[Java] Cloneableな可変オブジェクトのListのディープコピー

ListDeepCopyTest.java

import org.apache.commons.lang3.ObjectUtils;
private <E extends Cloneable> List<E> copyDeep(List<? extends E> src) {
  List<E> dest = new ArrayList<E>();
  for (E item : src) {
    dest.add(ObjectUtils.clone(item));
  }
  return dest;
}

@Test
public void testCopyDeepDate() throws ParseException {
  DateFormat df = new SimpleDateFormat("yyyy/MM/dd");
  List<Date> src = new ArrayList<Date>();
  src.add(df.parse("2012/03/08"));
  src.add(df.parse("2012/03/09"));
  src.add(null);

  List<Date> dest = copyDeep(src);
  src.get(0).setTime(new Date().getTime());
  src.get(1).setTime(new Date().getTime());

  assertEquals(df.parse("2012/03/08"), dest.get(0));
  assertEquals(df.parse("2012/03/09"), dest.get(1));
  assertNull(dest.get(2));
}

@Test
public void testCopyDeepSubDate() throws ParseException {
  List<SubDate> src = new ArrayList<SubDate>();
  src.add(new SubDate("2012/03/08"));

  List<Date> dest = this.<Date>copyDeep(src);
  src.get(0).setTime(new Date().getTime());

  assertEquals(new SubDate("2012/03/08"), dest.get(0));
}

private static class SubDate extends Date {
  private static final long serialVersionUID = 1L;
  public SubDate(String string) throws ParseException {
    DateFormat df = new SimpleDateFormat("yyyy/MM/dd");
    setTime(df.parse(string).getTime());
  }
}