I think you haven't setup your library folder appropriately.
Can you show me what your project folder looks like so that I can compare it?
If you haven't provided a correct path to the
*.java library files, than, yes, you will end up having this problem.
Your project directory should look like this:
MyProject/ ===> com/ ===> dexterind/ ===> gopigo/ ===> [all library files]
And when you compile you do need this following line of commands:
sudo -p mkdir ./bin
sudo javac -d ./bin -classpath .:classes:/opt/pi4j/lib/'*' ./MyProject.java /src/com/dexterind/gopigo/*.java ./src/com/dexterind/gopigo/behaviours/*.java ./src/com/dexterind/gopigo/components/*.java ./src/com/dexterind/gopigo/events/*.java ./src/com/dexterind/gopigo/utils/*.java;