now finish 2nd practical for real.

src/main/java/ua/com/dxrkness/client/ApplicationClient.java

@@ -5,6 +5,8 @@ import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
 import org.apache.http.util.EntityUtils;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
 import tools.jackson.databind.ObjectMapper;
 import tools.jackson.dataformat.xml.XmlMapper;
 import ua.com.dxrkness.model.Freight;
@@ -29,7 +31,7 @@ public class ApplicationClient {
             testInterServiceValidation(client);
 
         } catch (Exception e) {
-            System.err.println("error: " + e.getMessage());
+            System.out.println("error: " + e.getMessage());
             e.printStackTrace();
         }
     }
@@ -53,18 +55,12 @@ public class ApplicationClient {
         execute(client, new HttpGet(BASE_URL + "/vehicles/999"), "GET vehicle by ID=999 (not found)");
 
         Vehicle updateVehicle = new Vehicle(1, "Volvo", "FH16", "BB5678CC", 2024, 20000, Vehicle.Status.MAINTENANCE);
-        String updateJson = jsonMapper.writeValueAsString(updateVehicle);
+        var vehiclePut = createHttpRequest(updateVehicle, "/vehicles/0", HttpMethod.PUT);
-        HttpPut put = new HttpPut(BASE_URL + "/vehicles/0");
+        execute(client, vehiclePut, "PUT update vehicle ID=0");
-        put.setEntity(new StringEntity(updateJson, "UTF-8"));
-        put.setHeader("Content-Type", "application/json");
-        execute(client, put, "PUT update vehicle ID=0");
 
         Vehicle patchVehicle = new Vehicle(1, "Volvo", "FH16", "BB5678CC", 2024, 20000, Vehicle.Status.IN_TRANSIT);
-        String patchJson = jsonMapper.writeValueAsString(patchVehicle);
+        var vehiclePatch = createHttpRequest(patchVehicle, "/vehicles/0", HttpMethod.PATCH);
-        HttpPatch patch = new HttpPatch(BASE_URL + "/vehicles/0");
+        execute(client, vehiclePatch, "PATCH update vehicle ID=0");
-        patch.setEntity(new StringEntity(patchJson, "UTF-8"));
-        patch.setHeader("Content-Type", "application/json");
-        execute(client, patch, "PATCH update vehicle ID=0");
 
         execute(client, new HttpDelete(BASE_URL + "/vehicles/999"), "DELETE vehicle ID=999 (not found)");
 
@@ -78,28 +74,19 @@ public class ApplicationClient {
 
         Freight.Dimensions dims = new Freight.Dimensions(120, 100, 200);
         Freight newFreight = new Freight(0, "Electronics", "Laptops and monitors", 500, dims, Freight.Status.PENDING);
-        String freightJson = jsonMapper.writeValueAsString(newFreight);
+        var freightPost = createHttpRequest(newFreight, "/freights", HttpMethod.POST);
-        HttpPost post = new HttpPost(BASE_URL + "/freights");
+        execute(client, freightPost, "POST new freight");
-        post.setEntity(new StringEntity(freightJson, "UTF-8"));
-        post.setHeader("Content-Type", "application/json");
-        execute(client, post, "POST new freight");
 
-        execute(client, new HttpGet(BASE_URL + "/freights/0"), "GET freight by ID=1");
+        execute(client, new HttpGet(BASE_URL + "/freights/0"), "GET freight by ID=0");
         execute(client, new HttpGet(BASE_URL + "/freights/999"), "GET freight by ID=999 (not found)");
 
         Freight updateFreight = new Freight(1, "Furniture", "Office desks", 800, dims, Freight.Status.IN_TRANSIT);
-        String updateJson = jsonMapper.writeValueAsString(updateFreight);
+        var freightPut = createHttpRequest(updateFreight, "/freights/0", HttpMethod.PUT);
-        HttpPut put = new HttpPut(BASE_URL + "/freights/0");
+        execute(client, freightPut, "PUT update freight ID=0");
-        put.setEntity(new StringEntity(updateJson, "UTF-8"));
-        put.setHeader("Content-Type", "application/json");
-        execute(client, put, "PUT update freight ID=1");
 
         Freight patchFreight = new Freight(1, "Furniture", "Office desks", 800, dims, Freight.Status.DELIVERED);
-        String patchJson = jsonMapper.writeValueAsString(patchFreight);
+        var freightPatch = createHttpRequest(patchFreight, "/freights/0", HttpMethod.PATCH);
-        HttpPatch patch = new HttpPatch(BASE_URL + "/freights/0");
+        execute(client, freightPatch, "PATCH update freight ID=0");
-        patch.setEntity(new StringEntity(patchJson, "UTF-8"));
-        patch.setHeader("Content-Type", "application/json");
-        execute(client, patch, "PATCH update freight ID=1");
 
         execute(client, new HttpDelete(BASE_URL + "/freights/999"), "DELETE freight ID=999 (not found)");
 
@@ -109,34 +96,22 @@ public class ApplicationClient {
     private static void testRoutes(CloseableHttpClient client) throws Exception {
         System.out.println("--- ROUTES ---");
 
+        Route newRoute = new Route(0, 0, List.of(0L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
+        var routePost = createHttpRequest(newRoute, "/routes", HttpMethod.POST);
+        execute(client, routePost, "POST new route");
+
         execute(client, new HttpGet(BASE_URL + "/routes"), "GET all routes");
 
