Develop Reference

PJSUA2 Android - Incoming calls drop after 32 seconds

I'm building a PJSUA2 (PJSIP 2.8) Android app and I have some issues: i.e. only on incoming call, call state remains in "PJSIP_INV_STATE_CONNECTING" and after 32 seconds the call drops.
I'm looking for the cause of the issue since several days, I googled a lot and all what I found is: in most situations this issue is related to NAT management or network issues related to NAT. In a few words: in most cases the called party does not receive the ACK after answering the call.
Finally I was able to log all SIP messages between my app and the SIP server and found that my app receives the ACK from the server, so I suppose it's not a network related issue.
I compiled PJSIP 2.8 with OpenSSL and SRTP support, but without video support (I don't need it at least at the moment). If it makes any difference, the app has a target version 28 and minimum SDK version 19.
I tried several apps on the market and they work fine enough with and without SRTP and with all signaling transports (UDP, TCP, TLS), WebRTC works fine too (tested with SipML5), so I would exclude a server misconfiguration. My app does the same (except SRTP with which I have some issues at the moment).
I tried with a SIP provider too (MessageNet) using UDP and the behaviour is always the same. I tried to use compact SIP messages and it behaves the same, with and without uri parameters, with and without STUN and or ICE and nothing changes. Mobile network and WiFi networks give the same results.
I tried to debug inside PJSIP library too, but without any success, then I tried to follow the code, to understand what I was doing wrong, but it doesn't seem to me there is something evidently wrong.
The following is the code (last version) which initializes PJSIP:
public class SipService extends Service {
private Looper serviceLooper;
private ServiceHandler serviceHandler;
private final Messenger mMessenger = new Messenger(new IncomingHandler());
private LocalBroadcastManager localBroadcast;
private LifecycleBroadcastReceiver lifecycleBroadcastReceiver;
private boolean lastCheckConnected;
private Endpoint endpoint;
private LogWriter logWriter;
private EpConfig epConfig;
private final List<ManagedSipAccount> accounts = new ArrayList<>();
private final Map<String, Messenger> eventRegistrations = new HashMap<>();
#TargetApi(Build.VERSION_CODES.N)
#Override
public void onCreate() {
super.onCreate();
String userAgent = "MyApp";
try {
PackageInfo pInfo = getPackageManager().getPackageInfo(getPackageName(), 0);
String appLabel = (pInfo.applicationInfo.labelRes == 0 ? pInfo.applicationInfo.nonLocalizedLabel.toString() : getString(pInfo.applicationInfo.labelRes));
userAgent = appLabel + "/" + pInfo.versionName;
} catch (PackageManager.NameNotFoundException e) {
Log.e("SipService", "Unable to get app version", e);
}
try {
endpoint = new MyAppEndpoint();
endpoint.libCreate();
epConfig = new EpConfig();
// Logging
logWriter = new PJSIPToAndroidLogWriter();
epConfig.getLogConfig().setWriter(logWriter);
epConfig.getLogConfig().setLevel(5);
// UA
epConfig.getUaConfig().setMaxCalls(4);
epConfig.getUaConfig().setUserAgent(userAgent);
// STUN
StringVector stunServer = new StringVector();
stunServer.add("stun.pjsip.org");
epConfig.getUaConfig().setStunServer(stunServer);
// General Media
epConfig.getMedConfig().setSndClockRate(16000);
endpoint.libInit(epConfig);
// UDP transport
TransportConfig udpCfg = new TransportConfig();
udpCfg.setQosType(pj_qos_type.PJ_QOS_TYPE_VOICE);
endpoint.transportCreate(pjsip_transport_type_e.PJSIP_TRANSPORT_UDP, udpCfg);
// TCP transport
TransportConfig tcpCfg = new TransportConfig();
//tcpCfg.setPort(5060);
endpoint.transportCreate(pjsip_transport_type_e.PJSIP_TRANSPORT_TCP, tcpCfg);
// TLS transport
TransportConfig tlsCfg = new TransportConfig();
endpoint.transportCreate(pjsip_transport_type_e.PJSIP_TRANSPORT_TLS, tlsCfg);
endpoint.libStart();
} catch (Exception e) {
throw new RuntimeException("Unable to initialize and start PJSIP", e);
}
ConnectivityManager cm = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
lastCheckConnected = activeNetwork != null && activeNetwork.isConnected();
updateForegroundNotification();
