public JCNewClass build() {
    // Generate a subclass of Callable
    ListBuffer<JCTree> classBody = new ListBuffer<JCTree>();
    int numParams = paramLists.getParameters().size();
    int minimumParams = 0;
    for (Parameter p : paramLists.getParameters()) {
      if (p.isDefaulted() || p.isSequenced()) break;
      minimumParams++;
    }
    boolean isVariadic = minimumParams != numParams;
    if (parameterListTree != null) {
      // generate a method for each defaulted param
      for (Tree.Parameter p : parameterListTree.getParameters()) {
        if (p.getDefaultArgument() != null || p.getDeclarationModel().isSequenced()) {
          MethodDefinitionBuilder methodBuilder =
              gen.classGen().makeParamDefaultValueMethod(false, null, parameterListTree, p);
          classBody.append(methodBuilder.build());
        }
      }
    }

    // collect each parameter type from the callable type model rather than the declarations to get
    // them all bound
    java.util.List<ProducedType> parameterTypes = new ArrayList<ProducedType>(numParams);
    if (forwardCallTo != null) {
      for (int i = 0; i < numParams; i++)
        parameterTypes.add(gen.getParameterTypeOfCallable(typeModel, i));
    } else {
      // get them from our declaration
      for (Parameter p : paramLists.getParameters()) parameterTypes.add(p.getType());
    }

    // now generate a method for each supported minimum number of parameters below 4
    // which delegates to the $call$typed method if required
    for (int i = minimumParams, max = Math.min(numParams, 4); i < max; i++) {
      classBody.append(makeDefaultedCall(i, isVariadic, parameterTypes));
    }
    // generate the $call method for the max number of parameters,
    // which delegates to the $call$typed method if required
    classBody.append(makeDefaultedCall(numParams, isVariadic, parameterTypes));
    // generate the $call$typed method if required
    if (isVariadic && forwardCallTo == null)
      classBody.append(makeCallTypedMethod(body, parameterTypes));

    JCClassDecl classDef =
        gen.make().AnonymousClassDef(gen.make().Modifiers(0), classBody.toList());

    JCNewClass instance =
        gen.make()
            .NewClass(
                null,
                null,
                gen.makeJavaType(typeModel, JT_EXTENDS | JT_CLASS_NEW),
                List.<JCExpression>of(gen.make().Literal(typeModel.getProducedTypeName(true))),
                classDef);
    return instance;
  }