ONOS-6776 ImmutableMap.of use error

Change-Id: Ia479eebd7bfc11e91242cb65fa048c084d5633e9
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java
index 0791f3a..3069e27 100644
--- a/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java
@@ -47,13 +47,14 @@
  */
 final class CriterionTranslatorHelper {
 
-    private static final Map<Class<? extends Criterion>, CriterionTranslator> TRANSLATORS = ImmutableMap.of(
+    private static final Map<Class<? extends Criterion>, CriterionTranslator> TRANSLATORS =
             // Add here new CriterionTranslator implementations.
-            PortCriterion.class, new PortCriterionTranslator(),
-            EthCriterion.class, new EthCriterionTranslator(),
-            EthTypeCriterion.class, new EthTypeCriterionTranslator(),
-            IPCriterion.class, new IpCriterionTranslator()
-    );
+            new ImmutableMap.Builder<Class<? extends Criterion>, CriterionTranslator>()
+                    .put(PortCriterion.class, new PortCriterionTranslator())
+                    .put(EthCriterion.class, new EthCriterionTranslator())
+                    .put(EthTypeCriterion.class, new EthTypeCriterionTranslator())
+                    .put(IPCriterion.class, new IpCriterionTranslator())
+                    .build();
 
     private CriterionTranslatorHelper() {
         // Hides constructor.