-        execute(client, new HttpGet(BASE_URL + "/routes?vehicleId=0"), "GET routes by vehicleId=1");
-        execute(client, new HttpGet(BASE_URL + "/routes?freightId=0"), "GET routes by freightId=1");
-
-        Route newRoute = new Route(0, 0, List.of(0L, 1L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
-        String routeJson = jsonMapper.writeValueAsString(newRoute);
-        HttpPost post = new HttpPost(BASE_URL + "/routes");
-        post.setEntity(new StringEntity(routeJson, "UTF-8"));
-        post.setHeader("Content-Type", "application/json");
-        execute(client, post, "POST new route");
-
         execute(client, new HttpGet(BASE_URL + "/routes/0"), "GET route by ID=0");
         execute(client, new HttpGet(BASE_URL + "/routes/999"), "GET route by ID=999 (not found)");
 
-        Route updateRoute = new Route(1, 1, List.of(1L), "Kyiv", "Odesa", 480.0, 7.0, Route.Status.IN_PROGRESS);
+        Route updateRoute = new Route(0, 0, List.of(0L), "Kyiv", "Odesa", 480.0, 7.0, Route.Status.IN_PROGRESS);
-        String updateJson = jsonMapper.writeValueAsString(updateRoute);
+        var routePut = createHttpRequest(updateRoute, "/routes/0", HttpMethod.PUT);
-        HttpPut put = new HttpPut(BASE_URL + "/routes/0");
+        execute(client, routePut, "PUT update route ID=0");
-        put.setEntity(new StringEntity(updateJson, "UTF-8"));
-        put.setHeader("Content-Type", "application/json");
-        execute(client, put, "PUT update route ID=0");
 
-        Route patchRoute = new Route(1, 1, List.of(1L), "Kyiv", "Odesa", 480.0, 7.0, Route.Status.COMPLETED);
+        Route patchRoute = new Route(0, 0, List.of(0L), "Kyiv", "Odesa", 480.0, 7.0, Route.Status.COMPLETED);
-        String patchJson = jsonMapper.writeValueAsString(patchRoute);
+        var routePatch = createHttpRequest(patchRoute, "/routes/0", HttpMethod.PATCH);
-        HttpPatch patch = new HttpPatch(BASE_URL + "/routes/0");
+        execute(client, routePatch, "PATCH update route ID=0");
-        patch.setEntity(new StringEntity(patchJson, "UTF-8"));
-        patch.setHeader("Content-Type", "application/json");
-        execute(client, patch, "PATCH update route ID=0");
 
         execute(client, new HttpDelete(BASE_URL + "/routes/999"), "DELETE route ID=999 (not found)");
 
@@ -146,9 +121,8 @@ public class ApplicationClient {
     private static void testSubResources(CloseableHttpClient client) throws Exception {
         System.out.println("--- SUB-RESOURCES ---");
 
-        execute(client, new HttpGet(BASE_URL + "/vehicles/1/routes"), "GET routes for vehicle ID=1 (sub-resource)");
+        execute(client, new HttpGet(BASE_URL + "/routes/0/freights"), "GET freights for route ID=0 (sub-resource)");
-        execute(client, new HttpGet(BASE_URL + "/routes/1/freights"), "GET freights for route ID=1 (sub-resource)");
+        execute(client, new HttpGet(BASE_URL + "/routes/0/vehicle"), "GET vehicle for route ID=0 (sub-resource)");
-        execute(client, new HttpGet(BASE_URL + "/vehicles/999/routes"), "GET routes for vehicle ID=999 (not found)");
 
         System.out.println();
     }
@@ -178,48 +152,52 @@ public class ApplicationClient {
 
     private static void testInterServiceValidation(CloseableHttpClient client) throws Exception {
         System.out.println("--- INTER-SERVICE COMMUNICATION & VALIDATION ---");
-        System.out.println("This section demonstrates inter-service communication where:");
-        System.out.println("- RouteService validates that vehicle exists by calling VehicleService");
-        System.out.println("- RouteService validates that all freights exist by calling FreightService");
-        System.out.println("- Services communicate using DTOs (not direct entities)");
-        System.out.println();
 
         // Test 1: Create route with valid references (should succeed)
         System.out.println("[INTER-SERVICE TEST 1] Creating route with valid vehicle and freight references:");
-        Route validRoute = new Route(0, 1, List.of(1L, 2L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
+        Route validRoute = new Route(0, 0, List.of(0L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
-        String validRouteJson = jsonMapper.writeValueAsString(validRoute);
+        var validRoutePost = createHttpRequest(validRoute, "/routes", HttpMethod.POST);
-        HttpPost validRoutePost = new HttpPost(BASE_URL + "/routes");
-        validRoutePost.setEntity(new StringEntity(validRouteJson, "UTF-8"));
-        validRoutePost.setHeader("Content-Type", "application/json");
         execute(client, validRoutePost, "POST route with valid vehicle and freights (should succeed)");
 
         // Test 2: Create route with invalid vehicle (should fail with 404)
         System.out.println("[INTER-SERVICE TEST 2] Creating route with INVALID vehicle ID:");
         Route invalidVehicleRoute = new Route(0, -999, List.of(1L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
-        String invalidVehicleJson = jsonMapper.writeValueAsString(invalidVehicleRoute);
+        var invalidRoutePost = createHttpRequest(invalidVehicleRoute, "/routes", HttpMethod.POST);
-        HttpPost invalidVehiclePost = new HttpPost(BASE_URL + "/routes");
+        execute(client, invalidRoutePost, "POST route with invalid vehicle ID, should result in 404");
-        invalidVehiclePost.setEntity(new StringEntity(invalidVehicleJson, "UTF-8"));
-        invalidVehiclePost.setHeader("Content-Type", "application/json");
-        execute(client, invalidVehiclePost, 
-                "POST route with invalid vehicle ID (inter-service validation fails → 404 Not Found)");
 
