Use dianmond operator

Change-Id: I551dd9443b10ef17832f74a554486b7605e9866a
diff --git a/apps/optical/src/main/java/org/onosproject/optical/cfg/OpticalNetworkConfig.java b/apps/optical/src/main/java/org/onosproject/optical/cfg/OpticalNetworkConfig.java
index f3f8d17..2ef5cd5 100644
--- a/apps/optical/src/main/java/org/onosproject/optical/cfg/OpticalNetworkConfig.java
+++ b/apps/optical/src/main/java/org/onosproject/optical/cfg/OpticalNetworkConfig.java
@@ -34,8 +34,8 @@
     private List<OpticalLinkDescription> opticalLinks;
 
     public OpticalNetworkConfig() {
-        opticalSwitches = new ArrayList<OpticalSwitchDescription>();
-        opticalLinks = new ArrayList<OpticalLinkDescription>();
+        opticalSwitches = new ArrayList<>();
+        opticalLinks = new ArrayList<>();
     }
 
     public List<OpticalSwitchDescription> getOpticalSwitches() {