Collection<customObject> list = new ArrayList<customObject>();

Collection list = new ArrayList();
Comparator comparator = new new Comparator<CustomObject>() {
    public int compare(CustomObject c1, CustomObject c2) {
        return c2.getId() - c1.getId(); // use your logic
    }
};

Collections.sort(list, comparator); // use the comparator as much as u want
System.out.println(list);

public class CustomComparator implements Comparator<CustomObject>
{
    @Override
    public int compare(CustomObject o1, CustomObject o2) {
        return o1.getId().compareTo(o2.getId());
    }
}

Collections.sort(list, new CustomComparator());

Collections.sort(allMatching, new Comparator<ClassOne>() {
  @Override public int compare(final ClassOne o1, final ClassOne o2) {
    if (o1.getMethodToSort() > o2.getMethodToSort()) {
      return 1;
    } else if (o1.getMethodToSort() < o2.getMethodToSort()) {
      return -1;
    }
    return 0;
  }
});