= code cleanup

- for loop replaceable with enhanced 'for' loop
  - using diamond in generic type
  - collapse try catch exception
  - using try-with-resource
  - using  List#sort instead of Collections#sort
  - replaced lambda with method reference
  - using native compare method to compare numbers
  - using switch instead of if for in ESSyncUtil

admin/admin-web/src/main/java/com/alibaba/otter/canal/admin/connector/SimpleAdminConnector.java

@@ -108,9 +108,7 @@ public class SimpleAdminConnector implements AdminConnector {
             }
 
             connected = true;
-        } catch (IOException e) {
-            throw new ServiceException(e);
-        } catch (NoSuchAlgorithmException e) {
+        } catch (IOException | NoSuchAlgorithmException e) {
             throw new ServiceException(e);
         }
     }