how to remove arraylist duplicate values

Question

I am performing some maintenance tasks on an old system. I have an arraylist that contains following values:

a,b,12
c,d,3
b,a,12
d,e,3
a,b,12

Answer 1

Assuming the entries are String. Then you can sort each of the entry and then do the duplicate check. Then you can store the entry in a map and use the contains(key) to see if they exist.

EDIT: added a complete code example.

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Test test = new Test();
        List someList = new ArrayList(); 
        someList.add("d,e,3");
        someList.add("a,b,12");
        someList.add("c,d,3");
        someList.add("b,a,12");
        someList.add("a,b,12");
            //using a TreeMap since you care about the order
        Map dupMap = new TreeMap();
        String key = null;
        for(String some:someList){
            key = test.sort(some);
            if(key!=null && key.trim().length()>0 && !dupMap.containsKey(key)){
                dupMap.put(key, some);
            }
        }
        List uniqueList = new ArrayList(dupMap.values());
        for(String unique:uniqueList){
            System.out.println(unique);
        }

    }
    private String sort(String key) {
      if(key!=null && key.trim().length()>0){
        char[] keys = key.toCharArray();
        Arrays.sort(keys);
        return String.valueOf(keys);
      }
      return null;
   }
}

Prints:

a,b,12

c,d,3

d,e,3