diff --git a/java/android/net/sip/SipManager.java b/java/android/net/sip/SipManager.java
index dce46fe..cd0b5c4 100644
--- a/java/android/net/sip/SipManager.java
+++ b/java/android/net/sip/SipManager.java
@@ -471,6 +471,10 @@
         try {
             ISipSession session = mSipService.createSession(localProfile,
                     createRelay(listener, localProfile.getUriString()));
+            if (session == null) {
+                throw new SipException(
+                        "SipService.createSession() returns null");
+            }
             session.register(expiryTime);
         } catch (RemoteException e) {
             throw new SipException("register()", e);
@@ -492,6 +496,10 @@
         try {
             ISipSession session = mSipService.createSession(localProfile,
                     createRelay(listener, localProfile.getUriString()));
+            if (session == null) {
+                throw new SipException(
+                        "SipService.createSession() returns null");
+            }
             session.unregister();
         } catch (RemoteException e) {
             throw new SipException("unregister()", e);
@@ -513,7 +521,7 @@
         try {
             String callId = getCallId(incomingCallIntent);
             ISipSession s = mSipService.getPendingSession(callId);
-            return new SipSession(s);
+            return ((s == null) ? null : new SipSession(s));
         } catch (RemoteException e) {
             throw new SipException("getSessionFor()", e);
         }