fix rocketmq example errors.

spring-cloud-alibaba-examples/rocketmq-example/rocketmq-delay-consume-example/src/main/java/com/alibaba/cloud/examples/delay/RocketMQDelayConsumeApplication.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.alibaba.cloud.examples.broadcast;
+package com.alibaba.cloud.examples.delay;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -47,6 +47,10 @@ public class RocketMQDelayConsumeApplication {
 		SpringApplication.run(RocketMQDelayConsumeApplication.class, args);
 	}
 
+	/**
+	 * Produce delay messages
+	 * @return
+	 */
 	@Bean
 	public ApplicationRunner producerDelay() {
 		return args -> {

spring-cloud-alibaba-examples/rocketmq-example/rocketmq-orderly-consume-example/src/main/java/com/alibaba/cloud/examples/orderly/OrderlyMessageQueueSelector.java

@@ -36,10 +36,17 @@ import org.springframework.stereotype.Component;
 public class OrderlyMessageQueueSelector implements MessageQueueSelector {
 	private static final Logger log = LoggerFactory
 			.getLogger(OrderlyMessageQueueSelector.class);
+
+	/**
+	 * to select a fixed queue by id
+	 * @param mqs
+	 * @param msg
+	 * @param arg
+	 * @return
+	 */
 	@Override
 	public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
 		Integer id = (Integer) ((MessageHeaders) arg).get(MessageConst.PROPERTY_ORIGIN_MESSAGE_ID);
-		String tag = (String) ((MessageHeaders) arg).get(MessageConst.PROPERTY_TAGS);
 		int index = id % RocketMQOrderlyConsumeApplication.tags.length % mqs.size();
 		return mqs.get(index);
 	}

spring-cloud-alibaba-examples/rocketmq-example/rocketmq-sql-consume-example/src/main/java/com/alibaba/cloud/examples/sql/RocketMQSqlConsumeApplication.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.alibaba.cloud.examples.broadcast;
+package com.alibaba.cloud.examples.sql;
 
 import java.util.HashMap;
 import java.util.Map;