Practical Java guides, tutorials, and examples
Data Structures and Algorithms
Data structures, algorithms, and interview problems in Java.
+12 moreNeetcode 250 (Java)
The NeetCode 250 problem set, grouped by the same categories as the NeetCode roadmap, each solved in Java with a brute force and an optimal solution.
+14 moreJava Deep Dive
Modern Java (21 and 25), concurrency, the Java Memory Model, atomics and lock-free code, JVM internals, JIT, garbage collectors, performance tooling, and low-latency Java for big tech, fintech, and trading interviews.
+18 moreLow-Level Design
Low-level and object-oriented design in Java: modeling domains with classes, records and sealed types, design principles, concurrency-aware components, and classic interview problems (LRU cache, parking lot, elevator, and more), worked end to end with compiled code.
- Foundations and Interview Framework
- Design Principles
- Concurrent Components
- Data-Structure-Centric Problems
System Design
System design from fundamentals to interview problems: networking, storage, caching, distributed systems, microservices, and worked designs.
+13 moreDatabases and SQL
Learn SQL, schema design, indexes, transactions, and query tuning with tested PostgreSQL examples and interview questions.
+3 moreRust Programming
Learn Rust from Hello, world to unsafe, macros, and async internals.
+15 moreMaster Tokio Runtime
Learn Tokio from zero to advanced: async basics, tasks, timers, channels, networking, streams, the scheduler and reactor internals, production practices, 27 practical projects, and interview questions.
+6 moreAxum Microservices
Build and run production microservices in Rust with Axum.
+8 moreEssential Crates
The crates most Rust projects use.
+2 morePractical Examples
Complete Rust programs, built step by step.
+8 moreEssential Commands for Developers
The command-line tools developers use every day, with many real examples: files, pipes, variables, find, grep, sed, awk, xargs, jq, processes, permissions, curl, ports, SSH, rsync, git, archives, tmux, shell scripts, and the JDK tools.
+2 moreLocal LLMs and Coding Agents in Java
Run language models on your own machine and build a coding agent in Java: tokenizers, transformers, sampling, quantization, GGUF and Hugging Face, llama.cpp and vLLM, inference engineering, an inference engine in pure Java, and an Ollama-style CLI with picocli that downloads models, chats, and writes, runs, and fixes code with tools.
- How LLMs Work
- Hardware, Numbers, and Quantization
- Model Files and Hugging Face
- The loop CLI and Model Management
Staff Engineer System Design
Staff (L6) system design: the evaluator lens, the Staff decision loop, the five core primitives, fifteen production system blueprints from rate limiting to collaborative editing, and interview pacing, evaluation signals, and controversial opinions.
- Thinking Like a Staff Engineer
- Distributed Rate Limiting and Abuse Defense
- Mission-Critical Payment Gateway and Double-Entry Ledger
- Flash Sales and High-Contention Inventory
Inference Engineering
Serve generative AI models fast, cheaply, and reliably: LLM and image model mechanics, compute and memory bottlenecks, GPUs, CUDA and inference engines, quantization, speculative decoding, KV caching, parallelism, disaggregation, speech and vision models, autoscaling, multi-cloud production, and interview questions.
+5 moreLLM Fundamentals
The key concepts behind modern AI explained for beginners: AI, machine learning, and neural networks, large and small language models, vision-language and multimodal models, frontier models and AGI, parameters and weights, tokens and tokenizers, the context window, and what goes into a model's context.
+6 more