars ... Jon Jones is still confident he'll beat up Daniel Cormier at UFC 197 on April 23rd.

Sources close to the UFC superstar tell us he's taking his legal matters VERY seriously -- but isn't brushing off his fight with D.C. He's planning on jumping right back into his training regimen as soon as he gets out of jail.

In fact, Jones tweeted about the fight late Monday night ... saying, "Today I had some of the best workouts I've had all camp. I've trained too hard and come too far to let anything get to me at this point."