REST/Spring/Mokito

Question 1

What is REST

Answer 1

1. Representational state transfer
2. Architecture style utilising http protocal/methods
3. Rest Client + Rest Server
4. using URI to identify each resource
5. POST, GET, PUT, DELETE
6. Resource can be ins format json, XML

Question 2

What is RESTful web service?

Answer 2

Web service implemented using REST style.
Usually used for:
export data for another application/system
Example: export all USD trades from ourside

Question 3

What is in HTTP request/response?

Answer 3

request: Http Methods, URI, Http version, Header(key-value pairs), Request Body(msg content)
response: Response code, http version. response header, response body.

Response Code:
200 OK
404 not found

Question 4

Implementation of Rest end point?

Answer 4

Using Spring framework web

@RestController
@RestMapping(value=”/api/recon”, method = RequestMethod.POST)
public ResponseEntity export(@RequestBody DashboardRequest request);

Using Jersey as a client
Spring:
RestTemplate execute(URL, method, requestCallbacl, requestExtractor)

Question 5

What is Spring IoC container?

Answer 5

1. Core of spring framework, create all the beans,
   resolve dependency between them, keep them alive until time to destroy. Managing the whole life cycle of the bean.
2. Use Dependency Injection
3. Most useful one - ApplicationContext
   more features than ‘BeanFactory’
   can resolve text properties in files
   can send event to event listener(ex: when app is started)

Question 6

Application Main class

Answer 6

@SpringBootApplication
= @EnableAutoConfiguration + @Configuration + @ComponentScan

AutoConfiguration helps what?
for Ex: auto configure JdbcTemplate if its present and a DataSource bean are available

Question 7

What is SpringBoot?

Answer 7

1. A Framework enables fast java app development using spring framework
2. Easy to use
3. when embedded tomcat server

Question 8

Difference between Mock and Spy

Answer 8

Mock
create a complete fake object, is the method is not stubbed, it will do nothing, return null

Spy
created a half real object, if the method is not stubbed, it will execute the actual method

Question 9

Steps in designing REST Services

Answer 9

1.Identify Object Model
each object with a unique : int Id;
2. Create Model URIs
Follow the resource heriachys
/devices
/devices/{id}

/configurations
/configurations/{id}

/devices/{id}/configurations
/devices/{id}/configurations/{id}

3. Determine Representations - structure, Json, XML
   Collections of Resource - only expose necessary fields to reduce API payload
   Single resource - can expose mode details fields
4. Assign HTTP Methods
5. More Actions
   1) Logging
   2) Security
   3) Discovery (retry)
   https: //restfulapi.net/rest-api-design-tutorial-with-example/#object-model

Question 10

Constructor Vs setter based DI?

Answer 10

Constructor DI:
enforces the order of initialisation
preventscircular dependencies,

Setter DI:
Setter DI allows circular dependencies
It is easy to miss a few setter calls when wiring the application together.
lazy initialisation - Setter-based DI helps us to inject the dependency only when it is required, as opposed to requiring it at construction time.

Question 11

log4j

Answer 11

log4j is a tool to help the programmer output log statements to a variety of output targets. In case of problems with an application, it is helpful to enable logging so that the problem can be located. With log4j it is possible to enable logging at runtime without modifying the application binary.