[Solved] Given this controller method: @PostMapping("/items") public ResponseEnt... } If the client sends an empty string for title, what is the likely error in the code that prevents validation from working? | Spring Boot

Spring Boot - Request and Response Handling

Given this controller method:

@PostMapping("/items")
public ResponseEntity addItem(@RequestBody ItemDto item) {
    return ResponseEntity.ok("Item added");
}

And this DTO:

public class ItemDto {
  @NotBlank
  private String title;
}

If the client sends an empty string for title, what is the likely error in the code that prevents validation from working?

AMissing <code>@Validated</code> on the controller class.

BMissing <code>@Valid</code> on the method parameter.

CUsing <code>@NotBlank</code> instead of <code>@NotNull</code>.

DReturning ResponseEntity instead of void.

Step-by-Step Solution

Solution:

Step 1: Check validation trigger on method parameter
Validation on request body requires @Valid on the parameter to trigger validation.
Step 2: Identify missing or incorrect annotation
If @Valid is missing, validation annotations like @NotBlank are ignored.
Final Answer:
Missing @Valid on the method parameter. -> Option B
Quick Check:
@Valid missing disables validation = D [OK]

Quick Trick: Always put @Valid on request body parameters [OK]

Common Mistakes:

Master "Request and Response Handling" in Spring Boot

9 interactive learning modes - each teaches the same concept differently

More Spring Boot Quizzes

Given this controller method: