throw new Error ("Not implemented");
if (! tryLockImpl(position, size, shared)) return null;  boolean completed = false;  try { boolean lockable = tryLockImpl(position, size, shared); completed = true; return (lockable ? new FileLockImpl(fd, this, position, size, shared) : null); } finally { end(completed); }
  public FileLock tryLock (long position, long size, boolean shared)    throws IOException  {    if (position < 0        || size < 0)      throw new IllegalArgumentException ();    if (!isOpen ())      throw new ClosedChannelException ();    throw new Error ("Not implemented");  }