Camunda 8 - Develop Your First Job Worker (Java) - Lab

Lab project for the Camunda 8 - Develop your first job worker (Java) course on Camunda Academy.

This project introduces the end-to-end basics of building a Camunda 8 Java worker:

• connecting a Java application to Camunda 8 SaaS
• deploying and executing a BPMN process with a service task
• implementing a job worker to complete work and return output variables

Difficulty: Foundation | Time: ~2h | Platform: Camunda 8.9+

What you will learn

• Create and run a Java application that connects to Camunda 8
• Start a process instance from code
• Implement a job worker (chargeCreditCard) using the Camunda Java client
• Read process variables in the worker and complete the job with output variables
• Understand the relationship between BPMN task type and worker job type

Overview

The process definition paymentProcess contains one service task:

• Charge Credit Card (chargeCreditCard) handled by CreditCardServiceHandler

High-level flow:

1. The app creates a process instance with payment variables.
2. A worker polls for chargeCreditCard jobs.
3. The handler calls CreditCardService and returns a confirmation output variable.

Prerequisites

Knowledge

• Awareness of Camunda
• Competent with BPMN
• Competent with Java

Recommended preparatory material:

• Camunda - Overview

Tools & Access

• Java 21+
• Maven 3.x
• IDE (Eclipse, IntelliJ, or VS Code)
• Camunda 8 SaaS account with:
  • a running cluster
  • OAuth client credentials

Configuration

This lab uses constants in src/main/java/com/camunda/academy/PaymentApplication.java for Camunda connection settings.

Update the following placeholders before running:

• CAMUNDA_REST_ADDRESS (for example: https://[REGION].zeebe.camunda.io/[CLUSTER-ID])
• CAMUNDA_GRPC_ADDRESS (for example: https://[CLUSTER-ID].[REGION].zeebe.camunda.io:443)
• CAMUNDA_CLIENT_ID
• CAMUNDA_CLIENT_SECRET

Defaults already provided in code:

• CAMUNDA_AUTHORIZATION_SERVER_URL = https://login.cloud.camunda.io/oauth/token
• CAMUNDA_TOKEN_AUDIENCE = zeebe.camunda.io

Build

mvn clean package

Run

Before running, deploy src/main/resources/paymentProcess.bpmn to your Camunda 8 cluster (Desktop Modeler or Web Modeler).

Then start the application:

mvn exec:java -Dexec.mainClass="com.camunda.academy.PaymentApplication"

When running successfully, the app:

1. creates one paymentProcess instance
2. starts a worker for job type chargeCreditCard
3. processes the payment task and completes the job with a confirmation variable

Project Structure

src/main/java/com/camunda/academy/
├── PaymentApplication.java                  # Entry point: client setup, instance creation, worker startup
├── handler/
│   └── CreditCardServiceHandler.java        # Job handler for chargeCreditCard
└── service/
    └── CreditCardService.java               # Simulated payment logic

src/main/resources/
├── paymentProcess.png                       # Process diagram used in this README
└── paymentProcess.bpmn                      # BPMN process definition

Dependencies

• io.camunda:camunda-client-java (8.9.1) - Camunda 8 Java client
• org.slf4j:slf4j-simple (2.0.16) - logging
• junit:junit (4.13.2) - test dependency

License

This project is licensed under the Apache-2.0 License. See LICENSE.