Constructor is needed by the serializer

Change-Id: I090c082ded1a7f9f2c9d877866b252939d6283ad
diff --git a/core/api/src/main/java/org/onosproject/core/DefaultApplication.java b/core/api/src/main/java/org/onosproject/core/DefaultApplication.java
index 1eb83b4..2df2f8f 100644
--- a/core/api/src/main/java/org/onosproject/core/DefaultApplication.java
+++ b/core/api/src/main/java/org/onosproject/core/DefaultApplication.java
@@ -55,8 +55,20 @@
      * Default constructor is hidden to prevent calls to new.
      */
     private DefaultApplication() {
-        // should never happen
-        throw new UnsupportedOperationException();
+        appId = null;
+        version = null;
+        title = null;
+        description = null;
+        category = null;
+        url = null;
+        readme = null;
+        icon = null;
+        origin = null;
+        role = null;
+        permissions = null;
+        featuresRepo = Optional.empty();
+        features = ImmutableList.of();
+        requiredApps = ImmutableList.of();
     }
 
     /**
diff --git a/core/api/src/main/java/org/onosproject/net/behaviour/MirroringStatistics.java b/core/api/src/main/java/org/onosproject/net/behaviour/MirroringStatistics.java
index 633995f..b9aae84 100644
--- a/core/api/src/main/java/org/onosproject/net/behaviour/MirroringStatistics.java
+++ b/core/api/src/main/java/org/onosproject/net/behaviour/MirroringStatistics.java
@@ -34,8 +34,9 @@
      * Hide private constructor to prevent calls to new().
      */
     private MirroringStatistics() {
-        // This should never happen
-        throw new UnsupportedOperationException();
+        mirroringName = null;
+        txBytes = 0;
+        txPackets = 0;
     }
 
     /**