question: public synchronized boolean acquire ( ) throws ReplicatorException { if ( isLocked ( ) ) return true ; try { raf = new RandomAccessFile ( lockFile , "rw" ) ; FileChannel channel = raf . getChannel ( ) ; lock = channel . tryLock ( ) ; } catch ( FileNotFoundException e ) { throw new ReplicatorException ( "Unable to find or create lock file: " + lockFile . getAbsolutePath ( ) ) ; } catch ( Exception e ) { throw new ReplicatorException ( "Error while attempting to acquire file lock: " + lockFile . getAbsolutePath ( ) , e ) ; } finally { if ( lock == null && raf != null ) { close ( raf ) ; } } if ( lock == null ) { if ( raf != null ) close ( raf ) ; return false ; } else if ( lock . isShared ( ) ) { release ( ) ; return false ; } else return true ; }
target:  Attempt to acquire write lock. This call is idempotent.