Safer context class loader message factory init

quickfixj-core/src/main/java/quickfix/DefaultMessageFactory.java

@@ -118,8 +118,12 @@ public void addFactory(String beginString, String factoryClassName) throws Class
             // try using our own classloader
             factoryClass = (Class<? extends MessageFactory>) Class.forName(factoryClassName);
         } catch (ClassNotFoundException e) {
-                // try using context classloader (i.e. allow caller to specify it)
-            Thread.currentThread().getContextClassLoader().loadClass(factoryClassName);
+            // try using context classloader (i.e. allow caller to specify it)
+            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+
+            if (contextClassLoader != null) {
+                factoryClass = (Class<? extends MessageFactory>) contextClassLoader.loadClass(factoryClassName);
+            }
         }
         // if factory is found, add it
         if (factoryClass != null) {

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

@@ -1,6 +1,10 @@
 package quickfix;
 
 import static org.junit.Assert.*;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static quickfix.FixVersions.*;
 import static quickfix.field.ApplVerID.*;
 
@@ -9,6 +13,7 @@
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 import quickfix.field.*;
+import quickfix.fix44.MessageFactory;
 import quickfix.test.util.ExpectedTestFailure;
 
 /**
@@ -81,6 +86,24 @@ protected void execute() throws Throwable {
                 factory.create(BEGINSTRING_FIX40, MsgType.MARKET_DATA_SNAPSHOT_FULL_REFRESH, NoMDEntries.FIELD));
     }
 
+    @Test
+    public void testContextClassLoaderFactory() throws ClassNotFoundException {
+        ClassLoader customLoader = mock(ClassLoader.class);
+        doReturn(MessageFactory.class).when(customLoader).loadClass("foo.DefaultMessageFactory");
+
+        ClassLoader previousClassLoader = Thread.currentThread().getContextClassLoader();
+        Thread.currentThread().setContextClassLoader(customLoader);
+
+        try {
+            factory.addFactory(BEGINSTRING_FIX44, "foo.DefaultMessageFactory");
+        } finally {
+            Thread.currentThread().setContextClassLoader(previousClassLoader);
+        }
+
+        verify(customLoader).loadClass("foo.DefaultMessageFactory");
+        verifyNoMoreInteractions(customLoader);
+    }
+
     private static void assertMessage(Class<?> expectedMessageClass, String expectedMessageType, Message message) throws Exception {
         assertEquals(expectedMessageClass, message.getClass());
         assertEquals(expectedMessageType, message.getHeader().getString(MsgType.FIELD));