code: public int getNameAndTypeIndex(String name, String descriptor)
      {
          for (ConstantInfo ci : listConstantInfo(NameAndType.class))
          {
              NameAndType nat = (NameAndType) ci;
              int nameIndex = nat.getName_index();
              String str = getString(nameIndex);
              if (name.equals(str))
              {
                  int descriptorIndex = nat.getDescriptor_index();
                  String descr = getString(descriptorIndex);
                  if (descriptor.equals(descr))
                  {
                      return constantPoolIndexMap.get(ci);
                  }
              }
          }
          return -1;
      }
docs: Returns the constant map index to name and type
  @param name
  @param descriptor
  @return