Could not parse external task

[Boris_Gregor]

Hi, I have problem to simply fetchAndLock external task via externalTaskClient. When I subscribe to an existing topic where I have one task waiting, I receive

> Caused by: com.fasterxml.jackson.core.JsonParseException: Unexpected character ('<' (code 60)): expected a valid value (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
>  at [Source: (org.apache.hc.core5.http.io.EofSensorInputStream); line: 1, column: 2]

When I debug camunda internal classes I found response contains:
404 Not Found HTTP/1.1

I used example code from git

ExternalTaskClient client = ExternalTaskClient.create()
            .baseUrl("http://localhost:8080/engine-rest")
            .asyncResponseTimeout(1000)
            .customizeHttpClient(httpClientBuilder -> {
                httpClientBuilder.setDefaultRequestConfig(RequestConfig.custom()
                    .setResponseTimeout(Timeout.ofSeconds(15))
                    .build());
            })
            .build();

        // subscribe to the topic
        client.subscribe("my-job")
            .handler((externalTask, externalTaskService) -> {

                System.out.println("The External Task " + externalTask.getId() +
                    " has been completed!");

            }).open();

When I tried to do POST via postman I succeeded:

POST http://localhost:8080/engine-rest/external-task/fetchAndLock
200
12 ms
POST /engine-rest/external-task/fetchAndLock HTTP/1.1
Content-Type: application/json
Cache-Control: no-cache
Postman-Token: 90d59a92-416e-4bba-a2e5-cb9092991c2a
Host: localhost:8080
Content-Length: 140
 
{
"maxTasks": "10",
"topics": [
{
"topicName": "my-job",
"lockDuration": "10000"
}
]
}
 
HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 744
Date: Wed, 28 Aug 2024 08:06:38 GMT
 
[{"activityId":"Activity_0uha6vd","activityInstanceId":"Activity_0uha6vd:bd865718-646f-11ef-87ee-6e671798553f","errorMessage":null,"errorDetails":null,"executionId":"bd865717-646f-11ef-87ee-6e671798553f","id":"bd86a539-646f-11ef-87ee-6e671798553f","lockExpirationTime":"2024-08-28T10:06:48.933+0200","createTime":"2024-08-27T14:27:35.563+0200","processDefinitionId":"Process_cam7_quarkus_intg:2:bbdb6634-646f-11ef-87ee-6e671798553f","processDefinitionKey":"Process_cam7_quarkus_intg","processDefinitionVersionTag":null,"processInstanceId":"bd8608f5-646f-11ef-87ee-6e671798553f","retries":null,"suspended":false,"workerId":"quarkusino","topicName":"my-job","tenantId":null,"variables":{},"priority":0,"businessKey":"0","extensionProperties":{}}]

I use clean maven project containing just these dependencies:

<dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.camunda.bpm</groupId>
      <artifactId>camunda-external-task-client</artifactId>
      <version>7.21.0</version>
    </dependency>
    <dependency>
      <groupId>com.sun.xml.bind</groupId>
      <artifactId>jaxb-impl</artifactId>
      <version>4.0.5</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>2.0.9</version>
    </dependency>

    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-simple</artifactId>
      <version>2.0.9</version>
      <scope>runtime</scope>
    </dependency>
  </dependencies>

Camunda runs as standalone app version 7.21.0 started via start.sh. Everything runs on Macbook M2 with jakarta 17 Temurin. Any ideas what could help?