import java.util.ArrayList; public class Main { public void trace(Object o) { System.out.println("Object: "+o.getClass().getName()); } public void trace(Integer i) { System.out.println("Integer"); } public void trace(Float f) { System.out.println("Float"); } public static void main(String[] args) { ArrayList objects = new ArrayList(); objects.add("toto"); objects.add(1); objects.add(2.3f); Main main = new Main(); for (Object o : objects) { main.trace(o); } } }