Cannot resolve ResponseEntity in SpringMVC using JpaRepository
<p>This is my Controller:</p>

<pre><code>package com.hodor.booking.controller;

import com.hodor.booking.jpa.domain.Vehicle;
import com.hodor.booking.service.VehicleService;
import com.wordnik.swagger.annotations.Api;
import org.apache.commons.lang.time.DateUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.Date;
import java.util.List;

@RestController
@RequestMapping("/api/v1/vehicles")
@Api(value = "vehicles", description = "Vehicle resource endpoint")

public class VehicleController {

    private static final Logger log = LoggerFactory.getLogger(VehicleController.class);

    @Autowired
    private VehicleService vehicleService;

    @RequestMapping(method = RequestMethod.GET)
    public List&lt;Vehicle&gt; index() {
        log.debug("Getting all vehicles");
        return vehicleService.findAll();
    }

    @RequestMapping(value="/save", method=RequestMethod.POST, consumes="application/json")

    @ResponseBody
    public Vehicle setVehicle(@RequestBody Vehicle vehicle) {
        log.debug("Inserting vehicle");

        if (vehicle.getLicensePlate() == null){
            return new ResponseEntity&lt;Void&gt;(HttpStatus.CONFLICT);
        }

        return vehicleService.saveVehicle(vehicle);
    }
}
</code></pre>

<p>What I want to achieve in above If-Guard is that, in case the vehicle Object does not have the LicensePlate Member, send back an according HTTP Status Header CONFLICT or something. </p>

<p>I am coming from a Node and Express background and I am used to set my header, send the response and be done with it. However in this case (JPA) it does not seem to work. Any ideas?</p>