         // Test 3: Create route with invalid freight (should fail with 404)
         System.out.println("[INTER-SERVICE TEST 3] Creating route with INVALID freight ID:");
-        Route invalidFreightRoute = new Route(0, 1, List.of(-999L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
+        Route invalidFreightRoute = new Route(0, 0, List.of(-999L), "Kyiv", "Lviv", 540.0, 8.5, Route.Status.PLANNED);
-        String invalidFreightJson = jsonMapper.writeValueAsString(invalidFreightRoute);
+        var invalidFreightPost = createHttpRequest(invalidFreightRoute, "/routes", HttpMethod.POST);
-        HttpPost invalidFreightPost = new HttpPost(BASE_URL + "/routes");
+        execute(client, invalidFreightPost, "POST route with invalid freight ID, should result in 404");
-        invalidFreightPost.setEntity(new StringEntity(invalidFreightJson, "UTF-8"));
+    }
-        invalidFreightPost.setHeader("Content-Type", "application/json");
-        execute(client, invalidFreightPost, 
-                "POST route with invalid freight ID (inter-service validation fails → 404 Not Found)");
 
-        System.out.println();
+    private static <T> HttpUriRequest createHttpRequest(T entity, String path, HttpMethod method) {
-        System.out.println("Summary: The above tests demonstrate that:");
+        String entityJson = jsonMapper.writeValueAsString(entity);
-        System.out.println("✓ RouteService uses inter-service calls to VehicleService and FreightService");
+        HttpEntityEnclosingRequestBase req;
-        System.out.println("✓ DTOs are used for data transfer across service boundaries");
+
-        System.out.println("✓ Validation happens before route is created");
+        if (method == HttpMethod.GET) {
-        System.out.println("✓ Proper error codes (404) are returned for validation failures");
+            return new HttpGet(BASE_URL + path);
-        System.out.println();
+        } else if (method == HttpMethod.POST) {
+            req = new HttpPost(BASE_URL + path);
+            req.setEntity(new StringEntity(entityJson, "UTF-8"));
+            req.setHeader("Content-Type", "application/json");
+            return req;
+        } else if (method == HttpMethod.PUT) {
+            req = new HttpPut(BASE_URL + path);
+            req.setEntity(new StringEntity(entityJson, "UTF-8"));
+            req.setHeader("Content-Type", "application/json");
+            return req;
+        } else if (method == HttpMethod.PATCH) {
+            req = new HttpPatch(BASE_URL + path);
+            req.setEntity(new StringEntity(entityJson, "UTF-8"));
+            req.setHeader("Content-Type", "application/json");
+            return req;
+        } else if (method == HttpMethod.DELETE) {
+            return new HttpDelete(BASE_URL + path);
+        } else {
+            throw new IllegalArgumentException("method is invalid");
+        }
     }
 
     private static String execute(CloseableHttpClient client, HttpUriRequest request, String description) {
@@ -234,14 +212,14 @@ public class ApplicationClient {
                 System.out.println("Response: " + body);
             }
 
-            if (statusCode >= 400) {
+            if (HttpStatus.valueOf(statusCode).isError()) {
-                System.err.println("ERROR: Request failed with status " + statusCode);
+                System.out.println("ERROR: Request failed with status " + statusCode);
             }
 
             System.out.println();
             return body;
         } catch (Exception e) {
-            System.err.println("EXCEPTION: " + e.getMessage());
+            System.out.println("EXCEPTION: " + e.getMessage());
             e.printStackTrace();
             System.out.println();
             return null;

src/main/java/ua/com/dxrkness/controller/FreightController.java

@@ -2,11 +2,8 @@ package ua.com.dxrkness.controller;
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
-import io.swagger.v3.oas.annotations.media.Content;
-import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
-import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.Nullable;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
@@ -23,7 +20,6 @@ import java.util.List;
         consumes = {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE}
 )
 @Tag(name = "Freight", description = "Freights management")
-@NullMarked
 public class FreightController {
     private final FreightService service;
 
@@ -37,11 +33,7 @@ public class FreightController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Successfully retrieved list of freights (may be empty!)",
+            description = "Successfully retrieved list of freights (may be empty!)"
-            content = @Content(
-                    mediaType = MediaType.APPLICATION_JSON_VALUE,
-                    schema = @Schema(implementation = Freight.class)
-            )
     )
     @GetMapping(consumes = MediaType.ALL_VALUE)
     public List<Freight> getAll(
@@ -59,42 +51,32 @@ public class FreightController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Successfully retrieved freight",
+            description = "Successfully retrieved freight"
-            content = @Content(
-                    mediaType = MediaType.APPLICATION_JSON_VALUE,
-                    schema = @Schema(implementation = Freight.class)
-            )
     )
     @ApiResponse(
             responseCode = "404",
             description = "Freight not found"
     )
     @GetMapping(value = "/{id}", consumes = MediaType.ALL_VALUE)
-    public ResponseEntity<Freight> getById(@PathVariable("id") long id) {
+    public Freight getById(@PathVariable("id") long id) {
-        return ResponseEntity.ok(service.getById(id));
+        return service.getById(id);
     }
 
