[jacorb-developer] Investigating COMM_FAILURE with abnormal closed connection at JacORB 3.5

[Vinicius (Tec)]

Hi everybody,

Sorry for bring this issue back but i'm still trying to figure out a better
solution for the bug reported at
http://www.jacorb.org/bugzilla/show_bug.cgi?id=1014 than using _duplicate
when sharing a Object between multiple threads. The stack error:

Exception id: IDL:omg.org/CORBA/NO_PERMISSION:1.0
Operation name: hello2
org.omg.CORBA.COMM_FAILURE: IOException: java.net.SocketException: Socket
closed  vmcid: 0x0  minor code: 0  completed: No
    at
org.jacorb.orb.etf.ConnectionBase.to_COMM_FAILURE(ConnectionBase.java:152)
    at
org.jacorb.orb.iiop.IIOPConnection.handleCommFailure(IIOPConnection.java:79)
    at
org.jacorb.orb.etf.StreamConnectionBase.flush(StreamConnectionBase.java:227)
    at
org.jacorb.orb.giop.GIOPConnection.sendMessage(GIOPConnection.java:1094)
    at
org.jacorb.orb.giop.GIOPConnection.sendRequest(GIOPConnection.java:1020)
    at
org.jacorb.orb.giop.ClientConnection.sendRequest(ClientConnection.java:309)
    at
org.jacorb.orb.giop.ClientConnection.sendRequest(ClientConnection.java:290)
    at org.jacorb.orb.Delegate._invoke_internal(Delegate.java:1371)
    at org.jacorb.orb.Delegate.invoke_internal(Delegate.java:1209)
    at org.jacorb.orb.Delegate.invoke(Delegate.java:1197)
    at org.omg.CORBA.portable.ObjectImpl._invoke(ObjectImpl.java:475)
    at demo._HelloStub.hello(_HelloStub.java:35)
    at demo.Client.main(Client.java:58)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)


First, let me explain why using _duplicate, while it is surely a good
workaround for general use, is not a good solution for our project. We have
a Java SDK based on JacORB that must be used by the applications that need
to connect to our server. In order to apply the _duplicate solution
throughout the SDK code we'd have to know whether a Object will be shared
between multiple threads or not but such knowledge is restrict to the
application developer.

So, I'm beginning to analyse how JacORB manages its connection to discover
a better solution and, hopefully, implement it.

So far, a colleague of mine found what it seems to be a quick workaround
for this issue:

diff --git a/core/src/main/java/org/jacorb/orb/giop/ClientConnection.java
b/core/src/main/java/org/jacorb/orb/giop/ClientConnection.java
index ab72273..90e7be7 100644
--- a/core/src/main/java/org/jacorb/orb/giop/ClientConnection.java
+++ b/core/src/main/java/org/jacorb/orb/giop/ClientConnection.java
@@ -326,7 +326,8 @@ public class ClientConnection

    public void close()
    {
-        connection.close();
+        if (!connection.hasPendingMessages())
+            connection.close();
    }

We test at bug 1014 and it seems to fix the problem. However, we did not
evaluate yet the side effects of this modification.

We're trying to evaluate the side effects of this modification. It isn't an
easy task, though. Delegate depends on ClientConnection and Delegate seems
designed to be used only by a single thread at time.
We really appreciate any insights about how to evolve Delegate class to a
multithread fashion behaviour.

Best regards,

Vinicius