Jakarta EE HelloWorld Client Example

A comprehensive Jakarta EE 10 example demonstrating remote EJB invocation using OpenLiberty. This project showcases modern Jakarta EE development patterns including EJB remote interfaces, CDI, Jakarta Faces, and client-server communication.

📋 Project Overview

This example consists of three main components:

• HelloWorldServer: A Jakarta EE web application with EJB services
• HelloWorldClient: A standalone EJB client application
• HelloWorldClientEAR: An Enterprise Application Archive for the client

🏗️ Architecture

┌─────────────────────┐    IIOP/RMI     ┌─────────────────────┐
│   HelloWorldClient  │ ──────────────► │  HelloWorldServer   │
│                     │    Port 2814    │                     │
│  - Standalone JAR   │                 │  - WAR Application  │
│  - EJB Client       │                 │  - EJB Provider     │
│  - Liberty Client   │                 │  - Web Interface    │
└─────────────────────┘                 └─────────────────────┘
                                                │
                                                │ HTTP
                                                │ Port 9080
                                                ▼
                                        ┌─────────────────────┐
                                        │   Web Browser       │
                                        │                     │
                                        │  - Jakarta Faces    │
                                        │  - Interactive UI   │
                                        └─────────────────────┘

🚀 Features

HelloWorldServer

• EJB 4.0: Stateless session bean with remote interface
• Jakarta Faces 4.0: Modern web UI with AJAX support
• CDI 4.0: Dependency injection and managed beans
• Servlet 6.0: RESTful endpoints and test servlets
• OpenLiberty: Lightweight Jakarta EE runtime

HelloWorldClient

• Remote EJB Invocation: Demonstrates client-side EJB access
• JNDI Lookup: Traditional and modern EJB lookup patterns
• Error Handling: Comprehensive exception management
• Liberty Client: Integrated with OpenLiberty client runtime

HelloWorldClientEAR

• Enterprise Archive: Packages client as deployable EAR
• Liberty Configuration: Client-side Liberty server setup
• IIOP Configuration: Remote communication setup

🛠️ Prerequisites

• Java 21 or higher
• Apache Maven 3.6+
• OpenLiberty 25.0.0.12 (automatically downloaded by Maven)

🚀 Quick Start

1. Build the Projects

# Build the server
cd HelloWorldServer
mvn clean package

# Build the client EAR
cd HelloWorldClientEAR
mvn clean package

2. Start the Server

cd HelloWorldServer
mvn liberty:run

The server will start on:

• HTTP: http://localhost:9080
• IIOP: localhost:2814

3. Test the Web Interface

Open your browser and navigate to:

• Main UI: http://localhost:9080/HelloWorldServer/
• Servlet Test: http://localhost:9080/HelloWorldServer/test

4. Run the Standalone Client

In a new terminal:

5. Run the EAR Client

<wlp>/bin/client create HelloWorldClient
cd HelloWorldClientEAR
cp target/helloworldclient-1.0.ear <wlp>/usr/clients/HelloWorldClient/apps/
cp liberty/config/client.xml  <wlp>/usr/clients/HelloWorldClient/
<wlp>/bin/client run HelloWorldClient

🧪 Testing

Web Interface Tests

The Jakarta Faces interface (index.xhtml) provides:

• Automatic EJB Tests: Direct injection and JNDI lookup
• Interactive Greeting: Personalized message form
• Real-time Results: AJAX-powered updates

Servlet Tests

Access the servlet endpoints:

# Basic test
curl http://localhost:9080/HelloWorldServer/test

# Parameterized test  
curl "http://localhost:9080/HelloWorldServer/test?name=Jakarta"

Client Application Tests

The standalone client tests:

• EJB initialization and cleanup
• Basic sayHello() method
• Parameterized sayHello(String name) method
• Edge cases (null/empty parameters)

output should be similar to this when running the client:

Launching HelloWorldClient (WebSphere Application Server 25.0.0.12/wlp-1.0.108.cl251220251117-0302) on OpenJDK 64-Bit Server VM, version 21.0.9+10-LTS (en_US)
[AUDIT   ] CWWKE0907I: The client HelloWorldClient has been launched.
[INFO    ] TRAS0018I: The trace state has been changed. The new trace state is *=info:IIOP=all:Naming=all:com.ibm.example.*=all:org.apache.yoko.*=all:yoko.verbose.*=all.
[INFO    ] CWWKE0002I: The kernel started after 1.052 seconds
[INFO    ] CWWKF0007I: Feature update started.
[AUDIT   ] CWWKZ0058I: Monitoring dropins for applications.
[INFO    ] Aries Blueprint packages not available. So namespaces will not be registered
[INFO    ] WELD-000900: 5.1.1 (SP2)
[INFO    ] CXF message logging feature disabled
[INFO    ] CWWKZ0018I: Starting application HellowWorldClient.
[INFO    ] CWWKZ0136I: The HellowWorldClient application is using the archive file at the /Applications/IBM/wlp/usr/clients/HelloWorldClient/apps/helloworldclient-1.0.ear location.
[AUDIT   ] CWWKZ0001I: Application HellowWorldClient started in 0.263 seconds.
[AUDIT   ] CWWKF0034I: The client installed the following features: [beanValidation-3.0, cdi-4.0, expressionLanguage-5.0, jakartaeeClient-10.0, jdbc-4.2, jndi-1.0, jsonb-3.0, jsonp-2.1, mail-2.1, managedBeans-2.0, messagingClient-3.0, persistence-3.1, persistenceContainer-3.1, xmlBinding-4.0].
[INFO    ] CWWKF0008I: Feature update completed in 1.993 seconds.
[AUDIT   ] CWWKF0035I: The client HelloWorldClient is running.
Starting HelloWorld EJB Client...
Initializing EJB client...
Successfully looked up HelloWorld EJB

=== Testing sayHello() ===
Result: Hello World from Jakarta EE 10 EJB!

=== Testing sayHello(String name) ===
Result: Hello Liberty Client from Jakarta EE 10 EJB!

=== Testing sayHello with empty name ===
Result: Hello World from Jakarta EE 10 EJB!

=== Testing sayHello with null name ===
Result: Hello World from Jakarta EE 10 EJB!

=== All tests completed successfully! ===
EJB client cleanup completed.
[AUDIT   ] CWWKE1103I: Waiting for up to 30 seconds for the client to quiesce.
[INFO    ] CWWKE1104I: Client quiesce complete.
[AUDIT   ] CWWKZ0009I: The application HellowWorldClient has stopped successfully.
[AUDIT   ] CWWKE0908I: The client HelloWorldClient stopped after 6.079 seconds.