Trying to use private method of parent

[yami12376]

https://github.com/howtographql/graphql-java/blob/master/src/main/java/com/howtographql/hackernews/GraphQLEndpoint.java

    public GraphQLEndpoint() {
        super(buildSchema());
    }

Currently, the buildSchema of SimpleGraphQLServlet is private - this code does not work.