NullPointerException while parsing through a HashMap

Question

I am trying to parse through a HashMap stored into an ArrayList (Not good at it). I did as I have been told however, I am getting an NullPointerException

Here is my code:

private void populateList() {
    list = new ArrayList<HashMap>();

    HashMap temp = new HashMap();
    temp.put(CODE,"128");
    temp.put(SERVICE_CODE, "NRS");
    temp.put(SERVICE_GROUP, "Medical Treatment Loan");
    temp.put(SERVICE, "Number of referral slip");
    list.add(temp);

    HashMap temp1 = new HashMap();
    temp1.put(CODE,"128");
    temp1.put(SERVICE_CODE, "NL");
    temp1.put(SERVICE_GROUP, "Medical Treatment Loan");
    temp1.put(SERVICE, "Number of Loan");
    list.add(temp1);


    HashMap temp3 = new HashMap();
    temp3.put(CODE,"128");
    temp3.put(SERVICE_CODE, "AD");
    temp3.put(SERVICE_GROUP, "Medical Treatment Loan");
    temp3.put(SERVICE, "Amount disbursed");
    list.add(temp3);
}

and here is how I was trying to Iterate through my list:

for (int a =0; a < list.size();a++)
                {
                    HashMap<String, Integer> tmpData = (HashMap<String, Integer>) list.get(a);
                    Set<String> key = tmpData.keySet();
                    Iterator it = key.iterator();

                    while (it.hasNext()) {

                        String code = ""+tmpData.get(CODE); 
                        String service, service_group;

                        if(code.equalsIgnoreCase("128"))
                        {
                             if(tmpData.get("SERVICE_CODE").toString().equalsIgnoreCase("AD"))
                            {
                                service = tmpData.get("SERVICE").toString();
                                service_group = tmpData.get("SERVICE_GROUP").toString();
                                tv.setText("code >> "+code + "\nService Code >> "+tmpData.get("SERVICE_CODE").toString()
                                +"\nservice >> "+service+"\nservice_group >> "+service_group);
                            }
                        }
                        it.remove(); // avoids a ConcurrentModificationException
                    }

                }

My Error:

 12-04 19:30:22.887 24861-24861/com.example.monkey.mysql_dump E/AndroidRuntime: java.lang.NullPointerException
 12-04 19:30:22.887 24861-24861/com.example.monkey.mysql_dump E/AndroidRuntime:     at com.example.monkey.mysql_dump.input_taking$2.onClick(input_taking.java:74)

Basically I am trying to get the last value here, just to see if I can actually go through the whole arrayList. Thank you.