How to identify an annotation that applies exclusively to classes?

To define an annotation in Java that applies only to classes, you should use the meta-annotation @Target with the parameter ElementType.TYPE. This restricts the annotation's scope to classes, interfaces, enums, and annotations.

Example of defining such an annotation:

import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

@Target(ElementType.TYPE) // applicable only to classes, interfaces, enums, and annotations
@Retention(RetentionPolicy.RUNTIME) // available at runtime
public @interface MyClassAnnotation {
    String value() default "";
}

Now, @MyClassAnnotation can only be placed above class, interface, or enum declarations, but not on methods or fields.