How do I throw Camunda business Error to out?

Question

My question about throwing a business error to out. For example, I have the some diagram and I start the process from method of Spring REST Controller. How I can catch "Error-CheckNoneAZNOperationIsExist" in test() method and throw it to out?

Camunda process diagram

@RestController
public class TestEndpoint{
    @Autowired
    ProcessEngine processEngine;

    @GetMapping(path = "account-close")
    public String test(){
        ProcessInstance processInstance = processEngine.getRuntimeService().startProcessInstanceByKey("account_close_flow");
        return "hi";
    }
}

Finally, I want to throw an exception to the consumer, when “Error End Event” is occurred, for example as JSON

{
    “errorMessage”: “CheckNoneAZNOperationIsExist”, 
    “errorCode”: 123 
}

Answer 1

Finally, I have found solution.

1) I added Error Code Variable (ex. globalError ) to all my boundary events

2) After execution of process I check historic variable instance (Camunda Java API)

@RestController
public class TestEndpoint{
    @Autowired
    ProcessEngine processEngine;

    @GetMapping(path = "x")
    public String test(){
        ProcessInstance processInstance = processEngine.getRuntimeService().startProcessInstanceByKey("account_close_flow");
        HistoricVariableInstanceEntity variable = (HistoricVariableInstanceEntity) processEngine.getHistoryService()
                .createHistoricVariableInstanceQuery()
                .processInstanceId(processInstance.getId())
                .variableName("globalError").singleResult();
        if(variable != null)
           throw new ResponseStatusException(HttpStatus.BAD_REQUEST, processInstance.getId() +" "+variable.getTextValue());

        return "hi";
    }
}

3) When error is occurred globalError is filled by Camunda Engine with "Error Name"

Camunda diagram example

Result of code above

{
    "timestamp": "2019-08-18T10:34:49.928+0000",
    "status": 400,
    "error": "Bad Request",
    "message": "ce72ca30-c1a3-11e9-bb0b-0a0027000005 ErrorUserIsFrozen",
    "path": "/x"
}