code: private void getDescriptor(final StringBuilder buf) {
          if (this.buf == null) {
              // descriptor is in byte 3 of 'off' for primitive types (buf ==
              // null)
              buf.append((char) ((off & 0xFF000000) >>> 24));
          } else if (sort == OBJECT) {
              buf.append('L');
              buf.append(this.buf, off, len);
              buf.append(';');
          } else { // sort == ARRAY || sort == METHOD
              buf.append(this.buf, off, len);
          }
      }
docs: Appends the descriptor corresponding to this Java type to the given
  string buffer.
  
  @param buf
  the string buffer to which the descriptor must be appended.