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Understand GraphQL Java – Without Spring Getting in the Way
Rating: 4.6 out of 5(11 ratings)
302 students

Understand GraphQL Java – Without Spring Getting in the Way

Deep hands-on dive into the graphql-java library. Really understand graphql without Spring-ish noise.
Created byBenjamin Habegger
Last updated 11/2025
English
English [Auto],

What you'll learn

  • Understand the basics of GraphQL (schema, data fetchers)
  • Know how to write a GraphQL schema using the schema definition language (SDL)
  • Know how to write and wire DataFetchers
  • Know how to unit test a GraphQL engine
  • Know how to expose a GraphQL engine over HTTP using Jetty
  • Know how to create a DataFetcher for data from an SQL database
  • Get an in depth understanding of all GraphQL Schema types and how to wire them
  • Understand how GraphQL schema introspection works
  • Have in in depth understanding of querying a GraphQL API
  • Understand how to evolve a GraphQL schema
  • Understand how to generate all or parts of a schema through code
  • Know how to extend a GraphQL engine using instrumentations
  • Understand the execution workflow of a GraphQL query
  • Know how to optimize performance by using batch loading

Course content

14 sections • 31 lectures • 7h 23m total length

  • Introduction7:15

    Understand why GraphQL over REST and how to build a Java GraphQL server with the GraphQL Java library, using schema and data fetchers for single, precise queries.

  • Setting up the environment for a new GraphQL project7:53

    In this session we will simply be setting up our environment to work through the course. We'll be setting up the pom file with the dependencies we'll be using at the beginning. If you already know maven, you can just bring download the attached pom.xml

Requirements

  • Java programming skills is a minimal requirement

Description

Tired of bloated frameworks just to get started with GraphQL in Java?

In this course, you’ll learn how to build powerful GraphQL servers using the official graphql-java library — no Spring Boot, no extra layers, just clean, modular Java code.

This is a deep dive, designed to give you full control and understanding of how GraphQL really works in Java — from schema creation to execution, resolvers, and query optimization.

You’ll build a fully functional GraphQL service from scratch, using real database integration and hands-on exercises throughout.

What You'll Learn:

  • Build GraphQL servers in Java using the production-grade graphql-java library

  • Define your schema using SDL (Schema Definition Language) and via Java code

  • Implement DataFetchers (resolvers) — both synchronous and asynchronous

  • Wire resolvers with your schema manually, for full control

  • Connect your GraphQL service to a real database

  • Expose your service over HTTP with an embedded GraphiQL GUI

  • Use all major GraphQL constructs: queries, mutations, fragments, enums, interfaces, unions

  • Understand schema introspection and how clients use it

  • Dive into query execution internals in GraphQL Java

  • Optimize performance with batch loading techniques

How You’ll Learn:

  • Gentle step-by-step presentation of the GraphQL concepts

  • Hands-on examples and exercises in each section

  • A complete backend project you can adapt to your own use case

  • A modular teaching style that helps you master each piece of the GraphQL puzzle

Who this course is for:

  • Java developers wanting to learn how to build a GraphQL service

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