startForeground(MyAppConstants.N_FOREGROUND_NOTIFICATION_ID, buildForegroundNotification());
localBroadcast = LocalBroadcastManager.getInstance(this);
HandlerThread thread = new HandlerThread("ServiceStartArguments",
Process.THREAD_PRIORITY_BACKGROUND);
thread.start();
// Get the HandlerThread's Looper and use it for our Handler
serviceLooper = thread.getLooper();
serviceHandler = new ServiceHandler(serviceLooper);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
// Register LifeCycleBroadcastReceiver to receive network change notification
// It seems it's mandatory to do it programmatically since Android N (24)
lifecycleBroadcastReceiver = new LifecycleBroadcastReceiver();
IntentFilter intentFilter = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
registerReceiver(lifecycleBroadcastReceiver, intentFilter);
}
// Initialization
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
if (prefs != null) {
try {
CodecInfoVector codecs = endpoint.codecEnum();
SharedPreferences.Editor editor = prefs.edit();
for (int i = 0; i < codecs.size(); i++) {
CodecInfo codec = codecs.get(i);
int priority = prefs.getInt("codecs.audio{" + codec.getCodecId() + "}", 0);
try {
endpoint.codecSetPriority(codec.getCodecId(), (short) priority);
codec.setPriority((short) priority);
} catch (Exception e) {
Log.e("SipService", "Unexpected error setting codec priority for codec " + codec.getCodecId(), e);
}
}
} catch (Exception e) {
Log.e("SipService", "Unexpected error loading codecs priorities", e);
}
}
}
#Override
public void onDestroy() {
for (Account acc : accounts) {
acc.delete();
}
accounts.clear();
try {
endpoint.libDestroy();
} catch (Exception e) {
e.printStackTrace();
}
endpoint.delete();
endpoint = null;
epConfig = null;
if (lifecycleBroadcastReceiver != null) {
unregisterReceiver(lifecycleBroadcastReceiver);
}
super.onDestroy();
}
.......
}
And the following is my Account class with creation and registration code:
public class ManagedSipAccount extends Account {
public final String TAG;
private final VoipAccount account;
private final PhoneAccountHandle handle;
private final SipService service;
private final AccountStatus status;
private final Map<Integer, VoipCall> calls = new HashMap<>();
private final Map<String, VoipBuddy> buddies = new HashMap<>();
private AccountConfig acfg;
private List<SrtpCrypto> srtpCryptos = new ArrayList<>();
private AuthCredInfo authCredInfo;
public ManagedSipAccount(SipService service, VoipAccount account, PhoneAccountHandle handle) {
super();
TAG = "ManagedSipAccount/" + account.getId();
this.service = service;
this.account = account;
this.handle = handle;
this.status = new AccountStatus(account.getUserName() + "#" + account.getHost());
acfg = new AccountConfig();
}
public void register(Map<String, String> contactParameters) throws Exception {
StringBuilder contactBuilder = new StringBuilder();
for (Map.Entry<String, String> entry : contactParameters.entrySet()) {
contactBuilder.append(';');
contactBuilder.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
contactBuilder.append("=\"");
contactBuilder.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
contactBuilder.append("\"");
}
StringBuilder logBuilder = new StringBuilder();
logBuilder.append("Registering: ");
logBuilder.append(account.getProtocol().name());
/*logBuilder.append('(');
logBuilder.append(service.getTransport(account.getProtocol()));
logBuilder.append(')');*/
if (account.isEncryptionSRTP()) {
logBuilder.append(" SRTP");
}
if (account.isIce()) {
logBuilder.append(" ICE");
}
Log.d(TAG, logBuilder.toString());
String idUri = "sip:" + account.getUserName();
if (!"*".equals(account.getRealm())) {
idUri += "#" + account.getRealm();
}
else {
idUri += "#127.0.0.1" /*+ account.getHost()*/;
}
acfg.setIdUri(idUri);
acfg.getRegConfig().setRegistrarUri("sip:" + account.getHost() + ":" + account.getPort() + ";transport=" + account.getProtocol().name().toLowerCase());
acfg.getRegConfig().setRetryIntervalSec(account.getRetryInterval());
acfg.getRegConfig().setRegisterOnAdd(false);
acfg.getSipConfig().setContactUriParams(contactBuilder.toString());
// NAT management
acfg.getNatConfig().setSipStunUse(pjsua_stun_use.PJSUA_STUN_USE_DEFAULT);
if (account.isIce()) {
acfg.getNatConfig().setIceEnabled(true);
acfg.getNatConfig().setIceAlwaysUpdate(true);
