Something

public interface Foo {   myMethod();}public class Parent() {}public class Child1 extends Base implements Foo {   public myMethod() {   }}ArrayList<Parent> myList = new ArrayList<Parent>();myList.add(new Child1());myList.add(new Child2());myList.add(new Child3());myList.get(0).myMethod();   // Ayto edw den doyleyei, giati to MyList.get(0) epistrefei                            // typo Parent, enw thn methodA() thn ekane implement to ChildX