JAXB won't handle my interfaces even with @XmlAnyElement

Here's some UML:

I'm trying to marshall those Components which are stored in a HashMap<String, Component> with this annotated code as explained in the Unofficial JAXB guide:

/**
 * This is a marshalling method which returns each
 * of this entity's components in a Collection
 * @return A collection of this entity's components
 */
@XmlElementWrapper(name="components")
@XmlAnyElement
@XmlElementRef
public Collection<Component> getComponentSet() {
    return components.values();
}

And in each Component implementation I put @XmlRootElement

But JAXB is stuck on the following exception and all my attempts to get past it have been futile:

Exception in thread "main" com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions
mycrap.core.components.Component is an interface and JAXB can't handle interfaces.
    this problem is related to the following location:
        at mycrap.core.components.Component
        at public java.util.Collection tobacco.core.components.Entity.getComponentSet()
        at mycrap.core.components.Entity

I've been dealing with this for a couple of days to no avail. Other posts I find don't seem to get this exception at this point, once @XmlAnyElement's in place. What have I done wrong?! :(