The proof!
Version 1.6
With a heapsize of 768mb jSunnyreports can barely run and process my testset.
Version 1.7
This is version 1.7 using the exact same set of data and is configured identically. This alpha version produces the exact same output. And yes, it runs in a default JVM with a configured heap of 64mb and has even room to spare!
Conclusion
WOW!