Android : App works on emulator but doesn't when installed manually on device

I developed a small app which makes an http GET call to fetch some data from my data store. It all went hunky dory when I tested it on emulator, but as soon I generated an apk and installed it on my device, it broke. The app starts up all right, but nothing shows up on screen. I am assuming the problem is with making calls to my data store here. This is the piece of code where I make call -

public <T> T Get(String url, List<NameValuePair> params, final Class<T> objectClass) {
    DefaultHttpClient defaultHttpClient = new DefaultHttpClient();
    String paramString = URLEncodedUtils.format(params, "utf-8");
    url += "?" + paramString;
    HttpGet httpGet = new HttpGet(url);
    try {

        httpGet.setHeader("Accept", "application/json");
        httpGet.setHeader("Accept-Encoding", "gzip");

        HttpResponse httpResponse = defaultHttpClient.execute(httpGet);

        HttpEntity httpEntity = httpResponse.getEntity();
        if (httpEntity != null) {
            InputStream inputStream = httpEntity.getContent();
            Header contentEncoding = httpResponse.getFirstHeader("Content-Encoding");
            if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) {
                inputStream = new GZIPInputStream(inputStream);
            }

            String resultString = convertStreamToString(inputStream); // final json string response object
            inputStream.close();

            if(resultString.length() == 3) // temp for empty -- {}\n
            {
                // done for proper deserialization
                resultString = "[]";
            }

            return new GsonBuilder().create().fromJson(resultString, objectClass);

        }

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
    } catch (ClientProtocolException e) {
        e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
    } catch (IOException e) {
        e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
    }
    return null;
}

AndroidManifest.xml -- just in case

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="org.compani.proj"
    android:versionCode="1"
    android:versionName="1.0">

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="22" />

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" 
        android:name="Applicate">
        <activity
            android:name="org.compani.proj.MainActivity"
            android:label="@string/app_name"
            android:launchMode="singleInstance">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>

I am guessing that might be the problem. How can I fix this? Are there better methods to debug the app when installed in the devie anyways?

I am targeting API 22 and my device is Nexus 5 running Android 5.1.1