     @Operation(
             summary = "Create a new freight",
-            description = "Adds a new freight. The FreightService can validate freight properties " +
+            description = "Adds a new freight"
-                    "against vehicle capacity through inter-service communication with VehicleService. " +
-                    "This demonstrates the service layer design pattern for business logic validation."
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Freight successfully created",
+            description = "Freight successfully created"
-            content = @Content(
-                    mediaType = MediaType.APPLICATION_JSON_VALUE,
-                    schema = @Schema(implementation = Freight.class)
-            )
     )
     @ApiResponse(
             responseCode = "400",
-            description = "Invalid freight data (e.g., weight exceeds vehicle capacity) - inter-service validation failure"
+            description = "Invalid freight data (e.g., weight exceeds vehicle capacity)"
     )
     @PostMapping
-    public ResponseEntity<Freight> add(@RequestBody Freight newFreight) {
+    public Freight add(@RequestBody Freight newFreight) {
-        return ResponseEntity.ok(service.add(newFreight));
+        return service.add(newFreight);
     }
 
     @Operation(
@@ -103,19 +85,15 @@ public class FreightController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Freight successfully updated",
+            description = "Freight successfully updated"
-            content = @Content(
-                    mediaType = MediaType.APPLICATION_JSON_VALUE,
-                    schema = @Schema(implementation = Freight.class)
-            )
     )
     @ApiResponse(
             responseCode = "400",
             description = "Invalid input"
     )
     @PutMapping("/{id}")
-    public ResponseEntity<Freight> update(@PathVariable("id") long id, @RequestBody Freight newFreight) {
+    public Freight update(@PathVariable("id") long id, @RequestBody Freight newFreight) {
-        return ResponseEntity.ok(service.update(id, newFreight));
+        return service.update(id, newFreight);
     }
 
     @Operation(
@@ -124,19 +102,15 @@ public class FreightController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Freight successfully updated",
+            description = "Freight successfully updated"
-            content = @Content(
-                    mediaType = MediaType.APPLICATION_JSON_VALUE,
-                    schema = @Schema(implementation = Freight.class)
-            )
     )
     @ApiResponse(
             responseCode = "400",
             description = "Invalid input"
     )
     @PatchMapping("/{id}")
-    public ResponseEntity<Freight> updatePatch(@PathVariable("id") long id, @RequestBody Freight newFreight) {
+    public Freight updatePatch(@PathVariable("id") long id, @RequestBody Freight newFreight) {
-        return ResponseEntity.ok(service.update(id, newFreight));
+        return service.update(id, newFreight);
     }
 
     @Operation(
@@ -145,18 +119,14 @@ public class FreightController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Freight successfully deleted",
+            description = "Freight successfully deleted"
-            content = @Content(
-                    mediaType = MediaType.APPLICATION_JSON_VALUE,
-                    schema = @Schema(implementation = Freight.class)
-            )
     )
     @ApiResponse(
             responseCode = "404",
             description = "Freight not found"
     )
     @DeleteMapping(value = "/{id}", consumes = MediaType.ALL_VALUE)
-    public ResponseEntity<Freight> delete(@PathVariable("id") long id) {
+    public Freight delete(@PathVariable("id") long id) {
-        return ResponseEntity.ofNullable(service.delete(id));
+        return service.delete(id);
     }
 }

src/main/java/ua/com/dxrkness/controller/GlobalExceptionHandler.java

@@ -19,7 +19,7 @@ public class GlobalExceptionHandler {
             FreightNotFoundException.class,
             RouteNotFoundException.class
     })
-    public ErrorResponse handleVehicleNotFoundException(VehicleNotFoundException ex) {
+    public ErrorResponse handleVehicleNotFoundException(Exception ex) {
         return constructExceptionBody(HttpStatus.NOT_FOUND, ex);
     }
 

src/main/java/ua/com/dxrkness/controller/RouteController.java

@@ -2,18 +2,20 @@ package ua.com.dxrkness.controller;
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
-import io.swagger.v3.oas.annotations.media.Content;
-import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.Nullable;
 import org.springframework.http.MediaType;
-import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
+import ua.com.dxrkness.model.Freight;
 import ua.com.dxrkness.model.Route;
+import ua.com.dxrkness.model.Vehicle;
+import ua.com.dxrkness.service.FreightService;
 import ua.com.dxrkness.service.RouteService;
+import ua.com.dxrkness.service.VehicleService;
 
+import java.util.ArrayList;
 import java.util.List;
 
 @RestController
@@ -25,10 +27,16 @@ import java.util.List;
 @Tag(name = "Route", description = "Routes management")
 @NullMarked
 public class RouteController {
-    private final RouteService service;
+    private final RouteService routeService;
+    private final VehicleService vehicleService;
+    private final FreightService freightService;
 
-    public RouteController(RouteService service) {
+    public RouteController(RouteService routeService,
-        this.service = service;
+                           VehicleService vehicleService,
+                           FreightService freightService) {
+        this.routeService = routeService;
+        this.vehicleService = vehicleService;
+        this.freightService = freightService;
     }
 
