gistfile1.clj

(defprotocol PRandomAccessFile
  ""
  (close [obj] "")
  (position ([obj] [obj newpos]) ""))

(deftype RandomAccessBufferedFile
  [#^java.nio.channels.FileChannel channel
   #^java.nio.ByteBuffer buffer
   #^long bufstart]
  PRandomAccessFile
  (close [] (.close channel))
  (position ([] (.position channel))
	    ([newpos] (.position channel newpos))))

Results in: 

Unknown location:
  error: java.lang.IllegalArgumentException: params must be Symbols (rabfile.clj:15)