Learn JAVA with Real Code Examples

Updated Nov 17, 2025

Introduction & Fundamentals Setup & Configuration Architecture & Deep Internals Performance & Security Development Workflow Learning & Career Growth Business & Strategy Examples

Practical Examples

Build a REST API with Spring Boot

Develop Android applications

Create multithreaded systems

Build microservices deployed on cloud

Troubleshooting

Fix classpath/module issues

Resolve NullPointerExceptions

Handle memory leaks or GC tuning

Fix Maven/Gradle dependency conflicts

Testing Guide

Unit tests with JUnit

Mocking with Mockito

Integration tests with Spring Test

Load testing with JMeter

Deployment Options

JAR/WAR deployment

Dockerized containers

Kubernetes clusters

Cloud deployment with AWS/GCP/Azure

Tools Ecosystem

Spring Boot

Hibernate/JPA

Maven/Gradle

JUnit 5

IntelliJ IDEA

Integrations

MySQL/PostgreSQL

Kafka and RabbitMQ

Redis caching

Docker/Kubernetes

Cloud providers: AWS, GCP, Azure

Productivity Tips

Use IntelliJ shortcuts

Use Lombok for boilerplate

Use records for data models

Automate builds with Gradle

Challenges

Build a multithreaded chat server

Build a Spring Boot e-commerce API

Create a Kafka event-driven system

Implement your own library with generics