Hi
Apple Java is NOT supported by Java3D 1.6.0 and later, this is explained in the Java3D 1.6/1.7 user's guide. Please use OpenJDK or Oracle Java instead of Apple Java. I remind you that Apple Java has been deprecated for several years. Moreover, you might have to switch to Java3D 1.7 to avoid some conflicts with an obsolete version of Java3D (1.3?) installed by Apple on your operating system with some obsolete versions of JOGL (1.1?) and GlueGen.
Maybe Phil is right, you should use JOGL 2.3.2 with Java3D 1.6 but it might not be enough.