diff --git a/apps/mfwd/src/main/java/org/onosproject/mfwd/impl/McastForwarding.java b/apps/mfwd/src/main/java/org/onosproject/mfwd/impl/McastForwarding.java
index c7326b8..16d7da3 100644
--- a/apps/mfwd/src/main/java/org/onosproject/mfwd/impl/McastForwarding.java
+++ b/apps/mfwd/src/main/java/org/onosproject/mfwd/impl/McastForwarding.java
@@ -235,7 +235,7 @@
 
             ArrayList<ConnectPoint> egressList = (ArrayList<ConnectPoint>) mcastRouteManager.fetchSinks(mRoute);
             //If there are no egress ports set return, otherwise forward the packets to their expected port.
-            if (egressList.size() == 0) {
+            if (egressList.isEmpty()) {
                 return;
             }
 
diff --git a/apps/pce/pceweb/src/main/java/org/onosproject/pceweb/PceWebTopovMessageHandler.java b/apps/pce/pceweb/src/main/java/org/onosproject/pceweb/PceWebTopovMessageHandler.java
index 8e93b80..c1a1bec 100644
--- a/apps/pce/pceweb/src/main/java/org/onosproject/pceweb/PceWebTopovMessageHandler.java
+++ b/apps/pce/pceweb/src/main/java/org/onosproject/pceweb/PceWebTopovMessageHandler.java
@@ -710,7 +710,7 @@
         Highlights highlights = new Highlights();
         paths.removeAll(paths);
         tunnelSet = tunnelService.queryTunnel(MPLS);
-        if (tunnelSet.size() == 0) {
+        if (tunnelSet.isEmpty()) {
             log.warn("Tunnel does not exist");
             sendMessage(highlightsMessage(highlights));
             return;
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/RoutingRulePopulator.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/RoutingRulePopulator.java
index 9e215a9..b691f80 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/RoutingRulePopulator.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/RoutingRulePopulator.java
@@ -559,7 +559,7 @@
         }
 
         List<Port> devPorts = srManager.deviceService.getPorts(deviceId);
-        if (devPorts == null || devPorts.size() == 0) {
+        if (devPorts == null || devPorts.isEmpty()) {
             log.warn("Device {} ports not available. Unable to add MacVlan filters",
                      deviceId);
             return null;
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java
index 7eb6894..2bd9932 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/config/DeviceConfiguration.java
@@ -357,7 +357,7 @@
                         .map(IpPrefix::getIp4Prefix)
                         .collect(Collectors.toSet());
 
-        if (subnets.size() == 0) {
+        if (subnets.isEmpty()) {
             log.info(NO_SUBNET, connectPoint);
             return null;
         } else if (subnets.size() > 1) {
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java
index 52606cf..b76a04c 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/DefaultGroupHandler.java
@@ -655,7 +655,7 @@
                     log.warn("Neighbor {} is not in the port map yet for dev:{}",
                              neighborId, deviceId);
                     return;
-                } else if (devicePortMap.get(neighborId).size() == 0) {
+                } else if (devicePortMap.get(neighborId).isEmpty()) {
                     log.warn("There are no ports for "
                             + "the Device {} in the port map yet", neighborId);
                     return;
diff --git a/apps/test/intent-perf/src/main/java/org/onosproject/intentperf/IntentPerfInstaller.java b/apps/test/intent-perf/src/main/java/org/onosproject/intentperf/IntentPerfInstaller.java
index 9b758d4..b4d7acf 100644
--- a/apps/test/intent-perf/src/main/java/org/onosproject/intentperf/IntentPerfInstaller.java
+++ b/apps/test/intent-perf/src/main/java/org/onosproject/intentperf/IntentPerfInstaller.java
@@ -358,7 +358,7 @@
                 .forEach(device -> devices.put(mastershipService.getMasterFor(device.id()), device));
 
         // ensure that we have at least one device per neighbor
-        neighbors.forEach(node -> checkState(devices.get(node).size() > 0,
+        neighbors.forEach(node -> checkState(!devices.get(node).isEmpty(),
                                              "There are no devices for {}", node));
 
         // TODO pull this outside so that createIntent can use it
diff --git a/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/table/impl/L2ForwardServiceImpl.java b/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/table/impl/L2ForwardServiceImpl.java
index 7c9c30d..582aad3 100644
--- a/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/table/impl/L2ForwardServiceImpl.java
+++ b/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/table/impl/L2ForwardServiceImpl.java
@@ -142,7 +142,7 @@
                     .withSelector(selector).fromApp(appId).makePermanent()
                     .withFlag(Flag.SPECIFIC).withPriority(MAC_PRIORITY);
             if (type.equals(Objective.Operation.ADD)) {
-                if (Sets.newHashSet(localVmPorts).size() == 0) {
+                if (Sets.newHashSet(localVmPorts).isEmpty()) {
                     flowObjectiveService.forward(deviceId, objective.remove());
                 } else {
                     flowObjectiveService.forward(deviceId, objective.add());
diff --git a/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/VtnData.java b/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/VtnData.java
index 2ee889a..c66cba6 100644
--- a/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/VtnData.java
+++ b/apps/vtn/vtnmgr/src/main/java/org/onosproject/vtn/util/VtnData.java
@@ -137,7 +137,7 @@
                     }
                 }
             });
-            if (vPorts.size() == 0) {
+            if (vPorts.isEmpty()) {
                 return null;
             }
             return vPorts.get(0);
@@ -168,7 +168,7 @@
                             }
                         }
                     });
-            if (vPorts.size() == 0) {
+            if (vPorts.isEmpty()) {
                 return null;
             }
             return vPorts.get(0);
diff --git a/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/virtualport/impl/VirtualPortManager.java b/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/virtualport/impl/VirtualPortManager.java
index ede595f..0b7d0a6 100644
--- a/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/virtualport/impl/VirtualPortManager.java
+++ b/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/virtualport/impl/VirtualPortManager.java
@@ -181,7 +181,7 @@
                 }
             }
         });
-        if (vPorts.size() == 0) {
+        if (vPorts.isEmpty()) {
             return null;
         }
         return vPorts.get(0);
@@ -196,7 +196,7 @@
                 vPorts.add(p);
             }
         });
-        if (vPorts.size() == 0) {
+        if (vPorts.isEmpty()) {
             return null;
         }
         return vPorts.get(0);
@@ -217,7 +217,7 @@
                         }
                     }
                 });
-        if (vPorts.size() == 0) {
+        if (vPorts.isEmpty()) {
             return null;
         }
         return vPorts.get(0);
diff --git a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java
index c2c4632..8691b42 100644
--- a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java
+++ b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/FloatingIpWebResource.java
@@ -99,7 +99,7 @@
                 .getFloatingIp(FloatingIpId.of(id)), GET_FAIL);
 
         ObjectNode result = new ObjectMapper().createObjectNode();
-        if (fields.size() > 0) {
+        if (!fields.isEmpty()) {
             result.set("floatingip",
                        new FloatingIpCodec().extracFields(sub, this, fields));
         } else {
diff --git a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java
index 855209c..332bd41 100644
--- a/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java
+++ b/apps/vtn/vtnweb/src/main/java/org/onosproject/vtnweb/resources/RouterWebResource.java
@@ -106,7 +106,7 @@
                 .getRouter(RouterId.valueOf(id)), NOT_EXIST);
 
