Java Hello Examples Generation

MANDATORY: Knowledge Base Consultation (FIRST STEP)

🚨 CRITICAL - Must be completed BEFORE any code generation

bash

# Step 1: List available knowledge bases
ListKnowledgeBases()

# Step 2: Query coding standards (REQUIRED)
QueryKnowledgeBases("coding-standards-KB", "Java-code-example-standards")

# Step 3: Query implementation patterns (REQUIRED)  
QueryKnowledgeBases("Java-premium-KB", "Java implementation patterns")

# Step 4: AWS service research (REQUIRED)
search_documentation("What is [AWS Service] and what are its key API operations?")
read_documentation("https://docs.aws.amazon.com/[service]/latest/[relevant-page]")

FAILURE TO COMPLETE KNOWLEDGE BASE CONSULTATION WILL RESULT IN INCORRECT CODE STRUCTURE

Purpose

Generate simple "Hello" examples that demonstrate basic service connectivity and the most fundamental operation using direct AWS SDK for Java V2 client calls.

Requirements

MANDATORY: Every AWS service MUST include a "Hello" scenario
Simplicity: Should be the most basic, minimal example possible
Standalone: Must work independently of other examples
Direct Client: Use AWS SDK client directly, no actions classes needed

File Structure

javav2/example_code/{service}/
├── src/main/java/com/example/{service}/
│   └── Hello{Service}.java         # Hello example file

Hello Example Pattern

java

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

package com.example.{service};

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.{service}.{Service}Client;
import software.amazon.awssdk.services.{service}.model.*;
import software.amazon.awssdk.core.exception.SdkException;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 *
 * This example shows how to get started with {AWS Service} by {basic operation description}.
 */

// snippet-start:[{service}.java2.hello.main]
public class Hello{Service} {

    public static void main(String[] args) {
        final String usage = """
                Usage:
                   <region>

                Where:
                   region - The AWS region (for example, us-east-1).
                """;

        if (args.length != 1) {
            System.out.println(usage);
            System.exit(1);
        }

        String region = args[0];
        Region awsRegion = Region.of(region);
        {Service}Client {service}Client = {Service}Client.builder()
                .region(awsRegion)
                .build();

        hello{Service}({service}Client);
        {service}Client.close();
    }

    /**
     * Invokes a {AWS Service} operation to {basic operation description}.
     *
     * @param {service}Client the {AWS Service} client to use for the operation
     */
    public static void hello{Service}({Service}Client {service}Client) {
        try {
            // Perform the most basic operation for this service
            {BasicOperation}Request request = {BasicOperation}Request.builder()
                    .build();

            {BasicOperation}Response response = {service}Client.{basicOperation}(request);

            System.out.println("Hello, {AWS Service}!");
            
            // Display appropriate result information
            if (response.has{ResultField}()) {
                System.out.println("Found " + response.{resultField}().size() + " {resources}.");
                response.{resultField}().forEach(resource -> 
                    System.out.println("  - " + resource.{resourceName}())
                );
            } else {
                System.out.println("{AWS Service} is available and ready to use.");
            }

        } catch ({Service}Exception e) {
            System.err.println("{AWS Service} error occurred: " + e.awsErrorDetails().errorMessage());
            System.exit(1);
        } catch (SdkException e) {
            System.err.println("SDK error occurred: " + e.getMessage());
            System.exit(1);
        }
    }
}
// snippet-end:[{service}.java2.hello.main]

Hello Examples by Service Type

List-Based Services (S3, DynamoDB, etc.)

Operation: List primary resources (buckets, tables, etc.)
Message: Show count and names of resources

Status-Based Services (GuardDuty, Config, etc.)

Operation: Check service status or list detectors/configurations
Message: Show service availability and basic status

Compute Services (EC2, Lambda, etc.)

Operation: List instances/functions or describe regions
Message: Show available resources or regions

Service-Specific Hello Examples

For Services with List Operations

java

public static void hello{Service}({Service}Client {service}Client) {
    try {
        List{Resources}Request request = List{Resources}Request.builder().build();
        List{Resources}Response response = {service}Client.list{Resources}(request);

        System.out.println("Hello, {AWS Service}!");
        System.out.println("Found " + response.{resources}().size() + " {resources}.");
        
        response.{resources}().forEach(resource -> 
            System.out.println("  - " + resource.{resourceName}())
        );

    } catch ({Service}Exception e) {
        System.err.println("{AWS Service} error: " + e.awsErrorDetails().errorMessage());
        System.exit(1);
    }
}

For Services with Status Operations

java

public static void hello{Service}({Service}Client {service}Client) {
    try {
        Get{Service}StatusRequest request = Get{Service}StatusRequest.builder().build();
        Get{Service}StatusResponse response = {service}Client.get{Service}Status(request);

        System.out.println("Hello, {AWS Service}!");
        System.out.println("Service status: " + response.status());
        System.out.println("{AWS Service} is ready to use.");

    } catch ({Service}Exception e) {
        System.err.println("{AWS Service} error: " + e.awsErrorDetails().errorMessage());
        System.exit(1);
    }
}

For Services with Describe Operations

java

public static void hello{Service}({Service}Client {service}Client) {
    try {
        Describe{Resources}Request request = Describe{Resources}Request.builder()
                .maxResults(10)
                .build();
        Describe{Resources}Response response = {service}Client.describe{Resources}(request);

        System.out.println("Hello, {AWS Service}!");
        System.out.println("Found " + response.{resources}().size() + " {resources}.");
        
        response.{resources}().forEach(resource -> 
            System.out.println("  - " + resource.{resourceId}() + " (" + resource.state() + ")")
        );

    } catch ({Service}Exception e) {
        System.err.println("{AWS Service} error: " + e.awsErrorDetails().errorMessage());
        System.exit(1);
    }
}

Error Handling Requirements

Standard Error Handling Pattern

java

try {
    // AWS operation
    response = {service}Client.operation(request);
    
} catch ({Service}Exception e) {
    // Service-specific errors
    String errorCode = e.awsErrorDetails().errorCode();
    switch (errorCode) {
        case "UnauthorizedOperation":
            System.err.println("You don't have permission to access {AWS Service}.");
            break;
        case "InvalidParameterValue":
            System.err.println("Invalid parameter provided to {AWS Service}.");
            break;
        default:
            System.err.println("{AWS Service} error: " + e.awsErrorDetails().errorMessage());
    }
    System.exit(1);
    
} catch (SdkException e) {
    // General SDK errors (network, credentials, etc.)
    System.err.println("SDK error: " + e.getMessage());
    System.exit(1);
}

Validation Requirements

✅ Must run without errors (with proper credentials)
✅ Must handle credential issues gracefully
✅ Must display meaningful output
✅ Must use direct AWS SDK client calls
✅ Must include proper snippet tags
✅ Must accept region as command line argument
✅ Must close client resources properly

Common Patterns

Always use {Service}Client.builder().region(awsRegion).build() for client creation
Include comprehensive error handling for both service and SDK exceptions
Provide user-friendly output messages
Handle command line arguments properly
Close client resources in main method
Keep it as simple as possible - no additional classes or complexity
Use proper Java naming conventions (PascalCase for classes, camelCase for methods)

Build Configuration

Ensure the service dependency is included in pom.xml:

xml

<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>{service}</artifactId>
    <version>${aws.java.sdk.version}</version>
</dependency>

Testing Requirements

✅ Must compile without errors
✅ Must run with valid AWS credentials
✅ Must handle invalid regions gracefully
✅ Must display appropriate output for empty results
✅ Must exit cleanly on errors