diff --git a/core/api/src/main/java/org/onosproject/net/DefaultPath.java b/core/api/src/main/java/org/onosproject/net/DefaultPath.java
index a4789ca..2da2463 100644
--- a/core/api/src/main/java/org/onosproject/net/DefaultPath.java
+++ b/core/api/src/main/java/org/onosproject/net/DefaultPath.java
@@ -88,7 +88,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(links);
+        return links.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/DeviceId.java b/core/api/src/main/java/org/onosproject/net/DeviceId.java
index 5331342..e2c1214 100644
--- a/core/api/src/main/java/org/onosproject/net/DeviceId.java
+++ b/core/api/src/main/java/org/onosproject/net/DeviceId.java
@@ -75,7 +75,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(str);
+        return str.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/behaviour/BridgeName.java b/core/api/src/main/java/org/onosproject/net/behaviour/BridgeName.java
index 3f78295..a15217c 100644
--- a/core/api/src/main/java/org/onosproject/net/behaviour/BridgeName.java
+++ b/core/api/src/main/java/org/onosproject/net/behaviour/BridgeName.java
@@ -52,7 +52,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(name);
+        return name.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
index bcc8bd8..4e5d39a 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
@@ -516,7 +516,7 @@
 
         @Override
         public int hashCode() {
-            return Objects.hash(type().ordinal());
+            return type().ordinal();
         }
 
         @Override
@@ -550,7 +550,7 @@
 
         @Override
         public int hashCode() {
-            return Objects.hash(type().ordinal());
+            return type().ordinal();
         }
 
         @Override
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/L0ModificationInstruction.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/L0ModificationInstruction.java
index a6e5903..4af3d16 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/L0ModificationInstruction.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/L0ModificationInstruction.java
@@ -114,7 +114,7 @@
 
         @Override
         public int hashCode() {
-            return Objects.hash(lambda);
+            return lambda.hashCode();
         }
 
         @Override
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/L1ModificationInstruction.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/L1ModificationInstruction.java
index c6847d1..b72dd7b 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/L1ModificationInstruction.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/L1ModificationInstruction.java
@@ -62,7 +62,7 @@
 
         @Override
         public int hashCode() {
-            return Objects.hash(oduSignalId);
+            return oduSignalId.hashCode();
         }
 
         @Override
diff --git a/core/api/src/main/java/org/onosproject/net/group/DefaultGroup.java b/core/api/src/main/java/org/onosproject/net/group/DefaultGroup.java
index 546a451..97f8aed 100644
--- a/core/api/src/main/java/org/onosproject/net/group/DefaultGroup.java
+++ b/core/api/src/main/java/org/onosproject/net/group/DefaultGroup.java
@@ -186,7 +186,7 @@
      */
     @Override
     public int hashCode() {
-        return super.hashCode() + Objects.hash(id);
+        return Objects.hash(super.hashCode(), id);
     }
 
