Main.java

import java.util.Collection;
import java.util.Iterator;

public class Main {

    interface A {}

    class B {
        void add(A... a) {}
        void add(Collection<A> c) {}
    }

    <T extends A> T getA() {
        return null;
    }

    void test() {
        B b = new B();
        b.add(this.<C>getA());
    }

    class C implements A, Collection<A> {
        @Override
        public int size() {
            return 0;
        }

        @Override
        public boolean isEmpty() {
            return false;
        }

        @Override
        public boolean contains(Object o) {
            return false;
        }

        @Override
        public Iterator<A> iterator() {
            return null;
        }

        @Override
        public Object[] toArray() {
            return new Object[0];
        }

        @Override
        public <T> T[] toArray(T[] a) {
            return null;
        }

        @Override
        public boolean add(A a) {
            return false;
        }

        @Override
        public boolean remove(Object o) {
            return false;
        }

        @Override
        public boolean containsAll(Collection<?> c) {
            return false;
        }

        @Override
        public boolean addAll(Collection<? extends A> c) {
            return false;
        }

        @Override
        public boolean removeAll(Collection<?> c) {
            return false;
        }

        @Override
        public boolean retainAll(Collection<?> c) {
            return false;
        }

        @Override
        public void clear() {}
    }
}