Specification of abstract method PermissionCollection.implies(Permission permission)
looks too brief.

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public abstract boolean implies(Permission permission)

    Checks to see if the specified permission is implied by the collection of Permission objects held in this PermissionCollection.

    Parameters:
        permission - the Permission object to compare.
    Returns:
        true if "permission" is implied by the permissions in the collection, false if not.
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It is not clear what means "implied by the permissions in the collection".

Is it conjunction of impiles() invoked for each member of collection ? Or disjucntion ?
Or something else ?
Is it correct such extreme case when BasicPermission.newPermissionCollection().implies() always return true or false ? In other word is subclass of PermissionCollection free to define what means "implied by the permissions in the collection" or there are some restrictions on interpretation of this phrase.