Why REST controllers are essential in Spring Boot - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a REST controller in Spring Boot.

Spring Boot

@[1]
public class MyController {
}

Drag options to blanks, or click blank then click option'

ARepository

BService

CComponent

DRestController

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service instead of @RestController

Forgetting the @RestController annotation

Using @Component which is too generic

The @RestController annotation marks the class as a REST controller, which handles HTTP requests and returns data as JSON or XML.

2fill in blank

medium

Complete the code to map a GET request to the method.

Spring Boot

@GetMapping("/[1]")
public String greet() {
    return "Hello";
}

Drag options to blanks, or click blank then click option'

Ahello

Bpost

Cput

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTP method names like 'post' in a GET mapping

Leaving the path empty when a path is needed

Using incorrect HTTP method annotations

The @GetMapping("/hello") annotation maps HTTP GET requests for the path '/hello' to this method.

3fill in blank

hard

Fix the error in the method signature to accept a path variable.

Spring Boot

@GetMapping("/user/[1]")
public String getUser(@PathVariable String id) {
    return "User " + id;
}

Drag options to blanks, or click blank then click option'

A:id

B{id}

C<id>

D(id)

Attempts:

3 left

💡 Hint

Common Mistakes

Using colon or angle brackets instead of curly braces

Not matching the path variable name with the method parameter

Omitting the @PathVariable annotation

Path variables in Spring Boot are enclosed in curly braces like {id} in the URL mapping.

4fill in blank

hard

Fill both blanks to create a POST endpoint that accepts JSON data.

Spring Boot

@PostMapping("/[1]")
public ResponseEntity<String> createItem(@[2] Item item) {
    return ResponseEntity.ok("Created");
}

Drag options to blanks, or click blank then click option'

Aitems

BRequestBody

CPathVariable

DRequestParam

Attempts:

3 left

💡 Hint

Common Mistakes

Using @PathVariable or @RequestParam instead of @RequestBody for JSON data

Using singular resource name for POST endpoint

Omitting the annotation for the method parameter

The @PostMapping("/items") maps POST requests to '/items'. The @RequestBody annotation tells Spring to convert JSON from the request body into the Item object.

5fill in blank

hard

Fill all three blanks to return a JSON map with filtered data.

Spring Boot

Map<String, Integer> result = items.stream()
    .filter(item -> item.getQuantity() [1] 10)
    .collect(Collectors.toMap(
        item -> item.getName().[2](),
        item -> item.getQuantity() [3] 1
    ));

Drag options to blanks, or click blank then click option'

A>

BtoUpperCase

C+

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' in filter

Using toLowerCase() instead of toUpperCase()

Subtracting instead of adding in the map value

This code filters items with quantity greater than 10, converts their names to uppercase for keys, and adds 1 to their quantity for values in the resulting map.