     /*
diff --git a/core/api/src/main/java/org/onosproject/net/intent/constraint/BandwidthConstraint.java b/core/api/src/main/java/org/onosproject/net/intent/constraint/BandwidthConstraint.java
index 20ccb55..444feee 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/constraint/BandwidthConstraint.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/constraint/BandwidthConstraint.java
@@ -87,7 +87,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(bandwidth);
+        return bandwidth.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/intent/constraint/LambdaConstraint.java b/core/api/src/main/java/org/onosproject/net/intent/constraint/LambdaConstraint.java
index 9dd813b..7811a00 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/constraint/LambdaConstraint.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/constraint/LambdaConstraint.java
@@ -69,7 +69,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(lambda);
+        return Objects.hashCode(lambda);
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/intent/constraint/LatencyConstraint.java b/core/api/src/main/java/org/onosproject/net/intent/constraint/LatencyConstraint.java
index 54eb4ea..aecef87 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/constraint/LatencyConstraint.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/constraint/LatencyConstraint.java
@@ -67,7 +67,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(latency);
+        return latency.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/intent/constraint/ObstacleConstraint.java b/core/api/src/main/java/org/onosproject/net/intent/constraint/ObstacleConstraint.java
index cb1e6b2..ca4f3fd 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/constraint/ObstacleConstraint.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/constraint/ObstacleConstraint.java
@@ -66,7 +66,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(obstacles);
+        return obstacles.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/intent/constraint/WaypointConstraint.java b/core/api/src/main/java/org/onosproject/net/intent/constraint/WaypointConstraint.java
index 1acf6df..4839fee 100644
--- a/core/api/src/main/java/org/onosproject/net/intent/constraint/WaypointConstraint.java
+++ b/core/api/src/main/java/org/onosproject/net/intent/constraint/WaypointConstraint.java
@@ -91,7 +91,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(waypoints);
+        return waypoints.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceAllocation.java b/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceAllocation.java
index 74f6e10..05cf28f 100644
--- a/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceAllocation.java
+++ b/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceAllocation.java
@@ -53,7 +53,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(bandwidth);
+        return bandwidth.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceRequest.java b/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceRequest.java
index e07309c..722b870 100644
--- a/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceRequest.java
+++ b/core/api/src/main/java/org/onosproject/net/resource/link/BandwidthResourceRequest.java
@@ -53,7 +53,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(bandwidth);
+        return bandwidth.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/resource/link/LambdaResourceAllocation.java b/core/api/src/main/java/org/onosproject/net/resource/link/LambdaResourceAllocation.java
index 545f025..161cf45 100644
--- a/core/api/src/main/java/org/onosproject/net/resource/link/LambdaResourceAllocation.java
+++ b/core/api/src/main/java/org/onosproject/net/resource/link/LambdaResourceAllocation.java
@@ -53,7 +53,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(lambda);
+        return Objects.hashCode(lambda);
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/resource/link/MplsLabelResourceAllocation.java b/core/api/src/main/java/org/onosproject/net/resource/link/MplsLabelResourceAllocation.java
index 1091153..cc9edc2 100644
--- a/core/api/src/main/java/org/onosproject/net/resource/link/MplsLabelResourceAllocation.java
+++ b/core/api/src/main/java/org/onosproject/net/resource/link/MplsLabelResourceAllocation.java
@@ -54,7 +54,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(mplsLabel);
+        return Objects.hashCode(mplsLabel);
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/topology/ClusterId.java b/core/api/src/main/java/org/onosproject/net/topology/ClusterId.java
index 676f006..1e6780f 100644
--- a/core/api/src/main/java/org/onosproject/net/topology/ClusterId.java
+++ b/core/api/src/main/java/org/onosproject/net/topology/ClusterId.java
@@ -53,7 +53,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(id);
+        return id;
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyEdge.java b/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyEdge.java
index dacb5fd..99d700e 100644
--- a/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyEdge.java
+++ b/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyEdge.java
@@ -20,6 +20,7 @@
 import java.util.Objects;
 
 import static com.google.common.base.MoreObjects.toStringHelper;
+import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
  * Implementation of the topology edge backed by a link.
@@ -40,7 +41,7 @@
     public DefaultTopologyEdge(TopologyVertex src, TopologyVertex dst, Link link) {
         this.src = src;
         this.dst = dst;
-        this.link = link;
+        this.link = checkNotNull(link);
     }
 
     @Override
@@ -60,7 +61,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(link);
+        return link.hashCode();
     }
 
     @Override
diff --git a/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyVertex.java b/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyVertex.java
index 07a09cb..4782bc9 100644
--- a/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyVertex.java
+++ b/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyVertex.java
@@ -42,7 +42,7 @@
 
     @Override
     public int hashCode() {
-        return Objects.hash(deviceId);
+        return deviceId.hashCode();
     }
 
     @Override