In [1] it was noticed, that encrypting huge streams result in OOMs. This was due to cached ByteBuffers of NIO channels, which were necessary because of mmap problems in Windows. I've introduced now a release method, to unmap buffers, which aren't used anymore. So unmapping makes only sense in stream like handling, where buffers aren't revisited anymore. [1] https://stackoverflow.com/questions/61463301/apache-poi-throwing-oom-error-when-trying-to-password-protect-modest-sized-xlsx
Applied via r1877144