Java Technology Stack & Build System

Java v2 Development Environment

Build Tools & Dependencies

• Build System: Apache Maven
• Testing Framework: JUnit 5
• Build Plugin: Apache Maven Shade Plugin
• SDK Version: AWS SDK for Java v2
• Java Version: JDK 17

Common Build Commands

# Build and Package
mvn clean compile                 # Compile source code
mvn package                       # Build with dependencies
mvn clean package                 # Clean and build

# Testing
mvn test                          # Run all tests
mvn test -Dtest=ClassName         # Run specific test class
mvn test -Dtest=ClassName#methodName  # Run specific test method

# Execution
java -cp target/PROJECT-1.0-SNAPSHOT.jar com.example.Main
mvn exec:java -Dexec.mainClass="com.example.Main"

Java-Specific Pattern Requirements

File Naming Conventions

• Use PascalCase for class names
• Service prefix pattern: {Service}Action.java (e.g., S3ListBuckets.java)
• Hello scenarios: Hello{Service}.java (e.g., HelloS3.java)
• Test files: {Service}ActionTest.java

Hello Scenario Structure

• Class naming: Hello{Service}.java class with main method
• Method structure: Static main method as entry point
• Documentation: Include Javadoc explaining the hello example purpose

Code Structure Standards

• Package naming: Use reverse domain notation (e.g., com.example.s3)
• Class structure: One public class per file matching filename
• Method naming: Use camelCase for method names
• Constants: Use UPPER_SNAKE_CASE for static final variables
• Imports: Group imports logically (Java standard, AWS SDK, other libraries)

Error Handling Patterns

import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.core.exception.SdkException;
import software.amazon.awssdk.services.s3.model.S3Exception;

public class ExampleClass {
    public void exampleMethod() {
        try (S3Client s3Client = S3Client.builder().build()) { //For Hello examples, use Sync service clients. For Scenario examples or working with service client, use the Java Async client. 
            // AWS service call
            var response = s3Client.operation();
            // Process response
        } catch (S3Exception e) {
            // Handle service-specific exceptions
            System.err.println("S3 Error: " + e.awsErrorDetails().errorMessage());
            throw e;
        } catch (SdkException e) {
            // Handle general SDK exceptions
            System.err.println("SDK Error: " + e.getMessage());
            throw e;
        }
    }
}

Testing Standards

• Test framework: Use JUnit 5 annotations (@Test, @BeforeEach, @AfterEach)
• Integration tests: Mark with @Tag("IntegrationTest") or similar
• Resource management: Use Github standards for AWS clients
• Assertions: Use JUnit 5 assertion methods
• Test naming: Use descriptive method names explaining test purpose

Maven Project Structure

src/
├── main/
│   └── java/
│       └── com/
│           └── example/
│               └── {service}/
│                   ├── Hello{Service}.java
│                   ├── {Service}Actions.java
│                   └── {Service}Scenario.java
└── test/
    └── java/
        └── com/
            └── example/
                └── {service}/
                    └── {Service}Test.java

Documentation Requirements

• Class Javadoc: Include purpose, usage examples, and prerequisites
• Method Javadoc: Document parameters, return values, and exceptions
• Inline comments: Explain complex AWS service interactions
• README sections: Include Maven setup and execution instructions

Language-Specific Pattern Errors to Avoid

• ❌ NEVER assume class naming without checking existing examples
• ❌ NEVER use snake_case for Java class or method names
• ❌ NEVER forget to close AWS clients (use try-with-resources)
• ❌ NEVER ignore proper exception handling for AWS operations
• ❌ NEVER skip Maven dependency management

Best Practices

• ✅ ALWAYS follow the established Maven project structure
• ✅ ALWAYS use PascalCase for class names and camelCase for methods
• ✅ ALWAYS use try-with-resources for AWS client management
• ✅ ALWAYS include proper exception handling for AWS service calls
• ✅ ALWAYS follow Java naming conventions and package structure
• ✅ ALWAYS include comprehensive Javadoc documentation

Maven Configuration Requirements

• AWS SDK BOM: Include AWS SDK Bill of Materials for version management
• Compiler plugin: Configure for appropriate Java version
• Shade plugin: For creating executable JARs with dependencies
• Surefire plugin: For test execution configuration

Integration with Knowledge Base

Before creating Java code examples:

1. Query coding-standards-KB for "Java-code-example-standards"
2. Query Java-premium-KB for "Java implementation patterns"
3. Follow KB-documented patterns for Maven structure and class organization
4. Validate against existing Java examples only after KB consultation