A structured path through Java — starting with the language fundamentals, through OOP, the Collections Framework, concurrency, then Spring Boot and testing. Written for devs who actually want to understand the JVM, not just copy boilerplate.
Types, control flow, methods, and how the JVM actually works.
Primitives, wrapper types, operators, control flow, and methods. The stuff that trips you up in interviews.
String pool, immutability, StringBuilder, and array manipulation patterns.
Classes, inheritance, polymorphism, and the 4 pillars done right.
Classes, objects, inheritance chains, interfaces vs abstract classes, and when to use each.
What SOLID actually means in practice with concrete Java examples, not blog-post definitions.
Factory, Builder, Strategy, Observer — patterns that appear in interviews and production code.
The most asked-about Java topic in interviews.
List, Set, Map, Deque — when to use which, and what the backing data structure actually costs you.
Type erasure, bounded wildcards (? extends T vs ? super T), and why raw types are a code smell.
Threads, locks, executors, and the Java memory model.
Thread lifecycle, Runnable vs Callable, daemon threads, and thread-safe data structures.
ExecutorService, CompletableFuture, locks, semaphores, and CountDownLatch with real use cases.
End of roadmap
You've covered all 9 topics in the Java roadmap.