Multithreading with ORMLite and Derby

The AleHu client uses several threads in order to solve different tasks (create new message, receive packets, send packets, GUI handling, etc.) concurrently. When a user transmits big attachments (let's say larger than 100 MB), it happens occasionally that SQL exceptions are thrown. Those excpetions don't seem to harm (more testing is necessary), however I definitely would like to resolve those issues. In my opinion, a valid solution would be to use (thread-safe) pooled database connection sources (provided by ORMLite and apparently possible for Derby) for for each thread. However, further reading and tests are required.