The issue with several methods is that in each method of AnnotationAccessor I will need to have the logic : 
   if (body instanceof BodyDeclaration) getModifier(...)
   if (body instanceof PackageDeclaration) getAnnotations(...)
It is better to factorize this logic in a dedicated method.
As it is a private method used inside AnnotationAccessor I don't think it will add lot of confusion
And also it was already the case before because ((BodyDeclaration) body).modifiers() actually returns list of modifiers and annotations

wdyt ?