do you see any conceptual problems porting the java code from the miniball project to perl?

There shouldn't be, but ... without a clear understanding of the algorithm, good luck trying to debug the beast.

And then there is the problem of performance. If you go for a brute-force conversion retaining the same matryoshka doll construction of nested classes -- and you'd probably have to -- the performance would be abysmal written in Perl.

You'd almost certainly be better off using the C++ version to build a shared library and then write an XS/C wrapper to the primary entry point(s).

You could -- theoretically -- wrap over the full API into a Perl class, but then you'd have the problem of C++ name mangling.