SONAR suggestion - generic exceptions

Replace uses of generic RuntimeException
with more appropriate unchecked exceptions

Change-Id: If283743c2cf7252b8d280bdb788708ebbe57da9d
diff --git a/apps/l3vpn/src/main/java/org/onosproject/l3vpn/netl3vpn/impl/NetL3VpnManager.java b/apps/l3vpn/src/main/java/org/onosproject/l3vpn/netl3vpn/impl/NetL3VpnManager.java
index 0cb86ab..45e9f9b 100644
--- a/apps/l3vpn/src/main/java/org/onosproject/l3vpn/netl3vpn/impl/NetL3VpnManager.java
+++ b/apps/l3vpn/src/main/java/org/onosproject/l3vpn/netl3vpn/impl/NetL3VpnManager.java
@@ -240,7 +240,7 @@
             value = l3VpnIdGen.getNewId();
         }
         if (value > ID_LIMIT) {
-            throw new RuntimeException(ID_LIMIT_EXCEEDED);
+            throw new IllegalStateException(ID_LIMIT_EXCEEDED);
         }
         return CONS_HUNDRED + String.valueOf(value);
     }