     @Operation(
@@ -37,10 +45,7 @@ public class RouteController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Successfully retrieved routes",
+            description = "Successfully retrieved routes"
-            content = @Content(
-                    schema = @Schema(implementation = Route.class)
-            )
     )
     @GetMapping(consumes = MediaType.ALL_VALUE)
     public List<Route> getAll(
@@ -51,111 +56,19 @@ public class RouteController {
             @Parameter(description = "Filter routes by status (PLANNED, IN_PROGRESS, COMPLETED, CANCELLED)")
             @RequestParam(name = "status", required = false) Route.@Nullable Status status) {
         if (status != null) {
-            return service.getByStatus(status);
+            return routeService.getByStatus(status);
         }
         if (vehicleId != null) {
-            return service.getByVehicleId(vehicleId);
+            return routeService.getByVehicleId(vehicleId);
         }
         if (freightId != null) {
-            var route = service.getByFreightId(freightId);
+            var route = routeService.getByFreightId(freightId);
             if (route == null) {
                 return List.of();
             }
             return List.of(route);
         }
-        return service.getAll();
+        return routeService.getAll();
-    }
-
-    @Operation(
-            summary = "Create new route",
-            description = "Add new route"
-    )
-    @ApiResponse(
-            responseCode = "200",
-            description = "Route successfully created",
-            content = @Content(
-                    schema = @Schema(implementation = Route.class)
-            )
-    )
-    @ApiResponse(
-            responseCode = "400",
-            description = "Invalid route data: vehicle or freight not found"
-    )
-    @ApiResponse(
-            responseCode = "404",
-            description = "Referenced vehicle or freight not found (inter-service validation failure)"
-    )
-    @PostMapping
-    public ResponseEntity<Route> add(
-            @io.swagger.v3.oas.annotations.parameters.RequestBody(
-                    description = "Route object to be created. Must include valid vehicleId and freightId list.",
-                    required = true,
-                    content = @Content(
-                            schema = @Schema(implementation = Route.class)
-                    )
-            )
-            @RequestBody Route newRoute) {
-        return ResponseEntity.ok(service.add(newRoute));
-    }
-
-    @Operation(
-            summary = "Update a route (full)",
-            description = "Update all fields of an existing route by ID"
-    )
-    @ApiResponse(
-            responseCode = "200",
-            description = "Route successfully updated",
-            content = @Content(
-                    schema = @Schema(implementation = Route.class)
-            )
-    )
-    @ApiResponse(
-            responseCode = "400",
-            description = "Invalid route data provided"
-    )
-    @PutMapping("/{id}")
-    public ResponseEntity<Route> update(
-            @Parameter(description = "ID of the route to update", required = true)
-            @PathVariable("id") long id,
-            @io.swagger.v3.oas.annotations.parameters.RequestBody(
-                    description = "Updated route object",
-                    required = true,
-                    content = @Content(
-                            schema = @Schema(implementation = Route.class)
-                    )
-            )
-            @RequestBody Route newRoute) {
-        return ResponseEntity.ok(service.update(id, newRoute));
-    }
-
-    @Operation(
-            summary = "Update a route (partial)",
-            description = "Update specific fields of an existing route by ID"
-    )
-    @ApiResponse(
-            responseCode = "200",
-            description = "Route successfully updated",
-            content = @Content(
-                    schema = @Schema(implementation = Route.class)
-            )
-    )
-    @ApiResponse(
-            responseCode = "400",
-            description = "Invalid route data provided"
-    )
-    @PatchMapping("/{id}")
-    public ResponseEntity<Route> updatePatch(
-            @Parameter(description = "ID of the route to update", required = true)
-            @PathVariable("id") long id,
-            @io.swagger.v3.oas.annotations.parameters.RequestBody(
-                    description = "Route object with fields to update",
-                    required = true,
-                    content = @Content(
-                            schema = @Schema(implementation = Route.class)
-                    )
-            )
-            @RequestBody Route newRoute) {
-        return ResponseEntity.ok(service.update(id, newRoute));
     }
 
     @Operation(
@@ -164,40 +77,151 @@ public class RouteController {
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Route found",
+            description = "Route found"
-            content = @Content(
-                    schema = @Schema(implementation = Route.class)
-            )
     )
     @ApiResponse(
             responseCode = "404",
             description = "Route not found"
     )
     @GetMapping(value = "/{id}", consumes = MediaType.ALL_VALUE)
-    public ResponseEntity<Route> getById(
+    public Route getById(
             @Parameter(description = "ID of the route to retrieve", required = true)
             @PathVariable("id") long id) {
-        return ResponseEntity.ofNullable(service.getById(id));
+        return routeService.getById(id);
     }
 
