java-expert

Virtual threads in Java 21 enable high-throughput concurrency for I/O-bound tasks by allowing lightweight thread creation. You can refactor existing methods to replace platform threads, improving application scalability without changing APIs.

Tuning JVM performance with G1GC or ZGC involves optimizing memory management and garbage collection to reduce latency. You can use Java Flight Recorder (JFR) to analyze runtime behavior and identify bottlenecks for targeted optimizations.

Hexagonal Architecture in Java isolates core business logic from external interfaces using ports and adapters. Implementing this pattern with modern Java features like Records and Sealed Classes ensures clean, maintainable, and testable code structures.

JUnit 5 combined with Testcontainers supports automated integration testing by managing Docker containers for your test environments. AssertJ and Mockito further enhance test reliability by providing fluent assertions and mock management.

Java 21 pattern matching works seamlessly with sealed classes to enable exhaustive switch expressions. This combination allows the compiler to verify all possible cases are covered, reducing runtime errors and ensuring robust domain modeling.

Avoid virtual threads for CPU-bound computations where platform threads are more efficient, as virtual threads optimize blocking I/O operations. Heavy synchronization or long-held monitors can also negate their performance benefits.