         ObjectNode result = new ObjectMapper().createObjectNode();
-        if (fields.size() > 0) {
+        if (!fields.isEmpty()) {
             result.set("router",
                        new RouterCodec().extracFields(sub, this, fields));
         } else {
diff --git a/cli/src/main/java/org/onosproject/cli/net/GlobalLabelApplyCommand.java b/cli/src/main/java/org/onosproject/cli/net/GlobalLabelApplyCommand.java
index aabe72a..d3c68a6 100644
--- a/cli/src/main/java/org/onosproject/cli/net/GlobalLabelApplyCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/net/GlobalLabelApplyCommand.java
@@ -40,7 +40,7 @@
         LabelResourceService lrs = get(LabelResourceService.class);
         Collection<LabelResource> result =
                 lrs.applyFromGlobalPool(Long.parseLong(applyNum));
-        if (result.size() > 0) {
+        if (!result.isEmpty()) {
             for (Iterator<LabelResource> iterator = result.iterator(); iterator
                     .hasNext();) {
                 DefaultLabelResource defaultLabelResource = (DefaultLabelResource) iterator
diff --git a/cli/src/main/java/org/onosproject/cli/net/LabelApplyCommand.java b/cli/src/main/java/org/onosproject/cli/net/LabelApplyCommand.java
index 0ff7bed..dea152d 100644
--- a/cli/src/main/java/org/onosproject/cli/net/LabelApplyCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/net/LabelApplyCommand.java
@@ -45,7 +45,7 @@
         LabelResourceService lrs = get(LabelResourceService.class);
         Collection<LabelResource> result = lrs.applyFromDevicePool(DeviceId
                 .deviceId(deviceId), Long.parseLong(applyNum));
-        if (result.size() > 0) {
+        if (!result.isEmpty()) {
             for (Iterator<LabelResource> iterator = result.iterator(); iterator
                     .hasNext();) {
                 DefaultLabelResource defaultLabelResource = (DefaultLabelResource) iterator
diff --git a/core/api/src/main/java/org/onosproject/net/driver/DefaultDriver.java b/core/api/src/main/java/org/onosproject/net/driver/DefaultDriver.java
index c54ca46..7ed674b 100644
--- a/core/api/src/main/java/org/onosproject/net/driver/DefaultDriver.java
+++ b/core/api/src/main/java/org/onosproject/net/driver/DefaultDriver.java
@@ -99,7 +99,7 @@
                 }
             }));
         }
-        return new DefaultDriver(name, completeParents.size() > 0 ? completeParents : other.parents(),
+        return new DefaultDriver(name, !completeParents.isEmpty() ? completeParents : other.parents(),
                                  manufacturer, hwVersion, swVersion,
                                  ImmutableMap.copyOf(behaviours), properties.build());
     }
diff --git a/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java b/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java
index 623ece1..1fd3935 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java
@@ -498,7 +498,7 @@
 
         @Override
         public TrafficTreatment build() {
-            if (deferred.size() == 0 && immediate.size() == 0
+            if (deferred.isEmpty() && immediate.isEmpty()
                     && table == null && !clear) {
                 immediate();
                 noAction();
diff --git a/core/api/src/main/java/org/onosproject/net/mcast/McastRouteInfo.java b/core/api/src/main/java/org/onosproject/net/mcast/McastRouteInfo.java
index f8d232b..9a47817 100644
--- a/core/api/src/main/java/org/onosproject/net/mcast/McastRouteInfo.java
+++ b/core/api/src/main/java/org/onosproject/net/mcast/McastRouteInfo.java
@@ -62,7 +62,7 @@
     }
 
     public boolean isComplete() {
-        return ((sink.isPresent() || sinks.size() > 0) && source.isPresent());
+        return ((sink.isPresent() || !sinks.isEmpty()) && source.isPresent());
     }
 
     /**
diff --git a/core/api/src/main/java/org/onosproject/net/meter/DefaultMeter.java b/core/api/src/main/java/org/onosproject/net/meter/DefaultMeter.java
index e2e049d..f33c914 100644
--- a/core/api/src/main/java/org/onosproject/net/meter/DefaultMeter.java
+++ b/core/api/src/main/java/org/onosproject/net/meter/DefaultMeter.java
@@ -222,7 +222,7 @@
         public DefaultMeter build() {
             checkNotNull(deviceId, "Must specify a device");
             checkNotNull(bands, "Must have bands.");
-            checkArgument(bands.size() > 0, "Must have at least one band.");
+            checkArgument(!bands.isEmpty(), "Must have at least one band.");
             checkNotNull(appId, "Must have an application id");
             checkNotNull(id, "Must specify a meter id");
             return new DefaultMeter(deviceId, id, appId, unit, burst, bands);
diff --git a/core/api/src/main/java/org/onosproject/net/meter/DefaultMeterRequest.java b/core/api/src/main/java/org/onosproject/net/meter/DefaultMeterRequest.java
index 7168928..1ca4466 100644
--- a/core/api/src/main/java/org/onosproject/net/meter/DefaultMeterRequest.java
+++ b/core/api/src/main/java/org/onosproject/net/meter/DefaultMeterRequest.java
@@ -165,7 +165,7 @@
         private void validate() {
             checkNotNull(deviceId, "Must specify a device");
             checkNotNull(bands, "Must have bands.");
-            checkArgument(bands.size() > 0, "Must have at least one band.");
+            checkArgument(!bands.isEmpty(), "Must have at least one band.");
             checkNotNull(appId, "Must have an application id");
         }
 
diff --git a/core/api/src/main/java/org/onosproject/net/resource/ContinuousResourceId.java b/core/api/src/main/java/org/onosproject/net/resource/ContinuousResourceId.java
index 0222051..46237e0 100644
--- a/core/api/src/main/java/org/onosproject/net/resource/ContinuousResourceId.java
+++ b/core/api/src/main/java/org/onosproject/net/resource/ContinuousResourceId.java
@@ -93,7 +93,7 @@
 
     @Override
     public Optional<DiscreteResourceId> parent() {
-        if (components.size() == 0) {
+        if (components.isEmpty()) {
             return Optional.empty();
         }
         if (components.size() == 1) {
diff --git a/core/api/src/main/java/org/onosproject/ui/UiExtension.java b/core/api/src/main/java/org/onosproject/ui/UiExtension.java
index bc0dfc9..17201cb 100644
--- a/core/api/src/main/java/org/onosproject/ui/UiExtension.java
+++ b/core/api/src/main/java/org/onosproject/ui/UiExtension.java
@@ -165,7 +165,7 @@
          */
         public Builder(ClassLoader cl, List<UiView> views) {
             checkNotNull(cl, "Must provide a class loader");
-            checkArgument(views.size() > 0, "Must provide at least one view");
+            checkArgument(!views.isEmpty(), "Must provide at least one view");
             classLoader = cl;
             viewList = views;
         }
diff --git a/core/api/src/main/java/org/onosproject/ui/topo/NodeSelection.java b/core/api/src/main/java/org/onosproject/ui/topo/NodeSelection.java
index ce5680e..f906546 100644
--- a/core/api/src/main/java/org/onosproject/ui/topo/NodeSelection.java
+++ b/core/api/src/main/java/org/onosproject/ui/topo/NodeSelection.java
@@ -97,7 +97,7 @@
         Set<String> unmatched = findLinks(ids);
         unmatched = findDevices(unmatched);
         unmatched = findHosts(unmatched);
-        if (unmatched.size() > 0) {
+        if (!unmatched.isEmpty()) {
             log.debug("Skipping unmatched IDs {}", unmatched);
         }
 
diff --git a/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java b/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java
index 2bed282..8e0f0b7 100644
--- a/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java
+++ b/core/common/src/main/java/org/onosproject/codec/impl/RoleInfoCodec.java
@@ -54,7 +54,7 @@
         ArrayNode backups = context.mapper().createArrayNode();
         roleInfo.backups().forEach(backup -> backups.add(backup.id()));
 