acfg.getNatConfig().setIceAggressiveNomination(true);
}
else {
acfg.getNatConfig().setSdpNatRewriteUse(1);
}
acfg.getMediaConfig().getTransportConfig().setQosType(pj_qos_type.PJ_QOS_TYPE_VOICE);
if (account.isEncryptionSRTP()) {
acfg.getMediaConfig().setSrtpUse(pjmedia_srtp_use.PJMEDIA_SRTP_MANDATORY);
acfg.getMediaConfig().setSrtpSecureSignaling(0);
//acfg.getMediaConfig().getSrtpOpt().setKeyings(new IntVector(2));
acfg.getMediaConfig().getSrtpOpt().getKeyings().clear();
acfg.getMediaConfig().getSrtpOpt().getKeyings().add(pjmedia_srtp_keying_method.PJMEDIA_SRTP_KEYING_SDES.swigValue());
acfg.getMediaConfig().getSrtpOpt().getKeyings().add(pjmedia_srtp_keying_method.PJMEDIA_SRTP_KEYING_DTLS_SRTP.swigValue());
acfg.getMediaConfig().getSrtpOpt().getCryptos().clear();
StringVector cryptos = Endpoint.instance().srtpCryptoEnum();
for (int i = 0; i < cryptos.size(); i++) {
SrtpCrypto crypto = new SrtpCrypto();
crypto.setName(cryptos.get(i));
crypto.setFlags(0);
srtpCryptos.add(crypto);
acfg.getMediaConfig().getSrtpOpt().getCryptos().add(crypto);
}
}
else {
acfg.getMediaConfig().setSrtpUse(pjmedia_srtp_use.PJMEDIA_SRTP_DISABLED);
acfg.getMediaConfig().setSrtpSecureSignaling(0);
}
authCredInfo = new AuthCredInfo("digest",
account.getRealm(),
account.getAuthenticationId() != null && account.getAuthenticationId().trim().length() > 0 ? account.getAuthenticationId() : account.getUserName(),
0,
account.getPassword());
acfg.getSipConfig().getAuthCreds().add( authCredInfo );
acfg.getIpChangeConfig().setHangupCalls(false);
acfg.getIpChangeConfig().setShutdownTp(true);
create(acfg);
ConnectivityManager cm = (ConnectivityManager)service.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null && activeNetwork.isConnected();
if (isConnected) {
setRegistration(true);
}
}
#Override
public void onRegStarted(OnRegStartedParam prm) {
super.onRegStarted(prm);
Log.d(TAG, "Status: Registering...");
status.setStatus(AccountStatus.Status.REGISTERING);
service.updateStatus(this);
}
#Override
public void onRegState(OnRegStateParam prm) {
super.onRegState(prm);
try {
Log.d(TAG, "Registration state: " + prm.getCode().swigValue() + " " + prm.getReason());
AccountInfo ai = getInfo();
status.setStatus(ai.getRegIsActive() ? AccountStatus.Status.REGISTERED : AccountStatus.Status.UNREGISTERED);
Log.d(TAG, "Status: " + status.getStatus().name() + " " + super.getInfo().getUri());
service.updateStatus(this);
} catch (Exception e) {
e.printStackTrace();
}
}
.....
}
Finally, how I answer the code at the moment in a class which extends the PJSIP's Call class:
#Override
public void answerCall() {
Log.d(TAG, "Answering call...");
CallOpParam prm = new CallOpParam(true);
prm.setStatusCode(pjsip_status_code.PJSIP_SC_OK);
prm.getOpt().setAudioCount(1);
prm.getOpt().setVideoCount(0);
try {
this.answer(prm);
} catch (Exception e) {
e.printStackTrace();
}
}
I also tried with new CallOpParam(); with just the status code and nothing else, but nothing changes.
One note: I created the IdUri as sip:username#127.0.0.1 because without the host the resulting contact was and I thought that the missing user part may be the cause of the issue or part of it.
The following is the trace of the app <-> my Asterisk server communication during call (linked because of content length exceed).
https://gist.github.com/ivano85/a212ddc9a808f3cd991234725c2bdb45
The ServerIp is an internet public IP, while the MyIp[5.XXX.XXX.XXX] is my phone's public IP.
As you can see from the log, my app sends a 100 Trying, then a 180 Ringing when the phone rings, then the user answers and the app sends a 200 OK. The server replies with a ACK message (I would say it's not a NAT issue, because PJSIP receives the ACK). I see the same from Asterisk.
After this I would expect the call goes from PJSIP_INV_STATE_CONNECTING to PJSIP_INV_STATE_CONFIRMED, but it does not happen, so PJSIP continues to send a 200 OK and receive the ACK every about 2 seconds, until the call times out after 32 seconds and PJSIP disconnects the call (sending a BYE).
I'm starting to think that PJSIP just ignores ACK messages and just has a wrong behaviour. Please help me to understand what is happening here. I would appreciate it so much!
Obviously let me know if you think that more details are needed.

