Fix NPE in WebSocketMessageBrokerSecurityBeanDefinitionParser

Fixes gh-4112
Closes gh-4194

config/src/test/java/org/springframework/security/config/websocket/MessageSecurityPostProcessorTest.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.security.config.websocket;
+
+import org.junit.Test;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.GenericBeanDefinition;
+import org.springframework.beans.factory.support.SimpleBeanDefinitionRegistry;
+
+public class MessageSecurityPostProcessorTest {
+
+	private WebSocketMessageBrokerSecurityBeanDefinitionParser.MessageSecurityPostProcessor postProcessor =
+		new WebSocketMessageBrokerSecurityBeanDefinitionParser.MessageSecurityPostProcessor("id", false);
+
+	@Test
+	public void handlesBeansWithoutClass() {
+		BeanDefinitionRegistry registry = new SimpleBeanDefinitionRegistry();
+		registry.registerBeanDefinition("beanWithoutClass", new GenericBeanDefinition());
+		postProcessor.postProcessBeanDefinitionRegistry(registry);
+	}
+}