@Parameter and @Schema annotations in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

How does @Parameter affect API documentation?

Consider a Spring Boot REST controller method with a parameter annotated by @Parameter(description = "User ID"). What effect does this annotation have on the generated OpenAPI documentation?

Spring Boot

public ResponseEntity<User> getUser(@Parameter(description = "User ID") @PathVariable String id) {
    // method body
}

A It changes the parameter type in the API to a custom object.

B It automatically validates the parameter value before method execution.

C It adds a description to the parameter in the OpenAPI docs, helping API consumers understand its purpose.

D It hides the parameter from the generated API documentation.

💡 Hint

Think about how @Parameter is used to enhance API documentation metadata.

The @Parameter annotation is used to add metadata like descriptions to method parameters in OpenAPI documentation. It does not affect validation or parameter types directly.

📝 Syntax

intermediate

Correct usage of @Schema to define a model property

Which of the following code snippets correctly uses @Schema to specify that a field is required and has a maximum length of 50 characters?

Spring Boot

public class User {
    @Schema(required = true, maxLength = 50)
    private String name;
}

A @Schema(required = true, maxLength = 50)

B @Schema(required = "true", maxLength = 50)

C @Schema(required = true, maxLength = "50")

D @Schema(required = true, maxLength = 50, description = 100)

💡 Hint

Check the data types of the annotation attributes.

The @Schema annotation attributes require correct data types: 'required' is boolean, 'maxLength' is int. Passing strings or wrong types causes errors.

🔧 Debug

advanced

Why does this @Schema annotation cause a runtime error?

Given the code snippet below, why does the application fail to start? public class Product { @Schema(example = 12345) private String code; }

Spring Boot

public class Product {
    @Schema(example = 12345)
    private String code;
}

A The field 'code' must be public for @Schema to work.

B The example attribute expects a String value, but an integer is provided, causing a type mismatch error.

C The @Schema annotation requires a description attribute to work properly.

D The example attribute cannot be used on String fields.

💡 Hint

Check the expected data type for the example attribute in @Schema.

The example attribute in @Schema expects a String value. Providing an integer causes a type mismatch error during startup.

🧠 Conceptual

advanced

Difference between @Parameter and @Schema annotations

Which statement best describes the difference between @Parameter and @Schema annotations in Spring Boot OpenAPI integration?

A @Parameter and @Schema are interchangeable and serve the same purpose.

B @Parameter validates input values, and @Schema generates API documentation for endpoints.

C @Parameter is only for request bodies, and @Schema is only for response bodies.

D @Parameter is used to describe method parameters in API endpoints, while @Schema describes the structure of data models or properties.

💡 Hint

Think about what each annotation targets: parameters vs data models.

@Parameter annotates method parameters to add metadata for API docs, while @Schema annotates data model classes or fields to define their schema details.

❓ state_output

expert

What is the effect of combining @Parameter and @Schema on a method parameter?

Consider this method parameter in a Spring Boot controller: @GetMapping("/items/{id}") public Item getItem( @Parameter(description = "Item identifier") @Schema(example = "42", required = true) @PathVariable String id) { // method body } What will be the combined effect on the generated OpenAPI documentation for this parameter?

Spring Boot

@Parameter(description = "Item identifier")
@Schema(example = "42", required = true)
@PathVariable String id

A The parameter will have a description, be marked required, and show an example value in the OpenAPI docs.

B The @Schema annotation will override @Parameter, so only example and required are shown without description.

C Only the @Parameter description is used; @Schema is ignored on method parameters.

D The parameter will be hidden from the OpenAPI documentation due to conflicting annotations.

💡 Hint

Both annotations add complementary metadata for API documentation.

Using both @Parameter and @Schema on a method parameter enriches the OpenAPI docs with description, example, and required status together.