Add logging of stack trace of unexpected Throwable.

src/altk/comm/engine/Broadcast.java

@@ -1,5 +1,7 @@
 package altk.comm.engine;
 
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -16,6 +18,7 @@ import javax.servlet.http.HttpServletRequest;
 
 import org.apache.log4j.Logger;
 import org.apache.log4j.NDC;
+import org.omg.CORBA_2_3.portable.OutputStream;
 
 import altk.comm.engine.exception.BroadcastException;
 import altk.comm.engine.exception.EngineException;
@@ -309,6 +312,8 @@ public abstract class Broadcast
                     }
                     catch (Throwable t)
                     {
+                        // This is unexpected. Log stack trace
+                        myLogger.error("Caught unexpected Throwable", t);
                         terminate(BroadcastState.ABORTED, t + ": " + t.getMessage());
                     }
                 }