Sonar suggestions - fixes to potential null pointer dereferences

Change-Id: I4e350a9d72a9322971d5d4f831f1bdf167986b87
diff --git a/drivers/default/src/main/java/org/onosproject/driver/pipeline/PicaPipeline.java b/drivers/default/src/main/java/org/onosproject/driver/pipeline/PicaPipeline.java
index 6c73693..ef79ee3 100644
--- a/drivers/default/src/main/java/org/onosproject/driver/pipeline/PicaPipeline.java
+++ b/drivers/default/src/main/java/org/onosproject/driver/pipeline/PicaPipeline.java
@@ -381,7 +381,8 @@
             return;
         }
 
-        EthCriterion e = null; VlanIdCriterion v = null;
+        EthCriterion e = null;
+        VlanIdCriterion v = null;
         Collection<IPCriterion> ips = new ArrayList<IPCriterion>();
         // convert filtering conditions for switch-intfs into flowrules
         FlowRuleOperations.Builder ops = FlowRuleOperations.builder();
@@ -399,6 +400,12 @@
             }
         }
 
+        if (v == null || e == null) {
+            log.warn("Pica Pipeline ETH_DST and/or VLAN_ID not specified");
+            fail(filt, ObjectiveError.BADPARAMS);
+            return;
+        }
+
         // cache for later use
         Filter filter = new Filter(p, e, v, ips);
         filters.add(filter);