The Java collection collection-list-arraylist removes duplicate elements from the ArrayList collection.

ImportJava.util.*;/*removes duplicate elements from the ArrayList collection. */classArraylisttest { Public Static voidsop (Object obj) {System.out.println (obj); }     Public Static voidMain (string[] args) {ArrayList Al=NewArrayList (); Al.add ("Java01"); Al.add ("Java02"); Al.add ("Java01"); Al.add ("Java02"); Al.add ("Java01");//Al.add ("java03");        /*the next call in the loop in the iteration is hasnext judged once.        Iterator it = Al.iterator ();        while (It.hasnext ()) {SOP (It.next () + "...." +it.next ()); }        */        /**/SOP (AL);        Al = Singleelement (AL);            SOP (AL);        } public static ArrayList singleelement (ArrayList al) {//defines a temporary container.        ArrayList Newal = new ArrayList ();        Iterator it = Al.iterator ();            while (It.hasnext ()) {Object obj = It.next ();        if (!newal.contains (obj)) newal.add (obj);    } return Newal; }}

The Java collection collection-list-arraylist removes duplicate elements from the ArrayList collection.