Hystrix sees List as incompatible return type in - hystrix

Question

I have the following Hystrix fallback
public List<Data> getDataFallback(String id, LocalDate startDate, LocalDate endDate, Throwable t) {
log.warn("Could not get data");
throw new DataException(ErrorMessage.builder()
.code(COULD_NOT_GET_DATA.name())
.internalMessage(t.getMessage())
.build());
}
It is attached to the following method
#Override
#HystrixCommand(fallbackMethod = "getDataFallback")
public List<Data> getData(String id, LocalDate startDate, LocalDate endDate) {
return repository.find(id, startDate, endDate);
}
When running JUnit tests, and presumably also when running the service, I get the following error when running the getData-method
com.netflix.hystrix.contrib.javanica.exception.FallbackDefinitionException: Incompatible return types.
Command method: public java.util.List package.class.getData(java.lang.String,java.time.LocalDate,java.time.LocalDate);
Fallback method: public java.util.List package.class.getDataFallback(java.lang.String,java.time.LocalDate,java.time.LocalDate,java.lang.Throwable);
Hint: Different size of types variables.
Command type literals size = 2: [java.util.List<package.Data>, class package.Data]
Fallback type literals size = 1: [interface java.util.List]
If I wrap the list in a wrapper object, the exact same configuration works without a hitch. What gives?

Answer 1

Method Return type
and Parameter should be same
only one extra argument (Throwable throwable)
#GetMapping("/msg")
#HystrixCommand(fallbackMethod="fallBackGetUsers")
public String localMessage() {
return userServices.localMassage();
}
/*
* fallBack method parameter should be same and One Extra parameter will be
* there only and Return type also same
*/
public String fallBackGetUsers(Throwable throwable) {
return "fallback";
}