code: private static boolean isValidEscaping(char c) {
          return ((c == 'n') || (c == 'r') || (c == 't') || (c == 'f') || (c == 'b') || (c == '\\') || (c == '/')
                  || (c == '"') || (c == 'u'));
      }
docs: Check that char c (which is preceded by a backslash) is a valid escape
  sequence.
  
  @param c
  @return