Map<String,String> map = new HashMap<String,String>();
map.put("1", "a");
map.put("2", "b");
map.put("3", "c");
map.put("4", "d");
map.put("5", "e");
Set set=map.entrySet();
Iterator it=set.iterator();
while(it.hasNext()) {
   Map.Entry entry=(Map.Entry)it.next();
   if(entry.getValue().equals("a")) {
     System.out.println(entry.getKey());
   }
   if(entry.getValue().equals("b")){
        System.out.println(entry.getKey());
   }
   if(entry.getValue().equals("c")){
        System.out.println(entry.getKey());
   }
}