Up to and including part 5 completed

src/main/java/io/zipcoder/tc_spring_poll_application/exception/RestExceptionHandler.java

 
 import io.zipcoder.tc_spring_poll_application.error.ErrorDetail;
 import io.zipcoder.tc_spring_poll_application.error.ValidationError;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.MessageSource;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.validation.FieldError;
 import org.springframework.web.bind.MethodArgumentNotValidException;
-import org.springframework.web.bind.annotation.ControllerAdvice;
-import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.*;
 import sun.tools.tree.FieldExpression;
 
 import javax.servlet.http.HttpServletRequest;
 @ControllerAdvice
 public class RestExceptionHandler {
 
+    @Autowired
+    private MessageSource messageSource;
+
     //    @ExceptionHandler(ResourceNotFoundException.class)
 //    public ResponseEntity<?> handleResourceNotFoundException(ResourceNotFoundException rnfe, HttpServletRequest request) {
 //        ErrorDetail errorDetail = new ErrorDetail();
 //        return  new ResponseEntity<>(errorDetail, null, HttpStatus.NOT_FOUND);
 //        }
     @ExceptionHandler(MethodArgumentNotValidException.class)
-    public ResponseEntity<?>
-    handleValidationError(MethodArgumentNotValidException manve, HttpServletRequest request) {
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    public @ResponseBody ErrorDetail handleValidationError(MethodArgumentNotValidException
+        manve, HttpServletRequest request) {
 
         ErrorDetail errorDetail = new ErrorDetail();
         // Populate errorDetail instance
             List<ValidationError> validationErrorList = errorDetail.getErrors().get(fe.getField());
             if (validationErrorList == null) {
                 validationErrorList = new ArrayList<ValidationError>();
-                errorDetail.getErrors().put(fe.getField(), validationErrorList);
+                errorDetail.getErrors().put(fe.getField(),
+                    validationErrorList);
             }
             ValidationError validationError = new ValidationError();
             validationError.setCode(fe.getCode());
-            validationError.setMessage(fe.getDefaultMessage());
+            validationError.setMessage(messageSource.getMessage(fe,null));
             validationErrorList.add(validationError);
         }
-        return new ResponseEntity<>(errorDetail, null, HttpStatus.BAD_REQUEST);
+        return errorDetail;
 
     }
     /** handleResourceNotFoundException method removed **/

src/resources/messages.properties

+NotEmpty.poll.question=Question is a required field
+Size.poll.options=Options must be greater than {2} and less than {1}