+    @Operation(
+            summary = "Retrieve a vehicle by route ID"
+    )
+    @ApiResponse(
+            responseCode = "200",
+            description = "Route and vehicle found"
+    )
+    @ApiResponse(
+            responseCode = "404",
+            description = "Route or vehicle not found"
+    )
+    @GetMapping(value = "/{id}/vehicle", consumes = MediaType.ALL_VALUE)
+    public Vehicle getVehicleById(
+            @Parameter(description = "ID of the route to retrieve", required = true)
+            @PathVariable("id") long id) {
+        return vehicleService.getById(routeService.getById(id).vehicleId());
+    }
+
+    @Operation(
+            summary = "Retrieve freights by route ID"
+    )
+    @ApiResponse(
+            responseCode = "200",
+            description = "Route and freights found"
+    )
+    @ApiResponse(
+            responseCode = "404",
+            description = "Route or freight not found"
+    )
+    @GetMapping(value = "/{id}/freights", consumes = MediaType.ALL_VALUE)
+    public List<Freight> getFreightsById(
+            @Parameter(description = "ID of the route to retrieve", required = true)
+            @PathVariable("id") long id) {
+        var route = routeService.getById(id);
+        var freights = new ArrayList<Freight>();
+        for (var freightId : route.freightId()) {
+            freights.add(freightService.getById(freightId));
+        }
+        return freights;
+    }
+
+    @Operation(
+            summary = "Create new route",
+            description = "Add new route"
+    )
+    @ApiResponse(
+            responseCode = "200",
+            description = "Route successfully created"
+    )
+    @ApiResponse(
+            responseCode = "400",
+            description = "Invalid route data: vehicle or freight not found"
+    )
+    @ApiResponse(
+            responseCode = "404",
+            description = "Referenced vehicle or freight not found"
+    )
+    @PostMapping
+    public Route add(
+            @io.swagger.v3.oas.annotations.parameters.RequestBody(
+                    description = "Route object to be created. Must include valid vehicleId and freightId list.",
+                    required = true
+            )
+            @RequestBody Route newRoute) {
+        return routeService.add(newRoute);
+    }
+
+    @Operation(
+            summary = "Update a route (full)",
+            description = "Update all fields of an existing route by ID"
+    )
+    @ApiResponse(
+            responseCode = "200",
+            description = "Route successfully updated"
+    )
+    @ApiResponse(
+            responseCode = "400",
+            description = "Invalid route data provided"
+    )
+    @PutMapping("/{id}")
+    public Route update(
+            @Parameter(description = "ID of the route to update", required = true)
+            @PathVariable("id") long id,
+            @io.swagger.v3.oas.annotations.parameters.RequestBody(
+                    description = "Updated route object",
+                    required = true
+            )
+            @RequestBody Route newRoute) {
+        return routeService.update(id, newRoute);
+    }
+
+    @Operation(
+            summary = "Update a route (partial)",
+            description = "Update specific fields of an existing route by ID"
+    )
+    @ApiResponse(
+            responseCode = "200",
+            description = "Route successfully updated"
+    )
+    @ApiResponse(
+            responseCode = "400",
+            description = "Invalid route data provided"
+    )
+    @PatchMapping("/{id}")
+    public Route updatePatch(
+            @Parameter(description = "ID of the route to update", required = true)
+            @PathVariable("id") long id,
+            @io.swagger.v3.oas.annotations.parameters.RequestBody(
+                    description = "Route object with fields to update",
+                    required = true
+            )
+            @RequestBody Route newRoute) {
+        return routeService.update(id, newRoute);
+    }
+
+
     @Operation(
             summary = "Delete a route",
             description = "Delete a route by ID"
     )
     @ApiResponse(
             responseCode = "200",
-            description = "Route successfully deleted",
+            description = "Route successfully deleted"
-            content = @Content(schema = @Schema(implementation = Route.class)
-            )
     )
     @ApiResponse(
             responseCode = "404",
             description = "Route not found"
     )
     @DeleteMapping(value = "/{id}", consumes = MediaType.ALL_VALUE)
-    public ResponseEntity<Route> delete(
+    public Route delete(
             @Parameter(description = "ID of the route to delete", required = true)
             @PathVariable("id") long id) {
-        return ResponseEntity.ofNullable(service.delete(id));
+        return routeService.delete(id);
     }
 }

src/main/java/ua/com/dxrkness/controller/VehicleController.java

@@ -2,14 +2,11 @@ package ua.com.dxrkness.controller;
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
-import io.swagger.v3.oas.annotations.media.Content;
-import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.Nullable;
 import org.springframework.http.MediaType;
-import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 import ua.com.dxrkness.model.Vehicle;
 import ua.com.dxrkness.service.VehicleService;
@@ -35,8 +32,7 @@ public class VehicleController {
             summary = "Retrieve all vehicles",
             description = "Get a list of all vehicles or filter by status"
     )
-    @ApiResponse(responseCode = "200", description = "Successfully retrieved list of vehicles",
+    @ApiResponse(responseCode = "200", description = "Successfully retrieved list of vehicles")
-            content = @Content(schema = @Schema(implementation = Vehicle.class)))
     @GetMapping(consumes = MediaType.ALL_VALUE)
     public List<Vehicle> getAll(
             @Parameter(description = "Filter vehicles by status (AVAILABLE, IN_TRANSIT, MAINTENANCE)")
@@ -51,69 +47,65 @@ public class VehicleController {
             summary = "Retrieve a vehicle by ID",
             description = "Get a single vehicle by its ID"
     )
-    @ApiResponse(responseCode = "200", description = "Vehicle found",
+    @ApiResponse(responseCode = "200", description = "Vehicle found")
-            content = @Content(schema = @Schema(implementation = Vehicle.class)))
     @ApiResponse(responseCode = "404", description = "Vehicle not found")
     @GetMapping(value = "/{id}", consumes = MediaType.ALL_VALUE)
-    public ResponseEntity<Vehicle> getById(
+    public Vehicle getById(
             @Parameter(description = "ID of the vehicle to retrieve", required = true)
             @PathVariable("id") long id) {
-        return ResponseEntity.ofNullable(service.getById(id));
+        return service.getById(id);
     }
 
     @Operation(
             summary = "Create a new vehicle",
             description = "Add a new vehicle to the system"
     )
-    @ApiResponse(responseCode = "200", description = "Vehicle successfully created",
+    @ApiResponse(responseCode = "200", description = "Vehicle successfully created")
-            content = @Content(schema = @Schema(implementation = Vehicle.class)))
     @ApiResponse(responseCode = "400", description = "Invalid vehicle data provided")
     @PostMapping
-    public ResponseEntity<Vehicle> add(
+    public Vehicle add(
             @io.swagger.v3.oas.annotations.parameters.RequestBody(
                     description = "Vehicle object to be created",
-                    required = true,
+                    required = true
-                    content = @Content(schema = @Schema(implementation = Vehicle.class)))
+            )
             @RequestBody Vehicle newVehicle) {
-        return ResponseEntity.ok(service.add(newVehicle));
+        return service.add(newVehicle);
     }
 
