Fix checkstyle errors

(cherry picked from commit bd98343b9c)

servlet/spring-boot/java/oauth2/webclient/src/main/java/example/OAuth2WebClientApplication.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package example;
 
 import org.springframework.boot.SpringApplication;

servlet/spring-boot/java/oauth2/webclient/src/main/java/example/OAuth2WebClientController.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package example;
 
 import org.springframework.stereotype.Controller;

servlet/spring-boot/java/oauth2/webclient/src/main/java/example/RegisteredOAuth2AuthorizedClientController.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package example;
 
 import org.springframework.security.oauth2.client.OAuth2AuthorizedClient;

servlet/spring-boot/java/oauth2/webclient/src/main/java/example/SecurityConfiguration.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package example;
 
 import org.springframework.context.annotation.Bean;