What Should A Java Developer Learn In 2024?

For a Java developer in 2024, the learning roadmap prioritizes

cloud-native development, advanced language features, modern frameworks, and robust DevOps practices. Staying current with the rapid release cycle of the Java Development Kit (JDK) and the broader ecosystem is key to building high-performance, scalable, and secure applications for the future.

1. Core Java and the latest JDK features

While foundational Java knowledge is a given, mastery of the latest JDK versions is crucial for writing clean, high-performance code.

• Java 17 (LTS) and Java 21 (LTS): You should be fully proficient with features introduced in recent long-term support releases, including:
  • Records: A concise syntax for creating transparent, immutable data-carrier classes.
  • Sealed Classes: Enables the creation of class hierarchies with restricted inheritance, providing more control and clarity.
  • Pattern Matching: Simplifies conditional logic by allowing instanceof checks with automatic type casting.
  • Text Blocks: Provides a simple way to define multi-line string literals, improving code readability.
• Project Loom and Virtual Threads: Understand virtual threads, which are a lightweight, high-throughput concurrency model. This new approach simplifies asynchronous programming and significantly improves application scalability.
• Project Valhalla and Value Types: Keep an eye on Project Valhalla, which aims to introduce value types for more efficient data structures and better performance.

2. Frameworks and microservices

In modern enterprise development, using frameworks is standard practice. Knowing which frameworks to use and how to apply a microservices architecture is paramount.

• Spring and Spring Boot 3: The Spring ecosystem remains the de facto standard for enterprise Java. Spring Boot simplifies the creation of production-ready, stand-alone Spring applications.
  • Learn reactive programming with Spring WebFlux.
  • Be proficient with the latest version, which offers enhanced support for GraalVM native images for faster startup times and lower memory usage.
• Quarkus and Micronaut: For cloud-native and microservices development, frameworks like Quarkus and Micronaut are gaining traction due to their low memory footprint and extremely fast startup times.
• Microservices Architecture: Master the principles of designing, developing, and deploying microservices. This includes knowledge of service discovery (e.g., Netflix Eureka, Consul) and communication protocols (e.g., RESTful APIs, gRPC).
• Jakarta EE: For developers working on traditional enterprise applications, staying current with the Jakarta EE specifications is still relevant.

3. Cloud-native and DevOps

The shift to the cloud is irreversible. A modern Java developer needs skills that support this environment.

• Cloud Platforms: Gain experience with at least one major cloud provider (AWS, GCP, or Azure). Understand their core services related to computing, storage, and databases.
• Containerization (Docker) and Orchestration (Kubernetes): These tools are essential for building and deploying scalable applications. Learn to:
  • Create efficient Docker images for your Java applications.
  • Deploy, manage, and scale containerized applications on Kubernetes.
• CI/CD (Continuous Integration/Continuous Deployment): Automate your build, test, and deployment processes with tools like Jenkins, GitLab CI, or GitHub Actions.
• Infrastructure as Code (IaC): Learn how to define and manage infrastructure using code with tools like Terraform.

4. Testing and observability

As systems become more distributed and complex, strong testing and monitoring skills are no longer optional.

• Unit Testing: Beyond the fundamentals of JUnit 5, become proficient with mocking frameworks like Mockito to isolate and test code effectively.
• Integration Testing: Leverage tools like Testcontainers to spin up real service dependencies (databases, message queues) for more reliable integration tests.
• Observability: Implement robust monitoring, tracing, and logging to ensure the health and performance of applications.
  • Logging: Use standard frameworks like SLF4J with Logback.
  • Metrics: Employ Micrometer to track key performance indicators.
  • Distributed Tracing: Utilize OpenTelemetry to trace requests across microservices.
• Monitoring Tools: Get familiar with platforms like Prometheus and Grafana for visualizing metrics.

5. Security best practices

With an increasing number of cyber threats, security must be a priority from day one.

• Secure Coding: Practice input validation, secure session management, and proper exception handling.
• Dependency Management: Regularly scan for known vulnerabilities in your third-party libraries using tools like OWASP Dependency-Check or Snyk.
• Authentication and Authorization: Master modern security mechanisms using frameworks like Spring Security, including OAuth 2.0 and JSON Web Tokens (JWT).

6. AI and data

The fields of AI and data science are rapidly growing, and Java has a strong role to play, particularly in the enterprise.

• AI/ML Libraries: Explore Java libraries for machine learning, such as Deeplearning4j, and understand how to integrate ML models into Java applications.
• Data Processing: Learn about big data processing frameworks like Apache Spark.
• Generative AI: Understand how to integrate with and apply generative AI models, for example, by using prompt engineering for better developer productivity.
• Databases: Stay current with both relational databases (SQL) and NoSQL databases like MongoDB.

7. Productivity and mindset

Beyond specific technologies, adopting the right mindset and using the best tools can have a massive impact on your career.

• IDE Proficiency: Master your chosen IDE (IntelliJ IDEA is the market leader), including its refactoring tools, debugger, and plugins.
• Code Quality: Adhere to clean coding practices, follow the SOLID principles, and participate in regular code reviews.
• Continuous Learning: Engage with the Java community by following influential blogs (e.g., Baeldung, Foojay) and attending meetups. The Java ecosystem is mature, but it is also constantly evolving.