Hashtable<Integer, String> hashtable = new Hashtable<>();
        hashtable.put(1, "ssss");
        hashtable.put(1, "dddd");
        hashtable.put(2, "ssss");
        //hashtable.put(null,"sdsdsd");
        //hashtable.put(3,null);
        for (int i = 0; i < hashtable.size(); i++) {
            Log.d(EvidenceActivity.class.getName(), "hashtable:" + hashtable.get(i + 1));
        }
        // get values using enumeration
        Enumeration<Integer>  enumerationKeys = hashtable.keys();
        while(enumerationKeys.hasMoreElements())
        {
            Integer key = enumerationKeys.nextElement();
            String value = hashtable.get(key);
            if(key == 1)
            {
                hashtable.remove(key);  // can delete using enumeration too .... then
                //difference between iterator and enumeration
            }
            Log.d(EvidenceActivity.class.getName(), "key:"+key);
            Log.d(EvidenceActivity.class.getName(), "value:"+value);
        }
        Log.d(EvidenceActivity.class.getName(), "hashtable size after deletion:" + hashtable.size());