Tracer

FarrukhMasud said:

java.lang.UnsatisfiedLinkError: org.odejava.ode.OdeJNI.get_PARENTSPACEID_ZERO()J

Please advise what should I do

Looks like you use the wrong natives (odejava.dll/so/jnilib) - probably you have an odejava library somewhere in the path or you specified a wrong java.library.path (search for java.library.path to find more info on this).
But you don't need to use physics for your tracer. Have a look at the code adapgp posted in this thread - that should get you started.