TestSuperCapture.java

import java.util.ArrayList;

class TestSuperCapture {
    
    static class TestSuper {}
    static class TestSub extends TestSuper {}
    static class TestSub2 extends TestSub {}
    static class TestSub3 extends TestSub2 {}
    
    public static void main(String[] args) {
        /* capture objects that there super-class is TestSub */
        ArrayList<? super TestSub> list = new ArrayList<>();
        
        list.add(new TestSub2());
        list.add(new TestSub3());
    }
}