Android Retrofit Request Using AWS Signature Authorization

I'm trying to get data from the API which needs to handle aws-authentication, my question is how can I generate Authorization and X-Amz-Date?
I have to pass 3 parameter as header: Content-Type, Authorization and X-Amz-Date.
As you can find in image:
here is the function that generate Authorization String:
public static String gerateOAuthAWS(Context co) throws Exception {
JodaTimeAndroid.init(co);
DateTimeFormatter fmt = DateTimeFormat.forPattern("EEE', 'dd' 'MMM' 'yyyy' 'HH:mm:ss' 'Z").withLocale(Locale.US);
String ZONE = "GMT";
DateTime dt = new DateTime();
DateTime dtLondon = dt.withZone(DateTimeZone.forID(ZONE)).plusHours(1);
String formattedDate = dtLondon.toString(fmt);
String oauth = "AWS4-HMAC-SHA256 Credential="+ ACCESS_KEY+"/us-east-1/execute-api/aws4_request, SignedHeaders=content-type;host;x-amz-date, Signature="+
getSignatureKey(SECRET_KEY,formattedDate,"us-east-1","execute-api");
return oauth;
}
static byte[] HmacSHA256(String data, byte[] key) throws Exception {
String algorithm="HmacSHA256";
Mac mac = Mac.getInstance(algorithm);
mac.init(new SecretKeySpec(key, algorithm));
return mac.doFinal(data.getBytes("UTF8"));
}
static String getSignatureKey(String key, String dateStamp, String regionName, String serviceName) throws Exception {
byte[] kSecret = ("AWS4" + key).getBytes("UTF8");
byte[] kDate = HmacSHA256(dateStamp, kSecret);
byte[] kRegion = HmacSHA256(regionName, kDate);
byte[] kService = HmacSHA256(serviceName, kRegion);
byte[] kSigning = HmacSHA256("aws4_request", kService);
return Base64.encodeToString(kSigning,Base64.DEFAULT).replaceAll("\n", "");
}
Content-Type is "application/x-www-form-urlencoded"
and generate X-Amz-Date something as: "201805138T120046Z"
then pass them through retrofit methods:
#GET("prod/video")
Call<ArrayList<Video>> getAllVideos(#Header("Content-Type")String content_type,
#Header("X-Amz-Date")String amz_date,
#Header("Authorization")String auth);
the result returns null and I'm sure the issue is related the authorization since it worked before well.
thanks for your helps :)

i always said to my friends why do you use retrofit or valley , if it's seems complicated to you !
instead you can use JSOUP or OKHTTP it's much easier and I realy love JSOUP
an example that you can connect and send you data:
private void fcmIdentity(final String fcmKey) {
new Thread(new Runnable() {
#Override
public void run() {
try {
SSLHelper.enableSSLSocket();
Connection.Response response = Jsoup
.connect(Urls.identity)
.header("Accept", "application/json")
.header("KEY_2", "VALUE_2")
.method(Connection.Method.POST)
.ignoreContentType(true)
.ignoreHttpErrors(true)
.validateTLSCertificates(true)
.followRedirects(true)
.data("fcm", "" + fcmKey)
.data("identity", preferences.getString("FCM_ID", ""))
.execute();
Log.i("fcmIdentity", response.statusCode() + "");
Log.i("fcmIdentity", response.toString());
Log.d("fcmIdentity", response.headers().toString());
Log.i("fcmIdentity", response.body());
} catch (Exception e) {
e.printStackTrace();
if (e instanceof IOException) {
G.toast(getString(R.string.connection_error), true);
}
}
}
}).start();
}
about SSLHelper it help to connect to HTTPS
for more info check my topic https://answers.uncox.com/android/question/13003

How to create and send Bye message from client to server in jainsip android?

