Re-organize all client/server sample code to separate client and server classes into client and server packages, respectively.

Rename sample.ServerConfig class to sample.server.GemFireServer and apply the GemFireServer Gradle Plugin.

Change all 'spring.session.data.gemfire.*' and 'spring.session.data.geode.*' properties to use the SDG property prefixed with 'spring.data.gemfire.*'.

samples/javaconfig/gemfire-clientserver/src/main/java/sample/client/Initializer.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2017 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 sample.client;
+
+import org.springframework.session.web.context.AbstractHttpSessionApplicationInitializer;
+
+// tag::class[]
+public class Initializer extends AbstractHttpSessionApplicationInitializer { // <1>
+
+	public Initializer() {
+		super(ClientConfig.class); // <2>
+	}
+}
+// end::class[]