question: public void serializeFormDef ( FormDef fd , String filepath ) { String hash = FileUtils . getMd5Hash ( new File ( filepath ) ) ; File formDef = new File ( Collect . CACHE_PATH + File . separator + hash + ".formdef" ) ; if ( ! formDef . exists ( ) ) { FileOutputStream fos ; try { fos = new FileOutputStream ( formDef ) ; DataOutputStream dos = new DataOutputStream ( fos ) ; fd . writeExternal ( dos ) ; dos . flush ( ) ; dos . close ( ) ; } catch ( FileNotFoundException e ) { e . printStackTrace ( ) ; } catch ( IOException e ) { e . printStackTrace ( ) ; } } }
target:  Write the FormDef to the file system as a binary blog.