I have tried jainsip example in Mobicents restcomm-android-sdk.Its worked for me but i am not able create bye message from client side properly.
I created a Bye Message class like this
public class Bye {
public Request MakeRequest(SipManager sipManager) throws ParseException,
InvalidArgumentException {
AddressFactory addressFactory = sipManager.addressFactory;
SipProvider sipProvider = sipManager.sipProvider;
MessageFactory messageFactory = sipManager.messageFactory;
HeaderFactory headerFactory = sipManager.headerFactory;
// Create addresses and via header for the request
Address fromAddress = addressFactory.createAddress("sip:"
+ sipManager.getSipProfile().getSipUserName() + "#"
+ sipManager.getSipProfile().getRemoteIp());
fromAddress.setDisplayName(sipManager.getSipProfile().getSipUserName());
Address toAddress = addressFactory.createAddress("sip:"
+ sipManager.getSipProfile().getSipUserName() + "#"
+ sipManager.getSipProfile().getRemoteIp());
toAddress.setDisplayName(sipManager.getSipProfile().getSipUserName());
Address contactAddress = sipManager.createContactAddress();
ArrayList<ViaHeader> viaHeaders = sipManager.createViaHeader();
URI requestURI = addressFactory.createAddress(
"sip:" + sipManager.getSipProfile().getRemoteEndpoint())
.getURI();
// Build the request
CallIdHeader callIdHeader = sipManager.sipProvider.;
final Request request = messageFactory.createRequest(requestURI,
Request.BYE, sipProvider.getNewCallId(),
headerFactory.createCSeqHeader(1l, Request.BYE),
headerFactory.createFromHeader(fromAddress, "c3ff411e"),
headerFactory.createToHeader(toAddress, null), viaHeaders,
headerFactory.createMaxForwardsHeader(70));
// Add the contact header
request.addHeader(headerFactory.createContactHeader(contactAddress));
ExpiresHeader eh = headerFactory.createExpiresHeader(300);
request.addHeader(eh);
// Print the request
System.out.println(request.toString());
return request;
// Send the request --- triggers an IOException
// sipProvider.sendRequest(request);
// ClientTransaction transaction = sipProvider
// .getNewClientTransaction(request);
// Send the request statefully, through the client transaction.
// transaction.sendRequest();
}
}
Call it From SipManager class as
public void disconnectCall() throws NotInitializedException {
// TODO Auto-generated method stub
if (!initialized)
throw new NotInitializedException("Sip Stack not initialized");
this.sipManagerState = SipManagerState.BYE;
Bye byeRequest = new Bye();
Request r=null ;
try{
r = byeRequest.MakeRequest(this);//byeRequest.MakeRequest(SipManager.this);
final ClientTransaction transaction = this.sipProvider
.getNewClientTransaction(r);
Thread thread = new Thread() {
public void run() {
try {
transaction.sendRequest();
} catch (SipException e) {
e.printStackTrace();
}
}
};
thread.start();
} catch (TransactionUnavailableException e) {
e.printStackTrace();
}catch (InvalidArgumentException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
I have got 481 error code as response.I think I have missed the current callid field in the bye message.I have searched for it but not found from sipmanager class.pls help.

Nidhin,
BYE messages are always inside a SIP dialog, so you don't have to create a new message from scratch. Instead, you just need to get ahold of the dialog you want to terminate, create a request of type BYE from that and send it. JAIN will take care of the rest.
For an example, you can check the code at the Mobicents restcomm-android-sdk repo, method sendByeClient():
https://github.com/Mobicents/restcomm-android-sdk/blob/master/sipua/src/main/java/org/mobicents/restcomm/android/sipua/impl/SipManager.java#L931
Please also keep in mind that the JAIN SIP example has been obsoleted by Messenger example that uses the Restcomm Android Client SDK which offers a simpler API. Here's its code for your reference:
https://github.com/Mobicents/restcomm-android-sdk/tree/master/Examples/restcomm-messenger

How to connect Android on RabbitMQ?

