use static logger instance in ExperimentActor too

src/main/java/eu/hbp/mip/akka/ExperimentActor.java

 package eu.hbp.mip.akka;
 
 import akka.actor.UntypedActor;
-import akka.event.Logging;
-import akka.event.LoggingAdapter;
 import eu.hbp.mip.messages.external.QueryError;
 import eu.hbp.mip.messages.external.QueryResult;
 import eu.hbp.mip.model.Experiment;
 import eu.hbp.mip.repositories.ExperimentRepository;
+import org.apache.log4j.Logger;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.context.annotation.Scope;
@@ -26,37 +25,37 @@ public class ExperimentActor extends UntypedActor {
     @Autowired
     private ExperimentRepository experimentRepository;
 
-    private LoggingAdapter log = Logging.getLogger(getContext().system(), this);
+    private static final Logger LOGGER = Logger.getLogger(ExperimentActor.class);
 
 
     @Override
     public void onReceive(Object message) {
-        log.info("ActorExperiment - onReceive method has been called");
+        LOGGER.info("ActorExperiment - onReceive method has been called");
         UUID uuid = UUID.fromString(this.getSelf().path().name());
-        log.info("\n\nExperimentActor received response from woken for UUID: \n"+uuid.toString());
+        LOGGER.info("\n\nExperimentActor received response from woken for UUID: \n"+uuid.toString());
         if (message instanceof QueryResult) {
             QueryResult queryResult = (QueryResult) message;
             Experiment experiment = experimentRepository.findOne(uuid);
             if(experiment == null)
             {
-                log.error("Experiment with UUID="+uuid+" not found in DB");
+                LOGGER.error("Experiment with UUID="+uuid+" not found in DB");
                 getContext().stop(getSelf());
                 return;
             }
             experiment.setResult(queryResult.data().get());
             experiment.setFinished(new Date());
             experimentRepository.save(experiment);
-            log.info("Experiment "+ uuid +" updated (finished)");
+            LOGGER.info("Experiment "+ uuid +" updated (finished)");
             getContext().stop(getSelf());
         }
 
         else if (message instanceof QueryError) {
             QueryError queryError = (QueryError) message;
-            log.warning("received query error");
+            LOGGER.warn("received query error");
             Experiment experiment = experimentRepository.findOne(uuid);
             if(experiment == null)
             {
-                log.error("Experiment with UUID="+uuid+" not found in DB");
+                LOGGER.error("Experiment with UUID="+uuid+" not found in DB");
                 getContext().stop(getSelf());
                 return;
             }
@@ -65,7 +64,7 @@ public class ExperimentActor extends UntypedActor {
             experimentRepository.save(experiment);
             experiment.setFinished(new Date());
             experimentRepository.save(experiment);
-            log.info("Experiment "+ uuid +" updated (finished)");
+            LOGGER.info("Experiment "+ uuid +" updated (finished)");
             getContext().stop(getSelf());
         }