ArrayList<String> name = new ArrayList<String>();
name.add("Mg Mg");
name.add("Su Su");
name.add("Zaw Zaw");
name.add("Kyaw Kyaw");
name.add("Mya Mya");
ArrayList<String> items = new ArrayList<String>();
items.add("Iphone");
items.add("mp3");
items.add("tv ");
items.add("Iphone4");
items.add("Iphone5");
int rand = (int) (Math.random() * 5);
Every time you have to generate Random number, you have to save rand number into DB/file. And check that new generated no is in file or not. If it is not there then use that number for mapping and it is there then generate again the number.