question: public PathImpl createTempFile ( String prefix , String suffix ) throws IOException { if ( prefix == null || prefix . length ( ) == 0 ) prefix = "t" ; if ( suffix == null ) suffix = ".tmp" ; synchronized ( LOCK ) { for ( int i = 0 ; i < 32768 ; i ++ ) { int r = Math . abs ( ( int ) RandomUtil . getRandomLong ( ) ) ; PathImpl file = lookup ( prefix + r + suffix ) ; if ( file . createNewFile ( ) ) return file ; } } throw new IOException ( "cannot create temp file" ) ; }
target:  Creates a unique temporary file as a child of this directory.