user31231234124 user31231234124 - 24 days ago 6
Android Question

Name clash because of same erasure

I have an interface like the following

public interface IDrawerItem<T, VH extends RecyclerView.ViewHolder> extends IItem<T, VH>, IExpandable<T, IDrawerItem>, ISubItem<IDrawerItem, IDrawerItem> {
void bindView(VH holder, List payloads);

}


Im getting the following error


Error:(44, 10) error: name clash: bindView(VH#1,List) in IDrawerItem
and bindView(VH#2,List) in IItem have the same erasure, yet
neither overrides the other where VH#1,VH#2 are type-variables: VH#1
extends ViewHolder declared in interface IDrawerItem VH#2 extends
ViewHolder declared in interface IItem


Why is that so?

Answer

Short answer: Because the signature cannot be changed. Extending an interface just adds more signatures to the interface.

Overriding can only be done in classes, not interfaces. You can not update the signature, but you can make a different implementation of that method using the same signature.

Interfaces just show a signature which have to be available in the class implementing it. For this reason you can change (override) the implementation in a subclass. The method signature (name and parameters) stay the same, so it still complies with the interface. There is no implementation to override in an interface, hence it shows only thát there is such method in any class implementing this interface, and that it is callable from the instantiated object.

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