question: public void write ( CeylonConfig config , File source , OutputStream out ) throws IOException { if ( source . isFile ( ) ) { InputStream in = null ; try { in = new FileInputStream ( source ) ; write ( config , in , out ) ; } finally { if ( in != null ) { try { in . close ( ) ; } catch ( IOException e ) { } } } } else { throw new FileNotFoundException ( "Couldn't open source configuration file" ) ; } }
target:  Reads config from the given source file, updating it using the given  configuration and writing in to the given output.