= 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

common/src/main/java/com/alibaba/otter/canal/common/utils/AddressUtils.java

@@ -18,20 +18,11 @@ public class AddressUtils {
     private static final Pattern IP_PATTERN   = Pattern.compile("[0-9]{1,3}(\\.[0-9]{1,3}){3,}");
 
     public static boolean isAvailablePort(int port) {
-        ServerSocket ss = null;
-        try {
-            ss = new ServerSocket(port);
+        try (ServerSocket ss = new ServerSocket(port)) {
             ss.bind(null);
             return true;
         } catch (IOException e) {
             return false;
-        } finally {
-            if (ss != null) {
-                try {
-                    ss.close();
-                } catch (IOException e) {
-                }
-            }
         }
     }
 

common/src/main/java/com/alibaba/otter/canal/common/utils/JsonUtils.java

@@ -71,14 +71,11 @@ public class JsonUtils {
      */
     public static String marshalToString(Object obj, String... fliterFields) {
         final List<String> propertyFliters = Arrays.asList(fliterFields);
-        SerializeWriter out = new SerializeWriter();
-        try {
+        try (SerializeWriter out = new SerializeWriter()) {
             JSONSerializer serializer = new JSONSerializer(out);
             serializer.getPropertyFilters().add((source, name, value) -> !propertyFliters.contains(name));
             serializer.write(obj);
             return out.toString();
-        } finally {
-            out.close();
         }
     }