Bump ONOS to 2.2 and build with Java 11

This app relies on dynamic OSGi @Reference. New Karaf demands volatile
fields, which required different handling of service bind/unbind events.

Change-Id: I215f7ca5cbded3acd9c440fe723f6f21d77f9ed5
diff --git a/src/main/java/org/opencord/kafka/impl/KafkaIntegration.java b/src/main/java/org/opencord/kafka/impl/KafkaIntegration.java
index 0720a86..7dc2c35 100644
--- a/src/main/java/org/opencord/kafka/impl/KafkaIntegration.java
+++ b/src/main/java/org/opencord/kafka/impl/KafkaIntegration.java
@@ -16,12 +16,11 @@
 package org.opencord.kafka.impl;
 
 import com.fasterxml.jackson.databind.JsonNode;
-import org.apache.felix.scr.annotations.Activate;
-import org.apache.felix.scr.annotations.Component;
-import org.apache.felix.scr.annotations.Deactivate;
-import org.apache.felix.scr.annotations.Reference;
-import org.apache.felix.scr.annotations.ReferenceCardinality;
-import org.apache.felix.scr.annotations.Service;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Deactivate;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
 import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.ProducerRecord;
 import org.apache.kafka.common.serialization.StringSerializer;
@@ -48,7 +47,6 @@
 /**
  * Sends events to a Kafka event bus.
  */
-@Service
 @Component(immediate = true)
 public class KafkaIntegration implements EventBusService {
 
@@ -61,13 +59,13 @@
 
     private Boolean kafkaStarted = false;
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected CoreService coreService;
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected ClusterService clusterService;
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected NetworkConfigRegistry configRegistry;
 
     private static StringSerializer stringSerializer = new StringSerializer();