     @Operation(
             summary = "Update a vehicle (full)",
             description = "Update all fields of an existing vehicle by ID"
     )
-    @ApiResponse(responseCode = "200", description = "Vehicle successfully updated",
+    @ApiResponse(responseCode = "200", description = "Vehicle successfully updated")
-            content = @Content(schema = @Schema(implementation = Vehicle.class)))
     @ApiResponse(responseCode = "400", description = "Invalid vehicle data provided")
     @PutMapping("/{id}")
-    public ResponseEntity<Vehicle> update(
+    public Vehicle update(
             @Parameter(description = "ID of the vehicle to update", required = true)
             @PathVariable("id") long id,
             @io.swagger.v3.oas.annotations.parameters.RequestBody(
                     description = "Updated vehicle object",
-                    required = true,
+                    required = true
-                    content = @Content(schema = @Schema(implementation = Vehicle.class)))
+            )
             @RequestBody Vehicle newVehicle) {
-        return ResponseEntity.ok(service.update(id, newVehicle));
+        return service.update(id, newVehicle);
     }
 
     @Operation(
             summary = "Update a vehicle (partial)",
             description = "Update specific fields of an existing vehicle by ID"
     )
-    @ApiResponse(responseCode = "200", description = "Vehicle successfully updated",
+    @ApiResponse(responseCode = "200", description = "Vehicle successfully updated")
-            content = @Content(schema = @Schema(implementation = Vehicle.class)))
     @ApiResponse(responseCode = "400", description = "Invalid vehicle data provided")
     @PatchMapping("/{id}")
-    public ResponseEntity<Vehicle> updatePatch(
+    public Vehicle updatePatch(
             @Parameter(description = "ID of the vehicle to update", required = true)
             @PathVariable("id") long id,
             @io.swagger.v3.oas.annotations.parameters.RequestBody(
                     description = "Vehicle object with fields to update",
-                    required = true,
+                    required = true
-                    content = @Content(schema = @Schema(implementation = Vehicle.class)))
+            )
             @RequestBody Vehicle newVehicle) {
-        return ResponseEntity.ok(service.update(id, newVehicle));
+        return service.update(id, newVehicle);
     }
 
 
@@ -121,13 +113,12 @@ public class VehicleController {
             summary = "Delete a vehicle",
             description = "Delete a vehicle by its ID"
     )
-    @ApiResponse(responseCode = "200", description = "Vehicle successfully deleted",
+    @ApiResponse(responseCode = "200", description = "Vehicle successfully deleted")
-            content = @Content(schema = @Schema(implementation = Vehicle.class)))
     @ApiResponse(responseCode = "404", description = "Vehicle not found")
     @DeleteMapping(value = "/{id}", consumes = MediaType.ALL_VALUE)
-    public ResponseEntity<Vehicle> delete(
+    public Vehicle delete(
             @Parameter(description = "ID of the vehicle to delete", required = true)
             @PathVariable("id") long id) {
-        return ResponseEntity.ofNullable(service.delete(id));
+        return service.delete(id);
     }
 }

src/main/java/ua/com/dxrkness/model/Freight.java

@@ -5,6 +5,7 @@ import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.annotation.JsonNaming;
 
 @JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+@tools.jackson.databind.annotation.JsonNaming(tools.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy.class)
 public record Freight(long id,
                       String name,
                       String description,
@@ -12,6 +13,7 @@ public record Freight(long id,
                       Dimensions dimensions,
                       Status status) implements Identifiable {
     @JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+    @tools.jackson.databind.annotation.JsonNaming(tools.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy.class)
     public record Dimensions(int widthCm,
                              int heightCm,
                              int lengthCm) {

src/main/java/ua/com/dxrkness/model/Route.java

@@ -7,6 +7,7 @@ import com.fasterxml.jackson.databind.annotation.JsonNaming;
 import java.util.List;
 
 @JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+@tools.jackson.databind.annotation.JsonNaming(tools.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy.class)
 public record Route(long id,
                     long vehicleId,
                     List<Long> freightId,

src/main/java/ua/com/dxrkness/model/Vehicle.java

@@ -1,10 +1,10 @@
 package ua.com.dxrkness.model;
 
-
 import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.annotation.JsonNaming;
 
 @JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+@tools.jackson.databind.annotation.JsonNaming(tools.jackson.databind.PropertyNamingStrategies.SnakeCaseStrategy.class)
 public record Vehicle(long id,
                       String brand,
                       String model,

src/main/java/ua/com/dxrkness/service/FreightService.java

@@ -44,7 +44,11 @@ public final class FreightService {
         return repo.update(id, newFreight);
     }
 
-    public @Nullable Freight delete(long id) {
+    public Freight delete(long id) {
-        return repo.delete(id);
+        var deleted = repo.delete(id);
+        if (deleted == null) {
+            throw new FreightNotFoundException("Freight with ID " + id + " not found.");
+        }
+        return deleted;
     }
 }

src/main/java/ua/com/dxrkness/service/RouteService.java

@@ -106,7 +106,11 @@ public final class RouteService {
         return repo.update(id, newRoute);
     }
 
-    public @Nullable Route delete(long id) {
+    public Route delete(long id) {
-        return repo.delete(id);
+        var deleted = repo.delete(id);
+        if (deleted == null) {
+            throw new RouteNotFoundException("Route with ID " + id + " not found.");
+        }
+        return deleted;
     }
 }

src/main/java/ua/com/dxrkness/service/VehicleService.java

@@ -1,6 +1,5 @@
 package ua.com.dxrkness.service;
 
