code: public static final String asString(WsByteBuffer[] list, int[] positions, int[] limits) {
          byte[] data = asByteArray(list, positions, limits);
          return (null != data) ? new String(data) : null;
      }
docs: Convert an array of buffers to a string using the input starting positions
  and ending limits.
  
  @param list
  @param positions
  @param limits
  @return String