diff --git a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/pwaas/L2TunnelHandler.java b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/pwaas/L2TunnelHandler.java
index 3a89a21..044ad41 100644
--- a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/pwaas/L2TunnelHandler.java
+++ b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/pwaas/L2TunnelHandler.java
@@ -129,7 +129,7 @@
 
         private final int code;
         private final String description;
-        public int nextId;
+        protected int nextId;
 
         Result(int code, String description) {
             this.code = code;
diff --git a/drivers/server/src/main/java/org/onosproject/drivers/server/BasicServerDriver.java b/drivers/server/src/main/java/org/onosproject/drivers/server/BasicServerDriver.java
index fa8ee63..ba16a3a 100644
--- a/drivers/server/src/main/java/org/onosproject/drivers/server/BasicServerDriver.java
+++ b/drivers/server/src/main/java/org/onosproject/drivers/server/BasicServerDriver.java
@@ -160,7 +160,7 @@
         try {
             result = jsonNode.get(attribute).asText();
         } catch (Exception ex) {
-            throw new RuntimeException(
+            throw new IllegalArgumentException(
                 "Failed to read JSON attribute: " + attribute
             );
         }
diff --git a/drivers/server/src/main/java/org/onosproject/drivers/server/ServerDevicesDiscovery.java b/drivers/server/src/main/java/org/onosproject/drivers/server/ServerDevicesDiscovery.java
index 3adb0b4..694320d 100644
--- a/drivers/server/src/main/java/org/onosproject/drivers/server/ServerDevicesDiscovery.java
+++ b/drivers/server/src/main/java/org/onosproject/drivers/server/ServerDevicesDiscovery.java
@@ -305,7 +305,7 @@
             String portTypeStr = get(nn, NIC_PARAM_PORT_TYPE);
             Port.Type portType = PORT_TYPE_MAP.get(portTypeStr);
             if (portType == null) {
-                throw new RuntimeException(
+                throw new IllegalArgumentException(
                     portTypeStr + " is not a valid port type for NIC " + nicId
                 );
             }
@@ -313,7 +313,7 @@
             String hwAddr      = get(nn, NIC_PARAM_HW_ADDR);
             JsonNode tagNode   = nicObjNode.path(NIC_PARAM_RX_FILTER);
             if (tagNode == null) {
-                throw new RuntimeException(
+                throw new IllegalArgumentException(
                     "The Rx filters of NIC " + nicId + " are not reported"
                 );
             }
@@ -723,7 +723,7 @@
 
         // And verify that this is the traffic class we want to monitor
         if (!id.equals(tcId.toString())) {
-            throw new RuntimeException(
+            throw new IllegalStateException(
                 "Failed to retrieve monitoring data for traffic class " + tcId +
                 ". Traffic class ID does not agree."
             );