pass checkstyle plugin

spring-cloud-alibaba-examples/sentinel-example/sentinel-core-example/src/main/java/com/alibaba/cloud/examples/ExceptionUtil.java

@@ -25,7 +25,11 @@ import org.springframework.http.client.ClientHttpRequestExecution;
 /**
  * @author fangjian
  */
-public class ExceptionUtil {
+public final class ExceptionUtil {
+
+	private ExceptionUtil() {
+
+	}
 
 	public static SentinelClientHttpResponse handleException(HttpRequest request,
 			byte[] body, ClientHttpRequestExecution execution, BlockException ex) {

spring-cloud-alibaba-examples/sentinel-example/sentinel-feign-example/sentinel-feign-consumer-example/src/main/java/com/alibaba/cloud/examples/fallback/EchoServiceFallback.java

@@ -33,7 +33,7 @@ public class EchoServiceFallback implements EchoService {
 	}
 
 	/**
-	 * 调用服务提供方的输出接口
+	 * 调用服务提供方的输出接口.
 	 * @param str 用户输入
 	 * @return
 	 */

spring-cloud-alibaba-examples/sentinel-example/sentinel-feign-example/sentinel-feign-consumer-example/src/main/java/com/alibaba/cloud/examples/service/EchoService.java

@@ -33,9 +33,9 @@ import org.springframework.web.bind.annotation.PathVariable;
 public interface EchoService {
 
 	/**
-	 * 调用服务提供方的输出接口
+	 * 调用服务提供方的输出接口.
 	 * @param str 用户输入
-	 * @return
+	 * @return echo result
 	 */
 	@GetMapping("/echo/{str}")
 	String echo(@PathVariable("str") String str);