You are using Lists, concrete ArrayList. ArrayList also implements Collection interface. Collection interface has sort method which is used to sort the elements present in the specified list of Collection in ascending order. This will be the quickest and possibly the best way for your case.
Sorting a list in ascending order can be performed as default operation on this way:
Collections.sort(list);
Sorting a list in descending order can be performed on this way:
Collections.reverse(list);
According to these facts, your solution has to be written like this:
public class tes
{
public static void main(String args[])
{
List<Integer> lList = new ArrayList<Integer>();
lList.add(4);
lList.add(1);
lList.add(7);
lList.add(2);
lList.add(9);
lList.add(1);
lList.add(5);
Collections.sort(lList);
for(int i=0; i<lList.size();i++ )
{
System.out.println(lList.get(i));
}
}
}
More about Collections you can read here.