Added showcase for JDK 8's Optional support on repository methods.

Abbreviated JPA sample module folder names. Renamed the Java 8 auditing sample module to Java 8 module as it not only contains samples for auditing anymore.

jpa/interceptors/src/test/java/example/springdata/jpa/interceptors/InterceptorIntegrationTest.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * 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 example.springdata.jpa.interceptors;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = ApplicationConfiguration.class)
+public class InterceptorIntegrationTest {
+
+	@Autowired CustomerRepository repository;
+
+	@Test
+	public void foo() {
+
+		Customer customer = new Customer();
+		customer.firstname = "Dave";
+		customer.lastname = "Matthews";
+
+		repository.save(customer);
+	}
+}

jpa/interceptors/src/test/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+
+	<appender name="console" class="ch.qos.logback.core.ConsoleAppender">
+		<encoder>
+			<pattern>%d %5p %40.40c:%4L - %m%n</pattern>
+		</encoder>
+	</appender>
+
+	<logger name="org.springframework" level="error" />
+	<logger name="org.springframework.aop.interceptor" level="trace" />
+
+	<root level="error">
+		<appender-ref ref="console" />
+	</root>
+
+</configuration>