Why use super in crazy generics module

[homosapi3n]

In MaxHolder or StrictProcessor class, the input param has been defined as Comparable<? super T>. Why use super instead of specific type T i.e. Comparable< T > ?
Can someone provide an example where each option would work but not other?

Adding the code snippet for more clarity:

public static class MaxHolder<T extends Comparable< T >> { // vs MaxHolder<T extends Comparable<? super T>>
private T max;

    public MaxHolder(T max) {
        this.max = max;
    }

    /**
     * Puts a new value to the holder. A new value is stored to the max, only if it is greater than current max value.
     *
     * @param val a new value
     */
    public void put(T val) {
        if(val.compareTo(max) > 0)
            max = val;
    }

    public T getMax() {
        return max;
    }
}

[aquariusmaster]

Suppose we have next classes:

class A implements Comparable<A>
class B extends A

With MaxHolder<T extends Comparable< T >> you will not be able to put B in MaxHolder, because B does not implement Comparable<B>, it implements Comparable<A>.
By using MaxHolder<T extends Comparable<? super T>> you can do that because MaxHolder will accept Comparable<A>.
May be useful: https://stackoverflow.com/a/25783345

[homosapi3n]

That makes sense. Thanks for clarifying