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This directory contains Java programming language study materials, sample applications, and framework implementations. Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible.

• Spring: Enterprise-grade framework for building Java applications
  • Spark with Hadoop: Apache Spark with Hadoop integration examples
  • Spark with Beam: Apache Beam data processing pipelines

• Samples: Core Java language examples and utilities
  • Data structures and algorithms implementations
  • Concurrency and threading examples
  • File I/O and data processing utilities
  • REST client implementations
  • Game implementations (PingPong, RubiksCube)

• HIVE: Thermostat monitoring demo comparing Reactive Stack vs Virtual Threads

• Yelp AI Assistant: Yelp-style AI assistant implementation in Java (Spring Boot)

• Java Development Kit (JDK) 11 or higher
• Maven 3.6+ for dependency management
• IDE of choice (IntelliJ IDEA, Eclipse, VS Code)

1. Install Java JDK

   # On Ubuntu/Debian
   sudo apt update
   sudo apt install openjdk-11-jdk
   
   # On macOS with Homebrew
   brew install openjdk@11
   
   # Verify installation
   java -version
   javac -version

2. Install Maven

   # On Ubuntu/Debian
   sudo apt install maven
   
   # On macOS with Homebrew
   brew install maven
   
   # Verify installation
   mvn -version

cd java/samples
mvn compile
mvn exec:java -Dexec.mainClass="Application"

cd java/spring/spark-hadoop
mvn clean install
mvn exec:java -Dexec.mainClass="HadoopSparkApplication"

Each sample in the samples/ directory can be compiled and run independently:

# Compile a specific Java file
javac samples/Application.java

# Run the compiled class
java -cp samples Application

Navigate to the specific Spring project directory and use Maven commands:

cd java/spring/spark-beam
mvn spring-boot:run

java/
├── README.md                 # This file
├── samples/                  # Pure Java language examples
│   ├── Application.java      # Main application example
│   ├── Combination.java      # Combinatorial algorithms
│   ├── SortingAlgorithms.java # Sorting implementations
│   ├── StringManipulations.java # String processing utilities
│   ├── pom.xml              # Maven configuration
│   └── ...                  # Additional Java samples
└── spring/                  # Spring framework examples
    ├── spark-hadoop/        # Spark + Hadoop integration
    └── spark-beam/          # Apache Beam pipelines

• Core Java Concepts: OOP principles, collections, generics, lambdas
• Concurrency: Thread management, executors, concurrent collections
• I/O Operations: File handling, streams, serialization
• Network Programming: REST clients, socket programming
• Data Processing: Algorithms, data structures, stream processing
• Framework Integration: Spring ecosystem, Apache Spark, Apache Beam

1. Code Style: Follow Java naming conventions and coding standards
2. Documentation: Include javadoc comments for public methods and classes
3. Testing: Write unit tests using JUnit for new functionality
4. Dependencies: Use Maven for dependency management
5. Examples: Provide clear, runnable examples with sample data

1. Place pure Java examples in the samples/ directory
2. Add framework-specific examples in appropriate subdirectories under their framework folder
3. Update this README with new content descriptions
4. Ensure all code compiles and runs successfully

• Use meaningful variable and method names
• Include error handling where appropriate
• Follow the single responsibility principle
• Write clean, readable code with appropriate comments

• Official Java Documentation
• Spring Framework Documentation
• Apache Spark Documentation
• Apache Beam Documentation
• Maven Documentation
• Java Tutorials by Oracle