NullnessBound.java

import org.checkerframework.checker.nullness.qual.*;

class NullnessBound {

    public void test() {
        Gen1<@Nullable String> t1 = new Gen1<@Nullable String>();
        t1.add(null);

        Gen2<@Nullable String> t2 = new Gen2<@Nullable String>();
        t2.add(null);

        Gen1<@NonNull String> t3;
        //:: error: (type.argument.type.incompatible)
        Gen2<@NonNull String> t4;
    }

    class Gen1<E extends @Nullable Object> {
        public void add(E e) {}
    }

    class Gen2<@Nullable E> {
        public void add(E e) {}
    }
}