Java serialization format is prohibited when completing the external task with external task client. Same exception occurs in Camunda engine and client service.
2020-11-11 23:37:00.670 ERROR 36828 — [criptionManager] org.camunda.bpm.client : TASK/CLIENT-03004 Exception on external task service method invocation for topic ‘updateOperation’:
org.camunda.bpm.client.exception.NotResumedException: TASK/CLIENT-01009 Exception while completing the external task: The corresponding process instance could not be resumed. Reason: {“type”:“ProcessEngineException”,“message”:“ENGINE-17007 Cannot set variable with name reconRequest. Java serialization format is prohibited”}
at org.camunda.bpm.client.impl.ExternalTaskClientLogger.externalTaskServiceException(ExternalTaskClientLogger.java:124)
at org.camunda.bpm.client.task.impl.ExternalTaskServiceImpl.complete(ExternalTaskServiceImpl.java:68)
at org.camunda.bpm.client.task.impl.ExternalTaskServiceImpl.complete(ExternalTaskServiceImpl.java:61)
at org.camunda.bpm.client.task.impl.ExternalTaskServiceImpl.complete(ExternalTaskServiceImpl.java:56)
at lk.dialog.crm.service.impl.ExternalTaskServiceImpl.lambda$1(ExternalTaskServiceImpl.java:139)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.handleExternalTask(TopicSubscriptionManager.java:152)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.lambda$acquire$0(TopicSubscriptionManager.java:108)
at java.util.Arrays$ArrayList.forEach(Arrays.java:3880)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.acquire(TopicSubscriptionManager.java:103)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.run(TopicSubscriptionManager.java:87)
at java.lang.Thread.run(Thread.java:748)