如何在 java 中用另一个注解来注解一个注解？

Question

I want to create a custom annotation and annotate it with another annotation like below:

@Documented
@Target({ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
//@Size(min = min, max = max, message = defaultMessage) //neither this works
//@Min(6) //nor this works
public @interface PasswordString {
    String message() default defaultMessage;

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};

    class PasswordStringAnnotationConfig {
        public static final int min = 6;
        public static final int max = 100;
        public static final String defaultMessage = "Password must be between " + min + " and " + max + "characters";
    }
}

I know I can simply create a class that implement ConstraintValidator but I wonder if I can achieve this easier functionality.

Answer 1

adding this annotation

@Constraint(validatedBy = {})

solved the problem.

Although this annotation is present in the declaration of Min and of Size annotations, but I don't know why it was not applied on the custom annotation automatically and needed to be defined explicitly.