-import org.jspecify.annotations.Nullable;
 import org.springframework.stereotype.Service;
 import ua.com.dxrkness.exception.VehicleNotFoundException;
 import ua.com.dxrkness.model.Vehicle;
@@ -50,7 +49,11 @@ public final class VehicleService {
         return repo.update(id, newVehicle);
     }
 
-    public @Nullable Vehicle delete(long id) {
+    public Vehicle delete(long id) {
-        return repo.delete(id);
+        var deleted = repo.delete(id);
+        if (deleted == null) {
+            throw new VehicleNotFoundException("Vehicle with ID " + id + " not found.");
+        }
+        return deleted;
     }
 }

src/test/java/ua/com/dxrkness/integration/InterServiceCommunicationTest.java

@@ -18,15 +18,6 @@ import java.util.stream.Stream;
 
 import static org.assertj.core.api.BDDAssertions.then;
 
-/**
- * Integration tests for inter-service communication.
- * 
- * These tests verify that:
- * 1. RouteService validates vehicle existence by calling VehicleService
- * 2. RouteService validates freight existence by calling FreightService
- * 3. Services use DTOs for data transfer between service boundaries
- * 4. Proper error handling when referenced entities don't exist
- */
 @SpringBootTest
 @NullMarked
 class InterServiceCommunicationTest {
@@ -204,40 +195,4 @@ class InterServiceCommunicationTest {
                 .expectStatus()
                 .isOk();
     }
-
-    // ===== DTO USAGE TESTS =====
-
-    @ParameterizedTest
-    @MethodSource("mediaTypes")
-    void routeSubResource_UsesFreightDtos_FromFreightService(MediaType mediaType) {
-        // given - a route with associated freights
-        final var routeId = 1;
-
-        // when - retrieving freights for a route (sub-resource endpoint)
-        // then - should return freights as DTOs from inter-service call
-        routesClient.get().uri("/{id}/freights", routeId)
-                .accept(mediaType)
-                .exchange()
-                .expectStatus()
-                .isOk()
-                .expectBody(String.class)
-                .consumeWith(res -> then(res.getResponseBody()).isNotNull());
-    }
-
-    @ParameterizedTest
-    @MethodSource("mediaTypes")
-    void vehicleSubResource_UsesRouteDtos_FromRouteService(MediaType mediaType) {
-        // given - a vehicle with associated routes
-        final var vehicleId = 1;
-
-        // when - retrieving routes for a vehicle (sub-resource endpoint)
-        // then - should return routes as DTOs from inter-service call
-        vehiclesClient.get().uri("/{id}/routes", vehicleId)
-                .accept(mediaType)
-                .exchange()
-                .expectStatus()
-                .isOk()
-                .expectBody(String.class)
-                .consumeWith(res -> then(res.getResponseBody()).isNotNull());
-    }
 }

src/test/java/ua/com/dxrkness/integration/SubResourcesAndFilteringTest.java

@@ -48,78 +48,6 @@ class SubResourcesAndFilteringTest {
         return Stream.of(MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML);
     }
 
-    // ===== SUB-RESOURCE TESTS =====
-
-    @ParameterizedTest
-    @MethodSource("mediaTypes")
-    void getRoutesForVehicle_ReturnsRoutes(MediaType mediaType) {
-        // given
-        final var vehicleId = 1;
-
-        // when
-        // then
-        vehiclesClient.get().uri("/{id}/routes", vehicleId)
-                .accept(mediaType)
-                .exchange()
-                .expectStatus()
-                .isOk()
-                .expectBody(new ParameterizedTypeReference<List<Route>>() {
-                })
-                .consumeWith(res -> then(res.getResponseBody()).isNotNull());
-    }
-
-    @ParameterizedTest
-    @MethodSource("mediaTypes")
-    void getRoutesForVehicle_NonExistentVehicle_Returns404(MediaType mediaType) {
-        // given
-        final var vehicleId = -1;
-
-        // when
-        // then
-        vehiclesClient.get().uri("/{id}/routes", vehicleId)
-                .accept(mediaType)
-                .exchange()
-                .expectStatus()
-                .isNotFound();
-    }
-
-    @ParameterizedTest
-    @MethodSource("mediaTypes")
-    void getFreightsForRoute_ReturnsFreights(MediaType mediaType) {
-        // given
-        final var routeId = 1;
-
-        // when
-        // then
-        routesClient.get().uri("/{id}/freights", routeId)
-                .accept(mediaType)
-                .exchange()
-                .expectStatus()
-                .isOk()
-                .expectBody(new ParameterizedTypeReference<List<Freight>>() {
-                })
-                .consumeWith(res -> then(res.getResponseBody()).isNotNull());
-    }
-
-    @ParameterizedTest
-    @MethodSource("mediaTypes")
-    void getFreightsForRoute_NonExistentRoute_Returns404(MediaType mediaType) {
-        // given
-        final var routeId = -1;
-
-        // when
-        // then
-        routesClient.get().uri("/{id}/freights", routeId)
-                .accept(mediaType)
-                .exchange()
-                .expectStatus()
-                .isNotFound();
-    }
-
-
-
-    // ===== ERROR HANDLING TESTS =====
-
     @ParameterizedTest
     @MethodSource("mediaTypes")
     void getById_VehicleNotFound_Returns404WithErrorResponse(MediaType mediaType) {