Unreachable Memory not freed

[Thorsten Goetzke]

Hello,

I am working on a closed source software that uses a patched version of 
apache-batik to display SVG-Documents one by one. If you keep loading 
and discarding some specific SVG-Documents memory consumption keeps on 
growing until it reaches more than 95% of the available memory. The 
application becomes unusable slow, very little memory gets freed, 
although the gc is constantly running. Sometimes an OutOfMemoryError 
gets thrown. I took memory snaphsots and analyzed them using jvisualvm 
and yourkit. These tools report the majority of the memory as unreachable.
I have tried different garbage collectors (G1,ConcurrentMarkSweep),
and different Versions of Java: 1.8_60;1.8_65;1.8_102, the issue is 
always reproducible.
Is there something i can do to debug this further? I am currently not 
able to reproduce this issue in a somewhat small self contained example.
I could provide gc-logs and the heap dump (about 1gb zipped) or any 
other debuging info if someone is interested.

Best Regards,
Thorsten Goetzke