More corrections for SocketInitiator/Acceptor tests (#425)

* More corrections for SocketInitiator/Acceptor tests
 - ensure connector is stopped when first assertion in `finally` block fails
* Prevent NPE when `stop()` method is called prior to `start()`

Author: chrjohn

quickfixj-core/src/main/java/quickfix/mina/SingleThreadedEventHandlingStrategy.java

@@ -194,7 +194,9 @@ public void stopHandlingMessages(boolean join) {
         stopHandlingMessages();
         if (join) {
             try {
-                messageProcessingThread.join();
+                if (messageProcessingThread != null) {
+                    messageProcessingThread.join();
+                }
             } catch (InterruptedException e) {
                 sessionConnector.log.warn("{} interrupted.", MESSAGE_PROCESSOR_THREAD_NAME);
                 Thread.currentThread().interrupt();

quickfixj-core/src/test/java/quickfix/SocketAcceptorTest.java

@@ -102,22 +102,25 @@ public void testRestartOfAcceptor() throws Exception {
             assertTrue("acceptor should have logged on by now", acceptor.isLoggedOn());
             assertTrue("initiator should have logged on by now", initiator.isLoggedOn());
         } finally {
-            if (initiator != null) {
-                try {
-                    initiator.stop();
-                } catch (RuntimeException e) {
-                    log.error(e.getMessage(), e);
+            try {
+                if (initiator != null) {
+                    try {
+                        initiator.stop();
+                    } catch (RuntimeException e) {
+                        log.error(e.getMessage(), e);
+                    }
                 }
-            }
-            testAcceptorApplication.waitForLogout();
-            if (acceptor != null) {
-                try {
-                    acceptor.stop();
-                } catch (RuntimeException e) {
-                    log.error(e.getMessage(), e);
+                testAcceptorApplication.waitForLogout();
+            } finally {
+                if (acceptor != null) {
+                    try {
+                        acceptor.stop();
+                    } catch (RuntimeException e) {
+                        log.error(e.getMessage(), e);
+                    }
                 }
+                testInitiatorApplication.waitForLogout();
             }
-            testInitiatorApplication.waitForLogout();
         }
     }