Attempts to fix a NullPointerException in CallSessionImpl#stopSendStreaming(RTPManager)/SendStream#close()/com.sun.media.rtp.RTCPTransmitter.bye() upon call hang-up after reinvites have been received in the call. The offered solution is to close existing SendStream instances just before creating the new ones because the new ones correspond to the latest SDP offer.

src/net/java/sip/communicator/impl/media/CallSessionImpl.java

@@ -6,11 +6,14 @@
  */
 package net.java.sip.communicator.impl.media;
 
-import java.awt.Component;
+import gnu.java.zrtp.*;
+
+import java.awt.*;
 import java.io.*;
 import java.net.*;
 import java.text.*;
 import java.util.*;
+import java.util.List;
 
 import javax.media.*;
 import javax.media.control.*;
@@ -32,8 +35,6 @@
 import net.java.sip.communicator.service.protocol.event.*;
 import net.java.sip.communicator.util.*;
 
-import gnu.java.zrtp.*;
-
 /**
  * Contains parameters associated with a particular Call such as media (audio
  * video), a reference to the call itself, RTPManagers and others.
@@ -565,11 +566,30 @@ private boolean stopSendStreaming(RTPManager rtpManager)
             {
                 stream.getDataSource().stop();
                 stream.stop();
-                stream.close();
+
+                try
+                {
+                    stream.close();
+                }
+                catch (NullPointerException npe)
+                {
+                    /*
+                     * Sometimes com.sun.media.rtp.RTCPTransmitter#bye() may
+                     * throw NullPointerException but it does not seem to be
+                     * guaranteed because it does not happen while debugging and
+                     * stopping at a breakpoint on SendStream#close(). One of
+                     * the cases in which it appears upon call hang-up is if we
+                     * do not close the "old" SendStreams upon reinvite(s).
+                     * Though we are now closing such SendStreams, ignore the
+                     * exception here just in case because we already ignore
+                     * IOExceptions.
+                     */
+                    logger.error("Failed to close stream " + stream, npe);
+                }
             }
-            catch (IOException ex)
+            catch (IOException ioe)
             {
-                logger.warn("Failed to stop stream.", ex);
+                logger.warn("Failed to stop stream.", ioe);
             }
             stoppedAtLeastOneStream = true;
         }
@@ -1265,6 +1285,13 @@ private String processSdpStr(CallPeer peer,
                                     , MediaException.INTERNAL_ERROR
                                     , exc);
         }
+
+        /*
+         * Close the existing streams because we're about to create new ones.
+         * Otherwise, a NullPointerException may be thrown in SendStream#close()
+         * upon call hang-up for some of the streams. 
+         */
+        stopSendStreaming();
         //create and init the streams (don't start streaming just yet but wait
         //for the call to enter the connected state).
         createSendStreams(mediaDescriptions);