JimFS doesn't handle file locks in documented way (OverlappingFileLockException)

[nick7ikin]

If I try to lock regular file then locking it the second time will raise OverlappingFileLockException as described in FileChannel documentation

JimFS allows to lock the same file multiple times. Here is a test code

    public void testJimfsLock() throws IOException {

        FileSystem jimFs = Jimfs.newFileSystem();
        FileSystem fs = FileSystems.getDefault();

        checkLock(jimFs.getPath("/lockfile"));
        checkLock(fs.getPath("/tmp/lockfile"));

    }

    private void checkLock(Path lockFilePath) throws IOException {
        System.out.println("lockFilePath=" + lockFilePath);
        FileChannel fileChannel = FileChannel.open(lockFilePath, StandardOpenOption.CREATE, StandardOpenOption.WRITE);
        FileLock lock1 = fileChannel.lock();
        FileLock lock2 = null;
        try {
            lock2 = fileChannel.tryLock();
        } catch (OverlappingFileLockException e) {
            System.out.println("got OverlappingFileLockException");
        }

        System.out.println("lock1=" + lock1);
        System.out.println("lock2=" + lock2);
    }

It will print the following output:

lockFilePath=/lockfile
lock1=com.google.common.jimfs.JimfsFileChannel$FakeFileLock[0:9223372036854775807 exclusive valid]
lock2=com.google.common.jimfs.JimfsFileChannel$FakeFileLock[0:9223372036854775807 exclusive valid]
lockFilePath=/tmp/lockfile
got OverlappingFileLockException
lock1=sun.nio.ch.FileLockImpl[0:9223372036854775807 exclusive valid]
lock2=null

As you see attempting to lock file for the second time on regular file system leads to OverlappingFileLockException.