Confusing Mockito behavior with overriding interfaces

OddMockitoStuffTest.java

package com.kenshoo.rtb.tools;

import org.junit.Test;

import static junit.framework.Assert.assertTrue;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

/**
 * Created by IntelliJ IDEA.
 * User: tzachz
 * Date: 9/24/13
 */
public class OddMockitoStuffTest {

    private static final Long INPUT = 3l;

    interface Parent<T> {
        boolean apply(T input);
    }

    interface Child extends Parent<Long> {
        @Override
        public boolean apply(Long input);
    }

    interface EmptyChild extends Parent<Long> {}

    @Test
    public void mockAndRunChildSucceeds() throws Exception {
        Child mock = mock(Child.class);
        when(mock.apply(INPUT)).thenReturn(true);
        boolean result = mock.apply(INPUT);
        assertTrue(result);
    }

    @Test
    public void mockChildAndRunParentFails() throws Exception {
        Child mock = mock(Child.class);
        when(mock.apply(INPUT)).thenReturn(true);
        // This is what happens explicitly in Collections2.filter -
        // it executes the parent's apply(Object) and not the child's apply(Long)
        boolean result = ((Parent<Long>)mock).apply(INPUT);
        // this fails!
        assertTrue(result);
    }

    @Test
    public void ifChildEmptyItsOK() throws Exception {
        EmptyChild mock = mock(EmptyChild.class);
        when(mock.apply(INPUT)).thenReturn(true);
        // there's only the parent's method to mock and run, so this passes
        boolean result = ((Parent<Long>)mock).apply(INPUT);
        assertTrue(result);
    }
}