Advanced

Advanced Java tutorials for developers who’ve mastered the fundamentals. Design patterns, testing strategies, and professional development practices.

Java Design Patterns

Design patterns are reusable solutions to common programming problems. They’re not code you copy and paste, but templates for structuring […]

Unit tests verify that individual pieces of your code work correctly. They catch bugs early, make refactoring safer, and serve

Logging is how your application tells you what happened when you weren’t watching. Good logs help you debug problems, track

Dependency Injection (DI) is a design pattern where objects receive their dependencies from external sources rather than creating them internally.

NullPointerException is Java’s most common runtime error. Tony Hoare, who invented null references, called it his “billion-dollar mistake.” Java 8

Java 17 introduced records and sealed classes as standard features. Records eliminate boilerplate for simple data classes. Sealed classes restrict