-        if (roleInfo.backups().size() != 0) {
+        if (!roleInfo.backups().isEmpty()) {
             result.set(BACKUPS, backups);
         }
 
diff --git a/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java b/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
index 17df9c4..cd244ff 100644
--- a/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
+++ b/core/net/src/main/java/org/onosproject/net/flow/impl/FlowRuleManager.java
@@ -629,7 +629,7 @@
 
         @Override
         public synchronized void run() {
-            if (stages.size() > 0) {
+            if (!stages.isEmpty()) {
                 process(stages.remove(0));
             } else if (!hasFailed) {
                 fops.callback().onSuccess(fops);
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixLeaderElectorState.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixLeaderElectorState.java
index cb7d63a..369c191 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixLeaderElectorState.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/AtomixLeaderElectorState.java
@@ -449,7 +449,7 @@
                         .filter(r -> r.sessionId() != session.id())
                         .collect(Collectors.toList());
                 if (leader.sessionId() == session.id()) {
-                    if (updatedRegistrations.size() > 0) {
+                    if (!updatedRegistrations.isEmpty()) {
                         return new ElectionState(updatedRegistrations,
                                 updatedRegistrations.get(0),
                                 termCounter.get(),
@@ -474,7 +474,7 @@
                         .filter(r -> !r.nodeId().equals(nodeId))
                         .collect(Collectors.toList());
                 if (leader.nodeId().equals(nodeId)) {
-                    if (updatedRegistrations.size() > 0) {
+                    if (!updatedRegistrations.isEmpty()) {
                         return new ElectionState(updatedRegistrations,
                                 updatedRegistrations.get(0),
                                 termCounter.get(),
diff --git a/drivers/optical/src/main/java/org/onosproject/driver/optical/handshaker/OplinkRoadm.java b/drivers/optical/src/main/java/org/onosproject/driver/optical/handshaker/OplinkRoadm.java
index 99f2be3..273469b 100644
--- a/drivers/optical/src/main/java/org/onosproject/driver/optical/handshaker/OplinkRoadm.java
+++ b/drivers/optical/src/main/java/org/onosproject/driver/optical/handshaker/OplinkRoadm.java
@@ -277,7 +277,7 @@
     private OplinkPortAdjacency getNeighbor(OFExpPortAdjacency ad) {
         for (OFExpPortAdjacencyId adid : ad.getProperties()) {
             List<OFExpExtAdId> otns = adid.getAdId();
-            if (otns != null && otns.size() > 0) {
+            if (otns != null && !otns.isEmpty()) {
                 OFExpPortAdidOtn otn = (OFExpPortAdidOtn) otns.get(0);
                 // ITU-T G.7714 ETH MAC Format (in second 16 bytes of the following)
                 // |---------------------------------------------------------------------------|
diff --git a/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbControllerConfig.java b/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbControllerConfig.java
index 25210a2..4f93484 100644
--- a/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbControllerConfig.java
+++ b/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbControllerConfig.java
@@ -81,7 +81,7 @@
         List<OvsdbNodeId> nodeIds = ovsController.getNodeIds().stream()
                 .filter(nodeId -> nodeId.getIpAddress().equals(targetIp))
                 .collect(Collectors.toList());
-        if (nodeIds.size() == 0) {
+        if (nodeIds.isEmpty()) {
             //TODO decide what port?
             ovsController.connect(IpAddress.valueOf(targetIp),
                                   targetPort == null ? TpPort.tpPort(OvsdbConstant.OVSDBPORT) : targetPort);
@@ -92,9 +92,9 @@
                 .map(ovsController::getOvsdbClient)
                 .filter(cs -> cs.getBridges().stream().anyMatch(b -> dpidMatches(b, ofDeviceId)))
                 .collect(Collectors.toList());
-        checkState(clientServices.size() > 0, "No clientServices found");
+        checkState(!clientServices.isEmpty(), "No clientServices found");
         //FIXME add connection to management address if null --> done ?
-        return clientServices.size() > 0 ? clientServices.get(0) : null;
+        return !clientServices.isEmpty() ? clientServices.get(0) : null;
     }
 
     private static boolean dpidMatches(OvsdbBridge bridge, DeviceId deviceId) {
diff --git a/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbMirroringConfig.java b/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbMirroringConfig.java
index 9a1896e..58cf117 100644
--- a/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbMirroringConfig.java
+++ b/drivers/ovsdb/src/main/java/org/onosproject/drivers/ovsdb/OvsdbMirroringConfig.java
@@ -124,7 +124,7 @@
                 List<OvsdbNodeId> nodeIds = ovsController.getNodeIds().stream()
                         .filter(nodeID -> nodeID.getIpAddress().equals(targetIp))
                         .collect(Collectors.toList());
-                if (nodeIds.size() == 0) {
+                if (nodeIds.isEmpty()) {
                     //TODO decide what port?
                     ovsController.connect(IpAddress.valueOf(targetIp),
                                           targetPort == null ? TpPort.tpPort(OvsdbConstant.OVSDBPORT) : targetPort);
@@ -135,9 +135,9 @@
                         .map(ovsController::getOvsdbClient)
                         .filter(cs -> cs.getBridges().stream().anyMatch(b -> dpidMatches(b, deviceId)))
                         .collect(Collectors.toList());
-                checkState(clientServices.size() > 0, "No clientServices found");
+                checkState(!clientServices.isEmpty(), "No clientServices found");
                 //FIXME add connection to management address if null --> done ?
-                return clientServices.size() > 0 ? clientServices.get(0) : null;
+                return !clientServices.isEmpty() ? clientServices.get(0) : null;
             default:
                 log.warn("Unmanaged device type");
         }
diff --git a/incubator/net/src/main/java/org/onosproject/incubator/net/tunnel/impl/TunnelManager.java b/incubator/net/src/main/java/org/onosproject/incubator/net/tunnel/impl/TunnelManager.java
index a9582ab..9b8a2e7 100644
--- a/incubator/net/src/main/java/org/onosproject/incubator/net/tunnel/impl/TunnelManager.java
+++ b/incubator/net/src/main/java/org/onosproject/incubator/net/tunnel/impl/TunnelManager.java
@@ -209,7 +209,7 @@
                                               Annotations... annotations) {
         Collection<Tunnel> tunnels = store.borrowTunnel(consumerId, src,
                                                            dst, annotations);
-        if (tunnels == null || tunnels.size() == 0) {
+        if (tunnels == null || tunnels.isEmpty()) {
             Tunnel tunnel = new DefaultTunnel(null, src, dst, null, null, null,
                                               null, null, annotations);
             Set<ProviderId> ids = getProviders();
@@ -228,7 +228,7 @@
         Collection<Tunnel> tunnels = store.borrowTunnel(consumerId, src,
                                                            dst, type,
                                                            annotations);
-        if (tunnels == null || tunnels.size() == 0) {
+        if (tunnels == null || tunnels.isEmpty()) {
             Tunnel tunnel = new DefaultTunnel(null, src, dst, type, null, null,
                                               null, null, annotations);
             Set<ProviderId> ids = getProviders();
diff --git a/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkFlowRuleManager.java b/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkFlowRuleManager.java
index 31c1415..f6c6e2b 100644
--- a/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkFlowRuleManager.java
+++ b/incubator/net/src/main/java/org/onosproject/incubator/net/virtual/impl/VirtualNetworkFlowRuleManager.java
@@ -251,7 +251,7 @@
 
         @Override
         public synchronized void run() {
-            if (stages.size() > 0) {
+            if (!stages.isEmpty()) {
                 process(stages.remove(0));
             } else if (!hasFailed) {
                 fops.callback().onSuccess(fops);
diff --git a/incubator/store/src/main/java/org/onosproject/incubator/store/tunnel/impl/DistributedTunnelStore.java b/incubator/store/src/main/java/org/onosproject/incubator/store/tunnel/impl/DistributedTunnelStore.java
index 31452ac..0907643 100644
--- a/incubator/store/src/main/java/org/onosproject/incubator/store/tunnel/impl/DistributedTunnelStore.java
+++ b/incubator/store/src/main/java/org/onosproject/incubator/store/tunnel/impl/DistributedTunnelStore.java
@@ -307,7 +307,7 @@
         orderRelationship.put(appId, orderSet);
         TunnelKey key = TunnelKey.tunnelKey(src, dst);
         Set<TunnelId> idSet = srcAndDstKeyMap.get(key);
-        if (idSet == null || idSet.size() == 0) {
+        if (idSet == null || idSet.isEmpty()) {
             return Collections.emptySet();
         }
         Collection<Tunnel> tunnelSet = new HashSet<Tunnel>();
@@ -337,7 +337,7 @@
         orderRelationship.put(appId, orderSet);
         TunnelKey key = TunnelKey.tunnelKey(src, dst);
         Set<TunnelId> idSet = srcAndDstKeyMap.get(key);
-        if (idSet == null || idSet.size() == 0) {
+        if (idSet == null || idSet.isEmpty()) {
             return Collections.emptySet();
         }
         Collection<Tunnel> tunnelSet = new HashSet<Tunnel>();
@@ -364,7 +364,7 @@
         boolean isExist = orderSet.contains(order);
 
         Set<TunnelId> idSet = tunnelNameAsKeyMap.get(tunnelName);
-        if (idSet == null || idSet.size() == 0) {
+        if (idSet == null || idSet.isEmpty()) {
             return Collections.emptySet();
         }
         Collection<Tunnel> tunnelSet = new HashSet<Tunnel>();
@@ -447,7 +447,7 @@
         for (TunnelId id : tunnelIds) {
             result.add(tunnelIdAsKeyStore.get(id));
         }
-        return result.size() == 0 ? Collections.emptySet() : ImmutableSet
+        return result.isEmpty() ? Collections.emptySet() : ImmutableSet
                 .copyOf(result);
     }
 
@@ -462,7 +462,7 @@
         for (TunnelId id : tunnelIds) {
             result.add(tunnelIdAsKeyStore.get(id));
         }
-        return result.size() == 0 ? Collections.emptySet() : ImmutableSet
+        return result.isEmpty() ? Collections.emptySet() : ImmutableSet
                 .copyOf(result);
     }
 
diff --git a/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/As4Path.java b/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/As4Path.java
index d766f0d..50d63aa 100644
--- a/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/As4Path.java
+++ b/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/As4Path.java
@@ -171,7 +171,7 @@
         if ((as4pathSet != null) && (as4pathSeq != null)) {
             int iAsLenIndex = cb.writerIndex();
             cb.writeByte(0);
-            if (as4pathSeq.size() != 0) {
+            if (!as4pathSeq.isEmpty()) {
                 cb.writeByte(AsPath.ASPATH_SEQ_TYPE);
                 cb.writeByte(as4pathSeq.size());
 
diff --git a/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/AsPath.java b/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/AsPath.java
index f6442d9..db1eed6 100644
--- a/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/AsPath.java
+++ b/protocols/bgp/bgpio/src/main/java/org/onosproject/bgpio/types/AsPath.java
@@ -208,7 +208,7 @@
         if (isaspathSet()) {
             int iAsLenIndex = cb.writerIndex();
             cb.writeByte(0);
-            if (aspathSeq.size() != 0) {
+            if (!aspathSeq.isEmpty()) {
                 cb.writeByte(ASPATH_SEQ_TYPE);
                 cb.writeByte(aspathSeq.size());
 
diff --git a/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/Controller.java b/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/Controller.java
index 406d09c..ae9504b 100644
--- a/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/Controller.java
+++ b/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/Controller.java
@@ -127,7 +127,7 @@
         configPacket[1] = numberOfInterface;
         //First time configuration
         if (processes == null) {
-            if (isisProcesses.size() > 0) {
+            if (!isisProcesses.isEmpty()) {
                 processes = isisProcesses;
                 connectPeer();
             }
@@ -337,7 +337,7 @@
                 }
                 interfaceList.add(isisInterface);
             }
-            if (interfaceList.size() > 0) {
+            if (!interfaceList.isEmpty()) {
                 IsisProcess process = new DefaultIsisProcess();
                 process.setProcessId(jsonNode.path(IsisConstants.PROCESSESID).asText());
                 process.setIsisInterfaceList(interfaceList);
diff --git a/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/IsisMessageDecoder.java b/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/IsisMessageDecoder.java
index b75bc3f..43d95d8 100644
--- a/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/IsisMessageDecoder.java
+++ b/protocols/isis/ctl/src/main/java/org/onosproject/isis/controller/impl/IsisMessageDecoder.java
@@ -73,7 +73,7 @@
                 isisMessageList.add(message);
             }
         }
-        return (isisMessageList.size() > 0) ? isisMessageList : null;
+        return (!isisMessageList.isEmpty()) ? isisMessageList : null;
     }
 
     /**
diff --git a/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/tlv/NeighborForExtendedIs.java b/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/tlv/NeighborForExtendedIs.java
index f5cd03b..5c3bb2e 100644
--- a/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/tlv/NeighborForExtendedIs.java
+++ b/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/isispacket/tlv/NeighborForExtendedIs.java
@@ -134,7 +134,7 @@
         List<Byte> byteList = new ArrayList<>();
         byteList.addAll(IsisUtil.sourceAndLanIdToBytes(this.neighborId()));
         byteList.addAll(Bytes.asList(IsisUtil.convertToThreeBytes(this.metric())));
-        if (this.teSubTlv.size() > 0) {
+        if (!this.teSubTlv.isEmpty()) {
             for (TrafficEngineeringSubTlv trafficEngineeringSubTlv : this.teSubTlv) {
                 byteList.addAll(SubTlvToBytes.tlvToBytes(trafficEngineeringSubTlv));
             }
diff --git a/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/util/IsisUtil.java b/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/util/IsisUtil.java
index 80bd083..a385376 100644
--- a/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/util/IsisUtil.java
+++ b/protocols/isis/isisio/src/main/java/org/onosproject/isis/io/util/IsisUtil.java
@@ -423,7 +423,7 @@
         adjacencyStateTlv.setAdjacencyType((byte) IsisInterfaceState.DOWN.value());
         adjacencyStateTlv.setLocalCircuitId(Integer.parseInt(isisInterface.circuitId()));
         Set<MacAddress> neighbors = isisInterface.neighbors();
-        if (neighbors.size() > 0) {
+        if (!neighbors.isEmpty()) {
             IsisNeighbor neighbor = isisInterface.lookup(neighbors.iterator().next());
             adjacencyStateTlv.setAdjacencyType((byte) neighbor.interfaceState().value());
             adjacencyStateTlv.setNeighborSystemId(neighbor.neighborSystemId());
@@ -509,7 +509,7 @@
         areaAddressTlv.addAddress(isisInterface.areaAddress());
         l1L2HelloPdu.addTlv(areaAddressTlv);
         Set<MacAddress> neighbors = isisInterface.neighbors();
-        if (neighbors.size() > 0) {
+        if (!neighbors.isEmpty()) {
             List<MacAddress> neighborMacs = new ArrayList<>();
             for (MacAddress neighbor : neighbors) {
                 IsisNeighbor isisNeighbor = isisInterface.lookup(neighbor);
diff --git a/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfControllerImpl.java b/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfControllerImpl.java
index 83462ee..01f52dc 100644
--- a/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfControllerImpl.java
+++ b/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfControllerImpl.java
@@ -115,10 +115,10 @@
         try {
             List<OspfProcess> ospfProcesses = OspfConfigUtil.processes(processesNode);
             //if there is interface details then update configuration
-            if (ospfProcesses.size() > 0 &&
-                    ospfProcesses.get(0).areas() != null && ospfProcesses.get(0).areas().size() > 0 &&
+            if (!ospfProcesses.isEmpty() &&
+                    ospfProcesses.get(0).areas() != null && !ospfProcesses.get(0).areas().isEmpty() &&
                     ospfProcesses.get(0).areas().get(0) != null &&
-                    ospfProcesses.get(0).areas().get(0).ospfInterfaceList().size() > 0) {
+                    !ospfProcesses.get(0).areas().get(0).ospfInterfaceList().isEmpty()) {
                 ctrl.updateConfig(ospfProcesses);
             }
         } catch (Exception e) {
diff --git a/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfMessageDecoder.java b/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfMessageDecoder.java
index 1d6ae23..e459afa 100644
--- a/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfMessageDecoder.java
+++ b/protocols/ospf/ctl/src/main/java/org/onosproject/ospf/controller/impl/OspfMessageDecoder.java
@@ -66,6 +66,6 @@
                 ospfMessageList.add(message);
             }
         }
-        return (ospfMessageList.size() > 0) ? ospfMessageList : null;
+        return (!ospfMessageList.isEmpty()) ? ospfMessageList : null;
     }
 }
\ No newline at end of file
diff --git a/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/driver/DefaultOvsdbClient.java b/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/driver/DefaultOvsdbClient.java
index efaae8a..d5fed14 100644
--- a/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/driver/DefaultOvsdbClient.java
+++ b/protocols/ovsdb/api/src/main/java/org/onosproject/ovsdb/controller/driver/DefaultOvsdbClient.java
@@ -356,7 +356,7 @@
             OvsdbSet setPorts = (OvsdbSet) bridge.getPortsColumn().data();
             @SuppressWarnings("unchecked")
             Set<Uuid> ports = setPorts.set();
-            if (ports == null || ports.size() == 0) {
+            if (ports == null || ports.isEmpty()) {
                 log.warn("The port uuid is null");
                 return null;
             }
@@ -677,9 +677,9 @@
         mirrorBuilder.externalIds(mirror.externalIds());
         mirror = mirrorBuilder.build();
 
-        if (mirror.monitorDstPorts().size() == 0 &&
-                mirror.monitorSrcPorts().size() == 0 &&
-                mirror.monitorVlans().size() == 0) {
+        if (mirror.monitorDstPorts().isEmpty() &&
+                mirror.monitorSrcPorts().isEmpty() &&
+                mirror.monitorVlans().isEmpty()) {
             log.warn("Invalid monitoring data");
             return false;
         }
@@ -1332,7 +1332,7 @@
         OvsdbSet datapathIdSet = (OvsdbSet) bridge.getDatapathIdColumn().data();
         @SuppressWarnings("unchecked")
         Set<String> datapathIds = datapathIdSet.set();
-        if (datapathIds == null || datapathIds.size() == 0) {
+        if (datapathIds == null || datapathIds.isEmpty()) {
             return null;
         }
         String datapathId = (String) datapathIds.toArray()[0];
@@ -1347,7 +1347,7 @@
         OvsdbSet ofPortSet = (OvsdbSet) intf.getOpenFlowPortColumn().data();
         @SuppressWarnings("unchecked")
         Set<Integer> ofPorts = ofPortSet.set();
-        if (ofPorts == null || ofPorts.size() <= 0) {
+        if (ofPorts == null || ofPorts.isEmpty()) {
             log.debug("The ofport is null in {}", intf.getName());
             return -1;
         }
diff --git a/protocols/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java b/protocols/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java
index 04199e2..8258a74 100644
--- a/protocols/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java
+++ b/protocols/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java
@@ -342,7 +342,7 @@
         OvsdbSet ofPortSet = (OvsdbSet) intf.getOpenFlowPortColumn().data();
         @SuppressWarnings("unchecked")
         Set<Integer> ofPorts = ofPortSet.set();
-        while (ofPorts == null || ofPorts.size() <= 0) {
+        while (ofPorts == null || ofPorts.isEmpty()) {
             log.debug("The ofport is null in {}", intf.getName());
             return -1;
         }
@@ -374,7 +374,7 @@
         OvsdbSet dpidSet = (OvsdbSet) bridge.getDatapathIdColumn().data();
         @SuppressWarnings("unchecked")
         Set<String> dpids = dpidSet.set();
-        if (dpids == null || dpids.size() == 0) {
+        if (dpids == null || dpids.isEmpty()) {
             return 0;
         }
         return stringToLong((String) dpids.toArray()[0]);
diff --git a/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/BasicPceccHandler.java b/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/BasicPceccHandler.java
index 90b8ea0..9d65a16 100644
--- a/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/BasicPceccHandler.java
+++ b/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/BasicPceccHandler.java
@@ -153,7 +153,7 @@
         checkNotNull(pceStore, PCE_STORE_NULL);
 
         List<Link> linkList = tunnel.path().links();
-        if ((linkList != null) && (linkList.size() > 0)) {
+        if ((linkList != null) && (!linkList.isEmpty())) {
             // Sequence through reverse order to push local labels into devices
             // Generation of labels from egress to ingress
             for (ListIterator<Link> iterator = linkList.listIterator(linkList.size()); iterator.hasPrevious();) {
@@ -161,7 +161,7 @@
                 DeviceId dstDeviceId = link.dst().deviceId();
                 DeviceId srcDeviceId = link.src().deviceId();
                 labelRscList = labelRsrcService.applyFromDevicePool(dstDeviceId, applyNum);
-                if ((labelRscList != null) && (labelRscList.size() > 0)) {
+                if ((labelRscList != null) && (!labelRscList.isEmpty())) {
                     // Link label value is taken from destination device local pool.
                     // [X]OUT---link----IN[Y]OUT---link-----IN[Z] where X, Y and Z are nodes.
                     // Link label value is used as OUT and IN for both ends
@@ -228,7 +228,7 @@
        boolean srcDeviceUpdated = false;
 
        List<LspLocalLabelInfo> lspLabelInfoList = pceStore.getTunnelInfo(tunnel.tunnelId());
-       if ((lspLabelInfoList != null) && (lspLabelInfoList.size() > 0)) {
+       if ((lspLabelInfoList != null) && (!lspLabelInfoList.isEmpty())) {
            for (int i = 0; i < lspLabelInfoList.size(); ++i) {
                LspLocalLabelInfo lspLocalLabelInfo =
                        lspLabelInfoList.get(i);
@@ -299,7 +299,7 @@
 
        Multimap<DeviceId, LabelResource> release = ArrayListMultimap.create();
        List<LspLocalLabelInfo> lspLocalLabelInfoList = pceStore.getTunnelInfo(tunnel.tunnelId());
-       if ((lspLocalLabelInfoList != null) && (lspLocalLabelInfoList.size() > 0)) {
+       if ((lspLocalLabelInfoList != null) && (!lspLocalLabelInfoList.isEmpty())) {
            for (Iterator<LspLocalLabelInfo> iterator = lspLocalLabelInfoList.iterator(); iterator.hasNext();) {
                LspLocalLabelInfo lspLocalLabelInfo = iterator.next();
                DeviceId deviceId = lspLocalLabelInfo.deviceId();
diff --git a/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/PceccSrTeBeHandler.java b/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/PceccSrTeBeHandler.java
index 88e3b14..c6dad5a 100644
--- a/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/PceccSrTeBeHandler.java
+++ b/protocols/pcep/ctl/src/main/java/org/onosproject/pcep/controller/impl/PceccSrTeBeHandler.java
@@ -191,7 +191,7 @@
         // The specificDeviceId is the new device and is not there in the pce store.
         // So, first generate its label and configure label and its lsr-id to it.
         Collection<LabelResource> result = labelRsrcService.applyFromGlobalPool(applyNum);
-        if (result.size() > 0) {
+        if (!result.isEmpty()) {
             // Only one element (label-id) to retrieve
             Iterator<LabelResource> iterator = result.iterator();
             DefaultLabelResource defaultLabelResource = (DefaultLabelResource) iterator.next();
@@ -338,7 +338,7 @@
         // Allocate adjacency label to a link from label manager.
         // Take label from source device pool to allocate.
         labelList = labelRsrcService.applyFromDevicePool(srcDeviceId, applyNum);
-        if (labelList.size() <= 0) {
+        if (labelList.isEmpty()) {
             log.error("Unable to allocate label to a device id {}.", srcDeviceId.toString());
             return false;
         }
@@ -427,7 +427,7 @@
         // Label stack is linked list to make labels in order.
         List<LabelResourceId> labelStack = new LinkedList<>();
         List<Link> linkList = path.links();
-        if ((linkList != null) && (linkList.size() > 0)) {
+        if ((linkList != null) && (!linkList.isEmpty())) {
             // Path: [x] ---- [y] ---- [z]
             // For other than last link, add only source[x] device label.
             // For the last link, add both source[y] and destination[z] device labels.
diff --git a/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpConfiguration.java b/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpConfiguration.java
index d34c80e..f567e8d 100644
--- a/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpConfiguration.java
+++ b/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpConfiguration.java
@@ -87,7 +87,7 @@
             TreeMap<String, BgpPeerCfg> displayPeerTree = bgpCfg.getPeerTree();
             Set<String> peerKey = displayPeerTree.keySet();
             if (peer != null) {
-                if (peerKey.size() > 0) {
+                if (!peerKey.isEmpty()) {
                     for (String peerIdKey : peerKey) {
                         bgpPeerCfg = displayPeerTree.get(peerIdKey);
                         bgpConnectPeer = bgpPeerCfg.connectPeer();
@@ -101,7 +101,7 @@
                     }
                 }
             } else {
-                if (peerKey.size() > 0) {
+                if (!peerKey.isEmpty()) {
                     for (String peerIdKey : peerKey) {
                         bgpPeerCfg = displayPeerTree.get(peerIdKey);
                         bgpConnectPeer = bgpPeerCfg.connectPeer();
diff --git a/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpExceptions.java b/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpExceptions.java
index 2f129ba..4a70556 100644
--- a/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpExceptions.java
+++ b/providers/bgp/cli/src/main/java/org/onosproject/bgp/cli/BgpExceptions.java
@@ -64,7 +64,7 @@
             this.bgpController = get(BgpController.class);
             Map<String, List<String>> activeSessionExceptionMap = bgpController.activeSessionMap();
             activeSessionExceptionkeySet = activeSessionExceptionMap.keySet();
-            if (activeSessionExceptionkeySet.size() > 0) {
+            if (!activeSessionExceptionkeySet.isEmpty()) {
                 if (peerId != null) {
                     if (activeSessionExceptionkeySet.contains(peerId)) {
                         for (String peerIdKey : activeSessionExceptionkeySet) {
@@ -76,7 +76,7 @@
                     }
                 } else {
                     activeSessionExceptionkeySet = activeSessionExceptionMap.keySet();
-                    if (activeSessionExceptionkeySet.size() > 0) {
+                    if (!activeSessionExceptionkeySet.isEmpty()) {
                         for (String peerId : activeSessionExceptionkeySet) {
                             print("PeerId = %s, Exception = %s ", peerId, activeSessionExceptionMap.get(peerId));
                         }
@@ -93,7 +93,7 @@
             this.bgpController = get(BgpController.class);
             Map<String, List<String>> closedSessionExceptionMap = bgpController.closedSessionMap();
             closedSessionExceptionKeySet = closedSessionExceptionMap.keySet();
-            if (closedSessionExceptionKeySet.size() > 0) {
+            if (!closedSessionExceptionKeySet.isEmpty()) {
                 if (peerId != null) {
                     if (closedSessionExceptionKeySet.contains(peerId)) {
                         for (String peerIdKey : closedSessionExceptionKeySet) {
@@ -105,7 +105,7 @@
                     }
                 } else {
                     closedSessionExceptionKeySet = closedSessionExceptionMap.keySet();
-                    if (closedSessionExceptionKeySet.size() > 0) {
+                    if (!closedSessionExceptionKeySet.isEmpty()) {
                         for (String peerId : closedSessionExceptionKeySet) {
                             print("PeerId = %s, Exception = %s", peerId, closedSessionExceptionMap.get(peerId));
                         }
diff --git a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
index c1e2843..9c3ca0f 100644
--- a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
+++ b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
@@ -713,7 +713,7 @@
          */
         private PortDescription buildPortDescription(PortDescPropertyType ptype, OFPortOptical port,
                 OpenFlowOpticalSwitch opsw) {
-            checkArgument(port.getDesc().size() >= 1);
+            checkArgument(!port.getDesc().isEmpty());
 
