Redis – Spring Boot Microservices – RestTemplate Null Pointer Exception in JUnit Test

I have a problem running Junit Service in my spring-boot microservice. I defined bearer token getting from /authenticate/login. It is valid. I can send a request to any service through Postman.

I cannot run the test method after copying bearer token and defining it here as shown below.

Here is the its test method

@DisplayName("Get Order - Success Scenario")
    @Test
    void test_When_Order_Success() {

        String bearerToken = "eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJVc2VyIiwiaXNzIjoiUk9MRV9VU0VSICIsImlhdCI6MTY3MTQ4ODgyMiwiZXhwIjoxNjcxNDg4OTQyfQ.g83kKmFzDH539ZcpxM9D8bE_famFOevkOqNst_E8YG07b4yR4cEqcrySvz36vw8GJxTKm9gUQIM1J_G8cC5RGQ";

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        headers.set("Authorization", "Bearer " + bearerToken);

        HttpEntity<String> request = new HttpEntity<String>(headers);

        //Mocking
        Order order = getMockOrder();
        when(orderRepository.findById(anyLong()))
                .thenReturn(Optional.of(order));

        when(restTemplate.exchange(
                "http://PRODUCT-SERVICE/product/" + order.getProductId(),
                HttpMethod.GET, request, ProductResponse.class).getBody()).thenReturn(getMockProductResponse());

        when(restTemplate.exchange(
                "http://PAYMENT-SERVICE/payment/order/" + order.getId(),
                HttpMethod.GET, request, PaymentResponse.class).getBody()).thenReturn(getMockPaymentResponse());

        //Actual
        OrderResponse orderResponse = orderService.getOrderDetails(1,bearerToken);

        //Verification
        verify(orderRepository, times(1)).findById(anyLong());
        verify(restTemplate, times(1)).getForObject(
                "http://PRODUCT-SERVICE/product/" + order.getProductId(),
                ProductResponse.class);
        verify(restTemplate, times(1)).getForObject(
                "http://PAYMENT-SERVICE/payment/order/" + order.getId(),
                PaymentResponse.class);

        //Assert
        assertNotNull(orderResponse);
        assertEquals(order.getId(), orderResponse.getOrderId());
    }

Here is the error shown below.

java.lang.NullPointerException: Cannot invoke "org.springframework.http.ResponseEntity.getBody()" because the return value of "org.springframework.web.client.RestTemplate.exchange(String, org.springframework.http.HttpMethod, org.springframework.http.HttpEntity, java.lang.Class, Object[])" is null

How can I fix the issue?

Here is the repo : Link

To run the app,

1. Run Service Registery (Eureka Server)

2. Run config server

3. Run zipkin and redis through these commands shown below on docker

   docker run -d -p 9411:9411 openzipkin/zipkin
   docker run -d –name redis -p 6379:6379 redis

4. Run api gateway

5. Run other services