Hey!
when you are building the java file, make sure to include the opencv jar file in your class path. An easy way to do this is to using the -cp command while building.
Doing this will work:
java -cp /home/pi/opencv/build/bin/opencv-310.jar TowerTracker.jar
This configures the class path to include the jar for OpenCV which is the error that you are facing. /home/pi/opencv/build/bin is the default location for the jar.
If you need any more help with this.
Feel free to PM me!
I went through this same process last week
