import java.io.Serializable; class WildcardBounds { class BoundedGeneric<B extends Cloneable> {} class BoundedGeneric2<B extends Number> {} class BoundedGeneric3<B extends Number & Cloneable> {} void use() { BoundedGeneric<? extends Serializable> a; BoundedGeneric<? extends Serializable> b; BoundedGeneric<? extends Serializable> c; } }