Android : notifyDataSetChanged() causes IndexOutOfBoundsException

Here's a shortened version of my code.

public class MainActivity extends ActionBarActivity {

private ArrayList<String> entry = new ArrayList<String>();
private String[] entryString = new String[11];
private ArrayAdapter<String> aa;
private ListView entryListView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    entryListView = (ListView) findViewById(R.id.listView1);
    int listID = R.layout.entry_layout;
    aa = new EntryAdapter(this, listID, entry);
    entryListView.setAdapter(aa);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    switch (id) {
    case R.id.action_add: {
        Intent intent = new Intent(MainActivity.this, AddActivity.class);
        startActivityForResult(intent, 1);
        break;
    }
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onActivityResult(int rc, int resc, Intent i) {
    super.onActivityResult(rc, resc, i);
    entryString = i.getStringArrayExtra("Entry");
    this.onNewItemAdded(entryString);
}

public void onNewItemAdded(String[] _entry){
    String key = new 
    key = _entry[0];
    entry.add(key);
    aa.notifyDataSetChanged();   //Runs without crashing when this is removed.
}

The adapter class is,

@SuppressLint("Instantiatable")
public class EntryAdapter extends ArrayAdapter<String>{

private ArrayList<String> entries;
int count;
int resource;
public EntryAdapter(Context _context, int _resource, List<String> _entries){
    //TODO Auto-generated constructor stub
    super(_context, _resource, R.id.key, _entries);
    this.resource = _resource;
    this.entries = new ArrayList<String>(_entries);
    this.count = 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;

    if (convertView == null) {
        String inflater = Context.LAYOUT_INFLATER_SERVICE;
        LayoutInflater li;
        li = (LayoutInflater) getContext().getSystemService(inflater);
        row = li.inflate(resource, parent, false);
    }

    TextView keyView = (TextView) row.findViewById(R.id.key);
    TextView siteView = (TextView) row.findViewById(R.id.site);

    for(int c=0; c<11; c++){
        while(!entries.get(c).toString().equals("")){
            count++;
        }
    }

    keyView.setText(entries.get(position));
    siteView.setText(count + "sources");

    return row;
}
} 

By commenting the aa.notifyDataSetChanged() call in the MainActivity, the application runs without crashing but throws an

IndexOutOfBoundsException: Invalid index 0, size is 0

when it is not commented.

PS: The XML is perfectly fine.