Learn JAVA with Real Code Examples
Updated Nov 17, 2025
Architecture
Source code -> bytecode via javac
JVM executes bytecode
JIT and HotSpot optimize runtime
Modular architecture (Java 9+)
Rendering Model
Compiled to bytecode
Executed by JVM
Optimized via JIT compiler
Uses modular runtime (Java 9+)
Architectural Patterns
Spring Boot layered architecture
Hexagonal architecture
Event-driven microservices
Domain-driven design
Real World Architectures
Spring Boot microservices
Banking/fintech transaction systems
Distributed enterprise apps
Android app architectures
Design Principles
Write once, run anywhere
Strong typing
Backwards compatibility
Memory safety via GC
Scalability Guide
Use connection pooling
Use microservices with Spring Cloud
Integrate Kafka for event systems
Scale horizontally via Kubernetes
Migration Guide
Refactor legacy Java 8 to modern Java 17+
Replace old threads with executors
Use records instead of POJOs
Modularize large codebases