             // Minimally functional fixture. This needs to be fixed as we add better support.
             PortNumber portNo = PortNumber.portNumber(port.getPortNo().getPortNumber());
@@ -790,7 +790,7 @@
             // Use the alias name if it's available
             String name = port.getName();
             List<OFCalientPortDescProp> props = port.getProperties();
-            if (props != null && props.size() > 0) {
+            if (props != null && !props.isEmpty()) {
                 OFCalientPortDescPropOptical propOptical = (OFCalientPortDescPropOptical) props.get(0);
                 if (propOptical != null) {
                     name = propOptical.getInAlias();
diff --git a/providers/openflow/flow/src/main/java/org/onosproject/provider/of/flow/impl/FlowModBuilderVer13.java b/providers/openflow/flow/src/main/java/org/onosproject/provider/of/flow/impl/FlowModBuilderVer13.java
index 44b839b..e63fa69 100644
--- a/providers/openflow/flow/src/main/java/org/onosproject/provider/of/flow/impl/FlowModBuilderVer13.java
+++ b/providers/openflow/flow/src/main/java/org/onosproject/provider/of/flow/impl/FlowModBuilderVer13.java
@@ -131,10 +131,10 @@
         if (treatment.clearedDeferred()) {
             instructions.add(factory().instructions().clearActions());
         }
-        if (immediateActions.size() > 0) {
+        if (!immediateActions.isEmpty()) {
             instructions.add(factory().instructions().applyActions(immediateActions));
         }
-        if (deferredActions.size() > 0) {
+        if (!deferredActions.isEmpty()) {
             instructions.add(factory().instructions().writeActions(deferredActions));
         }
         if (treatment.tableTransition() != null) {
@@ -172,13 +172,13 @@
         List<OFInstruction> instructions = Lists.newLinkedList();
 
 
-        if (immediateActions.size() > 0) {
+        if (!immediateActions.isEmpty()) {
             instructions.add(factory().instructions().applyActions(immediateActions));
         }
         if (treatment.clearedDeferred()) {
             instructions.add(factory().instructions().clearActions());
         }
-        if (deferredActions.size() > 0) {
+        if (!deferredActions.isEmpty()) {
             instructions.add(factory().instructions().writeActions(deferredActions));
         }
         if (treatment.tableTransition() != null) {
diff --git a/providers/openflow/group/src/main/java/org/onosproject/provider/of/group/impl/GroupBucketEntryBuilder.java b/providers/openflow/group/src/main/java/org/onosproject/provider/of/group/impl/GroupBucketEntryBuilder.java
index 1ba438d..58cf18e 100644
--- a/providers/openflow/group/src/main/java/org/onosproject/provider/of/group/impl/GroupBucketEntryBuilder.java
+++ b/providers/openflow/group/src/main/java/org/onosproject/provider/of/group/impl/GroupBucketEntryBuilder.java
@@ -119,7 +119,7 @@
         TrafficTreatment.Builder builder = DefaultTrafficTreatment.builder();
 
         // If this is a drop rule
-        if (actions.size() == 0) {
+        if (actions.isEmpty()) {
             builder.drop();
             return builder.build();
         }
diff --git a/providers/openflow/meter/src/main/java/org/onosproject/provider/of/meter/impl/MeterModBuilder.java b/providers/openflow/meter/src/main/java/org/onosproject/provider/of/meter/impl/MeterModBuilder.java
index 5d2a101..406337b 100644
--- a/providers/openflow/meter/src/main/java/org/onosproject/provider/of/meter/impl/MeterModBuilder.java
+++ b/providers/openflow/meter/src/main/java/org/onosproject/provider/of/meter/impl/MeterModBuilder.java
@@ -155,6 +155,6 @@
     private void validate() {
         checkNotNull(id, "id cannot be null");
         checkNotNull(bands, "Must have bands");
-        checkArgument(bands.size() > 0, "Must have at lease one band");
+        checkArgument(!bands.isEmpty(), "Must have at lease one band");
     }
 }
diff --git a/providers/pcep/cli/src/main/java/org/onosproject/pcep/cli/PcepSessionCommand.java b/providers/pcep/cli/src/main/java/org/onosproject/pcep/cli/PcepSessionCommand.java
index 420dd0c..f7407ec 100644
--- a/providers/pcep/cli/src/main/java/org/onosproject/pcep/cli/PcepSessionCommand.java
+++ b/providers/pcep/cli/src/main/java/org/onosproject/pcep/cli/PcepSessionCommand.java
@@ -93,7 +93,7 @@
             pcepSessionKeySet = pcepSessionMap.keySet();
             pcepSessionIdKeySet = pcepSessionIdMap.keySet();
             if (peer != null) {
-                if (pcepSessionKeySet.size() > 0) {
+                if (!pcepSessionKeySet.isEmpty()) {
                     if (pcepSessionKeySet.contains(peer)) {
                         for (String pcepSessionPeer : pcepSessionKeySet) {
                             if (pcepSessionPeer.equals(peer)) {
@@ -116,7 +116,7 @@
                     }
                 }
             } else {
-                if (pcepSessionKeySet.size() > 0) {
+                if (!pcepSessionKeySet.isEmpty()) {
                     for (String pcepSessionPeer : pcepSessionKeySet) {
                         for (String pcepSessionId : pcepSessionIdKeySet) {
                             if (pcepSessionId.equals(pcepSessionPeer)) {
@@ -143,7 +143,7 @@
             this.pcepClientController = get(PcepClientController.class);
             Map<String, List<String>> pcepSessionFailureReasonMap = pcepClientController.getPcepExceptions();
             pcepSessionFailurekeySet = pcepSessionFailureReasonMap.keySet();
-            if (pcepSessionFailurekeySet.size() > 0) {
+            if (!pcepSessionFailurekeySet.isEmpty()) {
                 if (peer != null) {
                     if (pcepSessionFailurekeySet.contains(peer)) {
                         for (String pcepSessionPeerId : pcepSessionFailurekeySet) {
@@ -158,7 +158,7 @@
 
                 } else {
                     pcepSessionFailurekeySet = pcepSessionFailureReasonMap.keySet();
-                    if (pcepSessionFailurekeySet.size() > 0) {
+                    if (!pcepSessionFailurekeySet.isEmpty()) {
                         for (String pcepSessionPeerId : pcepSessionFailurekeySet) {
                             pcepSessionExceptions = pcepSessionFailureReasonMap.get(pcepSessionPeerId);
                             print("PeerId = %s, FailureReason = %s", pcepSessionPeerId, pcepSessionExceptions);
@@ -181,7 +181,7 @@
             this.pcepClientController = get(PcepClientController.class);
             Map<Integer, Integer> pcepErrorMsgMap = pcepClientController.getPcepErrorMsg();
             pcepErrorMsgKey = pcepErrorMsgMap.keySet();
-            if (pcepErrorMsgKey.size() > 0) {
+            if (!pcepErrorMsgKey.isEmpty()) {
                 for (Integer errorType : pcepErrorMsgKey) {
                     pcepErrorValue = pcepErrorMsgMap.get(errorType);
                     pcepErrorType = PcepErrorType.values()[errorType];
diff --git a/providers/pcep/tunnel/src/main/java/org/onosproject/provider/pcep/tunnel/impl/PcepTunnelProvider.java b/providers/pcep/tunnel/src/main/java/org/onosproject/provider/pcep/tunnel/impl/PcepTunnelProvider.java
index 767d026..caa317d 100644
--- a/providers/pcep/tunnel/src/main/java/org/onosproject/provider/pcep/tunnel/impl/PcepTunnelProvider.java
+++ b/providers/pcep/tunnel/src/main/java/org/onosproject/provider/pcep/tunnel/impl/PcepTunnelProvider.java
@@ -720,7 +720,7 @@
     // Creates a path that leads through the given devices.
     private Path createPath(List<PcepHopNodeDescription> hopList,
                             PathType pathtype, PathState pathState) {
-        if (hopList == null || hopList.size() == 0) {
+        if (hopList == null || hopList.isEmpty()) {
             return null;
         }
         List<Link> links = new ArrayList<>();
@@ -947,7 +947,7 @@
             llSubObjects = createPcepPath(path);
         }
 
