public class Caja {
private Object dato;
public Caja() { super(); }
public Object dame() {
return dato;
}
public void pon(Object x) {
dato = x;
}
}
public static void main(String args[]) {
Caja c = new Caja();
c.pon(“Hola”);
Integer n = (Integer) c.dame();
}
public class Caja <T> {
private T dato;
public Caja() { super(); }
public T dame() { return dato; }
public void pon(T x) { dato = x; }
}
Caja <Integer> c;
public class TestCaja {
public static void main(String args[]) {
Caja <Integer> c = new Caja <Integer> ();
c.pon(new Integer(46));
Integer n = c.dame();
}
}
Caja <Integer> c;
public static void main(String args[]) {
Caja <String> c = new Caja <String> ();
c.pon(“Hola”);
Integer n = c.dame();
}
public static <T> void mostrarArray(ArrayList<T> a) {
for (int i = 0; i < a.size(); i++)
System.out.println(a.get(i).toString());
}
public interface Comparable<T> {
public int compareTo(T x);
// Devuelve < 0 , si this < x
// Devuelve > 0 , si this > x
// Devuelve == 0 , si this == x
}
public abstract class Figura implements Comparable<Figura> {
…
public int compareTo(Figura f) {
if (this.area() < f.area()) return -1;
else if (this.area() > f.area()) return 1;
else return 0;
}
…