Question

In my Android application, i have the following classes:

public abstract class A implements IA {
    private void findAnnotations() {
        Field[] fields = getClass().getFields();

        // Get all fields of the object annotated for serialization
        if (fields != null && fields.length > 0) {
            for (Field f : fields) {
                Annotation[] a = f.getAnnotations();

                if (annotation != null) {
                    // Do something
                }
            }
        }

        return serializationInfoList
                .toArray(new SoapSerializationFieldInfo[serializationInfoList
                        .size()]);
    }
}

and

public abstract class B extends A {
    @MyAnnotation(Name="fieldDelaredInB")
    public long fieldDelaredInB;
}

When i call B.findAnnotations(), i can see that getClass().getFields() returns the fields declared in B – fieldDelaredInB, e.g., but no annotations for these fields are returned – i.e, i get null when i call f.getAnnotations(), f.getDeclaredAnnotations() or whatsoever.

Is this an issue of a superclass unfamiliar with attributes of derived classes? seems weird, considering the fact that the fields of the derived class DO appear when i call getFields() from the superclass.

Any ideas of what am i missing?

Thanks,
Harel

Answer 1

An annotation is not loaded at runtime unless it is marked for runtime retention with @Retention(RetentionPolicy.RUNTIME). You must place this @Retention annotation on your @MyAnnotation annotation:

@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {
    ...
}