[ONOS-7667] Code clean-up in compliance with Java8

Change-Id: Ieb17110357d8fa13705ebe9c86559b0863e77751
diff --git a/protocols/ovsdb/api/src/test/java/org/onosproject/ovsdb/controller/driver/OvsdbControllerAdapter.java b/protocols/ovsdb/api/src/test/java/org/onosproject/ovsdb/controller/driver/OvsdbControllerAdapter.java
index 2f2b1fd..842f753 100644
--- a/protocols/ovsdb/api/src/test/java/org/onosproject/ovsdb/controller/driver/OvsdbControllerAdapter.java
+++ b/protocols/ovsdb/api/src/test/java/org/onosproject/ovsdb/controller/driver/OvsdbControllerAdapter.java
@@ -25,7 +25,7 @@
 import org.onosproject.ovsdb.controller.OvsdbNodeListener;
 
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Consumer;
@@ -35,7 +35,7 @@
  */
 public class OvsdbControllerAdapter implements OvsdbController {
     protected ConcurrentHashMap<OvsdbNodeId, OvsdbClientServiceAdapter> ovsdbClients =
-            new ConcurrentHashMap<OvsdbNodeId, OvsdbClientServiceAdapter>();
+            new ConcurrentHashMap<>();
 
     @Override
     public void addNodeListener(OvsdbNodeListener listener) {
@@ -60,7 +60,7 @@
     @Override
     public List<OvsdbNodeId> getNodeIds() {
         long port = 6653;
-        return new ArrayList<OvsdbNodeId>(Arrays.asList(
+        return new ArrayList<>(Collections.singletonList(
                 new OvsdbNodeId(IpAddress.valueOf("127.0.0.1"), port)));
     }