-        if (llSubObjects == null || llSubObjects.size() == 0) {
+        if (llSubObjects == null || llSubObjects.isEmpty()) {
             log.error("There is no link information to create tunnel");
             return null;
         }
@@ -1053,7 +1053,7 @@
 
             LinkedList<PcInitiatedLspRequest> llPcInitiatedLspRequestList = createPcInitiatedLspReqList(tunnel, path,
                                                                                                         pc, srpId);
-            if (llPcInitiatedLspRequestList == null || llPcInitiatedLspRequestList.size() == 0) {
+            if (llPcInitiatedLspRequestList == null || llPcInitiatedLspRequestList.isEmpty()) {
                 log.error("Failed to create PcInitiatedLspRequestList");
                 return;
             }
@@ -1735,7 +1735,7 @@
             checkNotNull(eroObj);
             List<Object> subObjList = new ArrayList<>();
             LinkedList<PcepValueType> llSubObj = eroObj.getSubObjects();
-            if (0 == llSubObj.size()) {
+            if (llSubObj.isEmpty()) {
                 log.error("ERO in report message does not have hop information");
                 return new ArrayList<>();
             }
diff --git a/utils/misc/src/main/java/org/onlab/graph/KShortestPathsSearch.java b/utils/misc/src/main/java/org/onlab/graph/KShortestPathsSearch.java
index 09735b4..c07b00a 100644
--- a/utils/misc/src/main/java/org/onlab/graph/KShortestPathsSearch.java
+++ b/utils/misc/src/main/java/org/onlab/graph/KShortestPathsSearch.java
@@ -58,7 +58,7 @@
         DijkstraGraphSearch<V, E> dijkstraSearch = new DijkstraGraphSearch<>();
         Set<Path<V, E>> dijkstraResults = dijkstraSearch.search(originalGraph, src, dst, modifiedWeighter, 1).paths();
         //Checks if the dst was reachable
-        if (dijkstraResults.size() == 0) {
+        if (dijkstraResults.isEmpty()) {
             log.warn("No path was found.");
             return result;
         }
@@ -84,7 +84,7 @@
                 }
 
                 dijkstraResults = dijkstraSearch.search(originalGraph, spurNode, dst, modifiedWeighter, 1).paths();
-                if (dijkstraResults.size() != 0) {
+                if (!dijkstraResults.isEmpty()) {
                     Path<V, E> spurPath = dijkstraResults.iterator().next();
                     List<E> totalPath = new ArrayList<>(rootPathEdgeList);
                     spurPath.edges().forEach(e -> totalPath.add(e));
diff --git a/utils/misc/src/main/java/org/onlab/graph/SrlgGraphSearch.java b/utils/misc/src/main/java/org/onlab/graph/SrlgGraphSearch.java
index e90b9f0..5ac35a0 100644
--- a/utils/misc/src/main/java/org/onlab/graph/SrlgGraphSearch.java
+++ b/utils/misc/src/main/java/org/onlab/graph/SrlgGraphSearch.java
@@ -184,7 +184,7 @@
         public double fitness() {
             Set<Path<V, E>> paths1 = findShortestPathFromSubset(subset).paths();
             Set<Path<V, E>> paths2 = findShortestPathFromSubset(not).paths();
-            if (paths1.size() == 0 || paths2.size() == 0) {
+            if (paths1.isEmpty() || paths2.isEmpty()) {
                 return INF;
             }
             return paths1.iterator().next().cost() + paths2.iterator().next().cost();
diff --git a/utils/misc/src/main/java/org/onlab/graph/SuurballeGraphSearch.java b/utils/misc/src/main/java/org/onlab/graph/SuurballeGraphSearch.java
index f3d0e62..f517d5a 100644
--- a/utils/misc/src/main/java/org/onlab/graph/SuurballeGraphSearch.java
+++ b/utils/misc/src/main/java/org/onlab/graph/SuurballeGraphSearch.java
@@ -56,7 +56,7 @@
 
         //choose an arbitrary shortest path to run Suurballe on
         Path<V, E> shortPath = null;
-        if (firstDijkstraS.paths().size() == 0) {
+        if (firstDijkstraS.paths().isEmpty()) {
             return firstDijkstraS;
         }
 
@@ -88,7 +88,7 @@
                     .search(gt, src, dst, modified, ALL_PATHS);
 
             Path<V, E> residualShortPath = null;
-            if (secondDijkstra.paths().size() == 0) {
+            if (secondDijkstra.paths().isEmpty()) {
                 result.dpps.add(new DisjointPathPair<>(shortPath, null));
                 continue;
             }
diff --git a/web/api/src/main/java/org/onosproject/rest/resources/NetworkConfigWebResource.java b/web/api/src/main/java/org/onosproject/rest/resources/NetworkConfigWebResource.java
index 39c9dd3..29291cd 100644
--- a/web/api/src/main/java/org/onosproject/rest/resources/NetworkConfigWebResource.java
+++ b/web/api/src/main/java/org/onosproject/rest/resources/NetworkConfigWebResource.java
@@ -204,7 +204,7 @@
                     errorMsgs.addAll(consumeJson(service, (ObjectNode) root.path(sk),
                                                  service.getSubjectFactory(sk)));
                 });
-        if (errorMsgs.size() > 0) {
+        if (!errorMsgs.isEmpty()) {
             return Response.status(MULTI_STATUS_RESPONE).entity(produceErrorJson(errorMsgs)).build();
         }
         return Response.ok().build();
@@ -227,7 +227,7 @@
         NetworkConfigService service = get(NetworkConfigService.class);
         ObjectNode root = (ObjectNode) mapper().readTree(request);
         List<String> errorMsgs = consumeJson(service, root, service.getSubjectFactory(subjectClassKey));
-        if (errorMsgs.size() > 0) {
+        if (!errorMsgs.isEmpty()) {
             return Response.status(MULTI_STATUS_RESPONE).entity(produceErrorJson(errorMsgs)).build();
         }
         return Response.ok().build();
@@ -254,7 +254,7 @@
         List<String> errorMsgs = consumeSubjectJson(service, root,
                                  service.getSubjectFactory(subjectClassKey).createSubject(subjectKey),
                                  subjectClassKey);
-        if (errorMsgs.size() > 0) {
+        if (!errorMsgs.isEmpty()) {
             return Response.status(MULTI_STATUS_RESPONE).entity(produceErrorJson(errorMsgs)).build();
         }
         return Response.ok().build();