Once you know Java, you need to understand how it communicates with the internet.

Before touching the web, you must master the language's core. Strong fundamentals distinguish "copy-paste" developers from true problem solvers.

Java syntax, variables, and primitive vs. reference types.

Professional projects use Maven or Gradle to manage dependencies and automate builds.

Modern alternatives optimized for cloud-native and serverless environments (faster startup times and lower memory usage).

The heart of Java. You must understand Classes, Objects, Inheritance, Polymorphism, Abstraction, and Encapsulation.