Harmonize resource collectors.

Change-Id: I51fdf9cdf57d3146bd9401ff67e13063830519e4
diff --git a/core/net/src/main/java/org/onosproject/net/newresource/impl/ResourceDeviceListener.java b/core/net/src/main/java/org/onosproject/net/newresource/impl/ResourceDeviceListener.java
index ae60d50..9df5f50 100644
--- a/core/net/src/main/java/org/onosproject/net/newresource/impl/ResourceDeviceListener.java
+++ b/core/net/src/main/java/org/onosproject/net/newresource/impl/ResourceDeviceListener.java
@@ -45,9 +45,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.SortedSet;
-import java.util.TreeSet;
 import java.util.concurrent.ExecutorService;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
@@ -206,10 +204,9 @@
             }
             LambdaQuery query = handler.behaviour(LambdaQuery.class);
             if (query != null) {
-                Supplier<SortedSet<OchSignal>> supplier = () -> new TreeSet<>(new DefaultOchSignalComparator());
                 return query.queryLambdas(port).stream()
                         .flatMap(x -> OchSignal.toFlexGrid(x).stream())
-                        .collect(Collectors.toCollection(supplier));
+                        .collect(Collectors.toCollection(DefaultOchSignalComparator::newOchSignalTreeSet));
             } else {
                 return Collections.emptySortedSet();
             }