getting Nulpointer in xml file parsing

[shawn peter]

this is my main activity

package com.android.testservice;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONObject;
import org.w3c.dom.CharacterData;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

import android.os.Bundle;
import android.os.StrictMode;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {
	String readTwitterFeed;

	@Override
	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);
		try {
			StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
					.permitAll().build();
			StrictMode.setThreadPolicy(policy);

			TextView t = (TextView) findViewById(R.id.textView1);
			setContentView(R.layout.activity_main);
			readTwitterFeed = readTwitterFeed();
			// t.setText(readTwitterFeed);
			parse(readTwitterFeed);
		} catch (Exception e) {
			e.printStackTrace();
		}
		// JSONObject xmlJSONObj = XML.toJSONObject(readTwitterFeed);
		// String jsonPrettyPrintString =
		// xmlJSONObj.toString(PRETTY_PRINT_INDENT_FACTOR);
		// System.out.println(jsonPrettyPrintString);

		// t.setText(json.toString(2));
		try {
			JSONArray jsonArray = new JSONArray(readTwitterFeed);
			Log.i(MainActivity.class.getName(), "Number of entries "
					+ jsonArray.length());
			for (int i = 0; i < jsonArray.length(); i++) {
				JSONObject jsonObject = jsonArray.getJSONObject(i);
				Log.i(MainActivity.class.getName(),
						jsonObject.getString("text"));
			}
		} catch (Exception e) {
			e.printStackTrace();
		}

	}

	public void parse(String xmlRecords) {
		try {
			DocumentBuilder db = DocumentBuilderFactory.newInstance()
					.newDocumentBuilder();
			InputSource is = new InputSource();
			is.setCharacterStream(new StringReader(xmlRecords));

			Document doc = db.parse(is);
			NodeList nodes = doc.getElementsByTagName("empno");

			for (int i = 0; i < nodes.getLength(); i++) {
				Element element = (Element) nodes.item(i);

				NodeList name = element.getElementsByTagName("Username");
				Element line = (Element) name.item(0);
				String n = getCharacterDataFromElement(line);

				System.out.println("name : " + name);

				NodeList title = element.getElementsByTagName("Password");
				line = (Element) title.item(0);
				String t = getCharacterDataFromElement(line);
				System.out.println("marks : " + t);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static String getCharacterDataFromElement(Element e) {
		Node child = e.getFirstChild();
		try {
			if (child instanceof CharacterData) {
				CharacterData cd = (CharacterData) child;
				return cd.getData();
			}
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return "";
	}

	public String readTwitterFeed() {
		StringBuilder builder = new StringBuilder();
		HttpClient client = new DefaultHttpClient();
		HttpGet httpGet = new HttpGet(
				"http://172.22.221.104:9763/services/CitiService.HTTPEndpoint/LoginDetails");
		try {
			HttpResponse response = client.execute(httpGet);
			StatusLine statusLine = response.getStatusLine();
			int statusCode = statusLine.getStatusCode();
			if (statusCode == 200) {
				HttpEntity entity = response.getEntity();
				InputStream content = entity.getContent();
				BufferedReader reader = new BufferedReader(
						new InputStreamReader(content));
				String line;
				while ((line = reader.readLine()) != null) {
					builder.append(line);
				}
			} else {
				Log.e(MainActivity.class.toString(), "Failed to download file");
			}
		} catch (ClientProtocolException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return builder.toString();
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

i am getting nullpointer exception at below line.

String n = getCharacterDataFromElement(line);

below is the xml my file

- <Entries xmlns="http://ws.wso2.org/dataservice">
+ <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">10266</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Harsha</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx$</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">5003131</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Shamal</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">5003430</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Amila</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">5003443</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Sameera</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">5003510</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Lakindu</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">5003511</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Nazeeha</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">5006510</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Harsha</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">10266</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Chamidu</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">8000122</empno> 
  <Username xmlns="http://ws.wso2.org/dataservice">Shyama</Username> 
  <Password xmlns="http://ws.wso2.org/dataservice">1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno xmlns="http://ws.wso2.org/dataservice">8000163</empno> 
  <Username>Randima</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8000254</empno> 
  <Username>Ranga</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8001589</empno> 
  <Username>Hasaral</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8001638</empno> 
  <Username>Niranjan</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8002064</empno> 
  <Username>Dinithi</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8002608</empno> 
  <Username>Chathuranaga</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8002754</empno> 
  <Username>Ishani</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8003577</empno> 
  <Username>Chamara</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
- <Entry>
  <empno>8003578</empno> 
  <Username>Mihidu</Username> 
  <Password>1qaz2wsx@</Password> 
  </Entry>
  </Entries>

i am getting whole xml file in below line

readTwitterFeed = readTwitterFeed();

[Steve Luke]

sam liyanage wrote:i am getting nullpointer exception at below line.

String n = getCharacterDataFromElement(line);

Past the actual stack trace. A null pointer exception always happens for the same reason: a variable you are dereferencing on a line doesn't point to an Object. You are not dereferencing any variables on that line, so that line can not be the line actually causing the exception.

[shawn peter]

Thanks Steve.Problem solve now.