code: @Override
      public void visit(
                  final int version,
                  final int access,
                  final String name,
                  final String signature,
                  final String superName,
                  final String[] interfaces)
      {
          String p = getGroupKey(name);
          current = groups.get(p);
          if (current == null)
          {
              current = new HashMap<>();
              groups.put(p, current);
          }
  
          if (signature == null)
          {
              if (superName != null)
              {
                  addInternalName(superName);
              }
              addInternalNames(interfaces);
          }
          else
          {
              addSignature(signature);
          }
      }
docs: ClassVisitor