Java Lab
Senior-level Java lessons with a live code editor. Built for interview preparation, not beginner tutorials.
Core Java & OOP
2 lessons
Object model, inheritance, SOLID, generics, and immutability.
Collections & Data Structures
10 lessons
ArrayList, HashMap internals, TreeMap, Sets, Deque, PriorityQueue, and contracts.
Functional Java & Streams
6 lessons
Lambdas, stream pipelines, collectors, Optional, and parallel streams.
Concurrency & Multithreading
10 lessons
Thread lifecycle, locks, atomic variables, executors, and CompletableFuture.
JVM Internals & Performance
2 lessons
ClassLoader, GC algorithms, memory leaks, String pool, and JIT compilation.
Design Patterns (Java)
2 lessons
Singleton, Builder, Factory, Strategy, Observer, Decorator, and Proxy patterns.
Spring Boot & Production Patterns
9 lessons
Dependency injection, bean lifecycle, MVC, WebFlux, transactions, and security.
Common Interview Coding Patterns
15 lessons
Two pointers, frequency maps, monotonic stack, binary search, BFS/DFS, DP, LRU cache.