Java Roadmap

A step-by-step Java roadmap: what to learn in order, the related skills and the best places to learn each step.

The stack, end to end

  • Backend: Java, Object-oriented programming, Collections, Exceptions, Maven or Gradle, Spring Boot, Spring Data JPA, Dependency injection, Spring Security
  • Database: SQL, SELECT and WHERE, JOINs, GROUP BY and aggregates, INSERT, UPDATE, DELETE
  • Testing: Unit testing, Integration testing, Test-driven development

  1. Java

    Suggested pace: Start here

    Java is widely used for enterprise and Android back ends. Learn the syntax, object-oriented programming, collections, exceptions, streams and a build tool such as Maven or Gradle.

    Skills

    • Java
    • Object-oriented programming
    • Collections
    • Exceptions
    • Maven or Gradle

    Tips

    • Write small console programs until classes and interfaces feel natural.

    Where to learn

  2. SQL basics

    Suggested pace: Next

    SQL is how you ask a relational database questions. Learn SELECT, WHERE, ORDER BY, GROUP BY, aggregate functions, joins and how to create, insert, update and delete data.

    Skills

    • SQL
    • SELECT and WHERE
    • JOINs
    • GROUP BY and aggregates
    • INSERT, UPDATE, DELETE

    Tips

    • Practise on real-looking data. Write the query by hand before using any tool that writes it for you.

    Where to learn

  3. Spring Boot

    Suggested pace: Then

    Spring Boot is the standard way to build Java back ends: REST controllers, dependency injection, data access with JPA, configuration, security and testing.

    Skills

    • Spring Boot
    • Spring Data JPA
    • Dependency injection
    • Spring Security

    Tips

    • Follow one official guide end to end, then rebuild it from memory.

    Where to learn

  4. Unit and integration testing

    Suggested pace: After that

    Automated tests catch mistakes early and let you change code with confidence. Learn to write unit tests, use mocks sensibly and test your API and database together.

    Skills

    • Unit testing
    • Integration testing
    • Test-driven development

    Tips

    • Write a test for every bug you fix so it cannot come back unnoticed.

    Where to learn

Frequently asked questions

Where should I start with Java?

Start at step 1 and work down in order, because later steps build on earlier ones. If you are signed in, the roadmap compares your resume with each step and marks where you could start.

Is Java worth learning?

Check how many job adverts in your area mention Java, and whether it fits the kind of work you want. This roadmap shows what to learn; the Browse jobs page shows what employers are asking for.

How do I know I am ready to apply?

When you can build a small project from start to finish without copying a tutorial, and explain why you made your choices. Apply while you keep learning; you do not need to know everything.