question: @ NotNull public static String normalize ( @ NotNull String path ) { int start = 0 ; boolean separator = false ; if ( SystemInfo . isWindows ) { if ( path . startsWith ( "//" ) ) { start = 2 ; separator = true ; } else if ( path . startsWith ( "\\\\" ) ) { return normalizeTail ( 0 , path , false ) ; } } for ( int i = start ; i < path . length ( ) ; ++ i ) { final char c = path . charAt ( i ) ; if ( c == '/' ) { if ( separator ) { return normalizeTail ( i , path , true ) ; } separator = true ; } else if ( c == '\\' ) { return normalizeTail ( i , path , separator ) ; } else { separator = false ; } } return path ; }
target:  converts back slashes to forward slashes removes double slashes inside the path, e.g. "x/y//z" => "x/y/z"