As I see there is some confusion related to validation annotations usage in Java. Let’s see a quick example of the three most confusing annotations from the Hibernate Validator.

@NotNull

public class User {

   @NotNull
   private String name;


   // ...
}

@NotEmpty

public class User {

   @NotEmpty
   private String name;


   // ...
}

Note: null and empty size/length values are not allowed, values with multiple spaces will pass this validation.

@NotBlank

public class User {

   @NotBlank
   private String name;


   // ...
}

Note: null values are not allowed and trimmed length must be greater than zero.

_{Title image by Matthias Böckel from Pixabay}