Use diamond operator

Change-Id: Ief0dabe762acb740476eba5eb033dcfce76426b2
diff --git a/src/main/java/org/onosproject/segmentrouting/config/NetworkConfig.java b/src/main/java/org/onosproject/segmentrouting/config/NetworkConfig.java
index 7f0803f..0c7749e 100644
--- a/src/main/java/org/onosproject/segmentrouting/config/NetworkConfig.java
+++ b/src/main/java/org/onosproject/segmentrouting/config/NetworkConfig.java
@@ -45,8 +45,8 @@
      * Default constructor.
      */
     public NetworkConfig() {
-        switches = new ArrayList<SwitchConfig>();
-        links = new ArrayList<LinkConfig>();
+        switches = new ArrayList<>();
+        links = new ArrayList<>();
     }
 
     @JsonProperty("comment")