1. A machine with a working Docker installation
2. JDK 17 + an IDE for working with Java projects
3. Gradle >= 7.6 (or you can use the gradle-wrapper (./gradlew) from the repository)
4. A PostgreSQL client

To verify that the environment works, run:

gradle clean test --tests EnvironmentSetupTest --info

1. Python producer of quotes and trades /producer
   • Quotes are sent to the ticks topic
   • Trades are sent to the trades topic
   • Used in integration tests
   • The candidate does not need to dig into it
2. Java project /src
   • Unit and integration tests /src/test
     • EnvironmentSetupTest is an integration test that checks Kafka, the Python producers, and the Java code can work together.
   • models POJO classes for JSON deserialization

You can prepare for the live coding session in advance and do it as "homework":

1. Complete the following classes com.exness.livecoding.models.Tick, com.exness.livecoding.models.Trade for JSON deserialization, so that these tests pass:

   gradle test --tests com.exness.livecoding.models.TickTest
   gradle test --tests com.exness.livecoding.models.TradeTest

   • JSON examples can be found in the tests, or seen in the logs when running the EnvironmentSetupTest test
   • The class must implement getters for all fields
2. Write a Kafka consumer that receives and deserializes JSON into the POJO objects implemented in step 1

Bring up Kafka, PostgreSQL and the Python producers:

docker-compose up -d

Services exposed on the host:

• Kafka broker — localhost:9092
• PostgreSQL — localhost:5432, db livecoding, user postgres, password mysecretpassword

The application reads these settings from application.yml (each value can be overridden via environment variables, e.g. KAFKA_BOOTSTRAP_SERVERS, SPRING_DATASOURCE_URL). PostgreSQL is initialized with the schema from init.sql (ticks, trades, trades_enriched tables).

Could not find a valid Docker environment when running the Testcontainers tests (even though Docker is up). Recent Docker Desktop defaults to a newer Docker API version that the bundled Testcontainers / docker-java client can fail to negotiate.

Fix: pin a minimum API version in Docker Desktop → Settings → Docker Engine, add "min-api-version": "1.24" to the JSON config, then Apply & Restart:

{
  "min-api-version": "1.24"
}