Java Bean Validation ensures input meets certain constraints before processing.
In Spring, you can use annotations like @Valid in a controller to validate input data against Java Bean constraints. For example, if a user's email must not be blank, you can add @NotBlank to the email field. When a request is made, Spring checks these annotations and rejects requests that don't meet the criteria, preventing invalid data from reaching deeper layers of the application.
Additional Notes
How does Java Bean Validation work in a Spring controller?