I'm currently studing threads in java / android, and i'm wondering if is there anything that cant be done in a non main thread? For example i know that all UI can't be done. Thanks
It depends on what your are doing in any multi-threaded environment (like the Linux kernel). Java GUI and many other components are not guaranteed to be thread-safe. The main limitation are resource sharing in threads (IPC ends points, variables, etc.. are shared, that can easily cause thread dead-locks (blocks) without careful programming) vs independent address and resource space in processes in a single main thread.