I'd like to use RabbitMQ client from an android App.
From the server side, i use SpringBoot with spring AMQP. RabbitMQ (rabbitmq_server-3.4.3) is installed correctly and an integration test valid the server behaviour.
The difficult part is when i try to create a connection from RabbitMQ connectionFactory inside my android project.
I get this exception :
failed to connect to localhost/127.0.0.1 (port 5672):
connect failed: ECONNREFUSED (Connection refused)
In android manifest, Internet permission is set :
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
Here is my code :
public class LoadingTask extends AsyncTask<String, Integer, Integer> {
private static String replyQueue = "REPLY_QUEUE";
public interface LoadingTaskListener {
void onResourceLoaded();
}
private final ProgressBar progressBar;
private final LoadingTaskListener loadingTaskListener;
private ConnectionFactory connectionFactory;
public LoadingTask(ProgressBar progressBar, LoadingTaskListener loadingTaskListener) {
this.progressBar = progressBar;
this.loadingTaskListener = loadingTaskListener;
this.connectionFactory = new ConnectionFactory();
connectionFactory.setAutomaticRecoveryEnabled(true);
}
#Override
protected Integer doInBackground(String... params) {
try {
/*init rabbitMQ Context*/
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
channel.basicQos(1);
channel.queueDeclare(DATA_QUEUE.getName(), false, false, false, null);
AMQP.Queue.DeclareOk q = channel.queueDeclare();
channel.queueBind(q.getQueue(), "amq.fanout", "chat");
QueueingConsumer consumer = new QueueingConsumer(channel);
channel.basicConsume(replyQueue, true, consumer);
/* initiate RPC */
String corrId = java.util.UUID.randomUUID().toString();
AMQP.BasicProperties props = new AMQP.BasicProperties.Builder()
.correlationId(corrId)
.replyTo(replyQueue)
.build();
AmqpRequest request = new AmqpRequest(LIST_IMAGE);
Gson gson = new Gson();
String jsonRequest = gson.toJson(request);
channel.basicPublish(MAIN_EXCHANGE.getName(), DATA_QUEUE.getRoutingKey(), props, jsonRequest.getBytes());
String response;
while (true) {
QueueingConsumer.Delivery delivery = consumer.nextDelivery();
if (delivery.getProperties().getCorrelationId().equals(corrId)) {
response = new String(delivery.getBody());
break;
}
}
System.out.println(response);
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
// Dummy Data until i can't connect to rabbitMQ
return 1234;
}
}
Is it really possible to connect Android on RabbitMQ, or should i use a kind of http bridge ?
Could anyone provide me an exemple for both http bridge or RabbitMQ connection.
Thank you

NullPointerException while subscribing to a topic on MqttAndroidClient

I have used Android Service jar from Paho Eclipse repo. I am hitting NUllPOinterException while subscribing to any topic after client connection.
public void connect(View view) {
MqttConnectOptions conOpt = new MqttConnectOptions();
String uri = "tcp://" + host + ":" + port;
boolean cleanSession = true;
// int timeout = 60 ;
// int keepalive = 60 ;
clientHandle = uri + clientId;
MqttAndroidClient client;
client = Connections.getInstance(this)
.createClient(this, uri, clientId);
Connection conn = new Connection(clientHandle, clientId, host, port,
this, client, sslConnection);
conOpt.setCleanSession(cleanSession);
// conOpt.setConnectionTimeout(timeout);
conOpt.setKeepAliveInterval(100);;
MqttCallbackHandler callback = new MqttCallbackHandler(this,
MainActivity.this, clientHandle);
conn.addConnectionOptions(conOpt);
Connections.getInstance(this).addConnection(conn);
String[] topics = { "hello", "hi" };
int qos = 0;
try {
IMqttToken t = client.connect(conOpt, null, new ActionListener(this,
Action.CONNECT, uri, (String[]) null));
//t.waitForCompletion(90);
client.setCallback(callback);
IMqttToken token = Connections
.getInstance(this)
.getConnection(clientHandle)
.getClient()
.subscribe(
"shatinTopic",
qos,
null,
new ActionListener(this, Action.SUBSCRIBE, uri,
topics));
Log.d("SUBSCRIBE", token.getResponse().toString());
} catch (MqttException e) {
e.getCause();
} catch (NullPointerException e) {
e.getCause();
} catch (Exception e) {
e.getCause();
}
}
Errors :
11-09 15:17:24.702: E/AndroidRuntime(26671): Caused by: java.lang.NullPointerException
11-09 15:17:24.702: E/AndroidRuntime(26671): at org.eclipse.paho.android.service.MqttAndroidClient.subscribe(MqttAndroidClient.java:788)
Can someone please help where exactly things are going wrong.
thanks in advance !

Got this answer from paho dev mailing list.
Because connect is asynchronous, and the connection may not established the time you call subscribe.
you should either waitForCompletion or call subscribe in IMqttActionListener.onSuccess, if you are using IMqttToken connect(MqttConnectOptions options, Object userContext, IMqttActionListener callback)
Although waitForCompletion gave server time out error, subscribing on onSuccess method of listener solved the issue.