A gotcha with fcntl file locking
Today I ran into an issue with fcntl(2) file locking  on Linux. A little research confirmed my fear:
The worst part however is that POSIX locks are automatically released if a process calls
close()on any (!) of its open file descriptors for that file.
The whole post is well worth a read.
 Which is what OpenJDK uses for FileChannel#lock.
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