ArrayList sorting using Ccomparator

[rakeshdec kumar]

ArrayList al=new ArrayList();

al.add("ram");
al.add("xyz");
al.add(11);
al.add(55);
al.add("25");


How to implement Comparator for this list to sort elements

[Ravishanker kumar]

Here you are using different type of objects(String,Integer) into list.
Please use generic for collection.In this particular case,you can use natural order for string as below,

List al=new ArrayList();
al.add("ram");
al.add("xyz");
al.add("11");
al.add("55");
al.add("25");
System.out.println("Before sorting:"+al);
Collections.sort(al);
System.out.println("After Sorting:"+al);

[rakeshdec kumar]

how to sort different types of objects

[Stephan van Hulst]

You first need to decide how two different objects compare, before you can sort them. How do 11 and "abc" compare, for instance?

If you want lexicographical sorting, you can do something like this:

Comparator<Object> lexicographically = new Comparator<Object>() {

  public int compare(Object o1, Object o2) {
    return o1.toString().compareTo(o2.toString());
  }
};

List<?> list = Arrays.asList("ram", "xyz", 11, 55, "25");
Collections.sort(list, lexicographically);

System.out.println(list);

[rakeshdec kumar]

thank you