diff --git a/pom.xml b/pom.xml
index 5e596a7..d49d47f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -162,7 +162,7 @@
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
 				<configuration>
-					<source>1.7</source>
+					<source>${maven.compiler.source}</source>
 					<target>${maven.compiler.target}</target>
 				</configuration>
 			</plugin>
diff --git a/src/main/java/org/gcube/portlets/user/rstudio_wrapper_portlet/server/RStudioServiceImpl.java b/src/main/java/org/gcube/portlets/user/rstudio_wrapper_portlet/server/RStudioServiceImpl.java
index 6fa20bc..ccb1675 100644
--- a/src/main/java/org/gcube/portlets/user/rstudio_wrapper_portlet/server/RStudioServiceImpl.java
+++ b/src/main/java/org/gcube/portlets/user/rstudio_wrapper_portlet/server/RStudioServiceImpl.java
@@ -1,11 +1,9 @@
 package org.gcube.portlets.user.rstudio_wrapper_portlet.server;
 
-import static org.gcube.data.analysis.rconnector.client.Constants.rConnector;
 import static org.gcube.resources.discovery.icclient.ICFactory.clientFor;
 import static org.gcube.resources.discovery.icclient.ICFactory.queryFor;
 
 import java.net.MalformedURLException;
-import java.net.URI;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
@@ -15,7 +13,6 @@ import org.gcube.common.portal.PortalContext;
 import org.gcube.common.resources.gcore.GCoreEndpoint;
 import org.gcube.common.resources.gcore.GCoreEndpoint.Profile.Endpoint;
 import org.gcube.common.resources.gcore.ServiceEndpoint;
-import org.gcube.common.resources.gcore.utils.Group;
 import org.gcube.common.scope.api.ScopeProvider;
 import org.gcube.portlets.user.rstudio_wrapper_portlet.client.RStudioService;
 import org.gcube.portlets.user.rstudio_wrapper_portlet.shared.RStudioInstance;
@@ -26,10 +23,10 @@ import org.gcube.vomanagement.usermanagement.exception.UserManagementSystemExcep
 import org.gcube.vomanagement.usermanagement.exception.UserRetrievalFault;
 import org.gcube.vomanagement.usermanagement.impl.LiferayUserManager;
 import org.gcube.vomanagement.usermanagement.model.GCubeUser;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import com.google.gwt.user.server.rpc.RemoteServiceServlet;
+import com.liferay.portal.kernel.log.Log;
+import com.liferay.portal.kernel.log.LogFactoryUtil;
 
 /**
  * The server side implementation of the RPC service.
@@ -37,7 +34,8 @@ import com.google.gwt.user.server.rpc.RemoteServiceServlet;
 @SuppressWarnings("serial")
 public class RStudioServiceImpl extends RemoteServiceServlet implements RStudioService {
 
-	private static final Logger _log = LoggerFactory.getLogger(RStudioServiceImpl.class);
+
+	private static Log _log = LogFactoryUtil.getLog(RStudioServiceImpl.class);
 
 	private static final String RSTUDIO_INSTANCES = "RStudio-Instances";
 	private static final String RSTUDIO_URL = "RStudio-URL";
@@ -99,8 +97,7 @@ public class RStudioServiceImpl extends RemoteServiceServlet implements RStudioS
 				}
 
 				hostedOnSet = getUserRStudioInstances(um,curUser).get(scope);
-
-				_log.info("**** Checking if still exist on this scope: " + scope);
+				_log.debug("**** Checking if still exist on this scope: " + scope);
 				//if the instance exists and is still available in the given context
 				if (hostedOnSet != null && checkRStudioInstanceExistence(curUser, hostedOnSet, resources) ) {
 					toReturn = getRConnectorURL(hostedOnSet, token);
@@ -124,19 +121,19 @@ public class RStudioServiceImpl extends RemoteServiceServlet implements RStudioS
 							}
 						}
 					}
-					_log.info("VRE - RStudio allocaiton map as follows: ");
+					_log.debug("VRE - RStudio allocaiton map as follows: ");
 					int min = 0;
 					int i = 0;
 					String host2Select = "";
 					for (String host : rStudioDistributionMap.keySet()) {
-						_log.info("Host " + host + " has # users=" + rStudioDistributionMap.get(host));
+						_log.debug("Host " + host + " has # users=" + rStudioDistributionMap.get(host));
 						if (i==0) {
 							host2Select =  host;
 							min = rStudioDistributionMap.get(host);
 						} else {
 							int usersNo = rStudioDistributionMap.get(host);
 							if (usersNo < min) {
-								_log.info("Host " + host + " has LESS users than " + host2Select + " updating");
+								_log.debug("Host " + host + " has LESS users than " + host2Select + " updating");
 								host2Select = host;
 							}
 						}
@@ -211,19 +208,19 @@ public class RStudioServiceImpl extends RemoteServiceServlet implements RStudioS
 						}
 					}
 				}
-				_log.info("VRE - RStudio allocaiton map as follows: ");
+				_log.debug("VRE - RStudio allocaiton map as follows: ");
 				int min = 0;
 				int i = 0;
 				String host2Select = "";
 				for (String host : rStudioDistributionMap.keySet()) {
-					_log.info("Host " + host + " has # users=" + rStudioDistributionMap.get(host));
+					_log.debug("Host " + host + " has # users=" + rStudioDistributionMap.get(host));
 					if (i==0) {
 						host2Select =  host;
 						min = rStudioDistributionMap.get(host);
 					} else {
 						int usersNo = rStudioDistributionMap.get(host);
 						if (usersNo < min) {
-							_log.info("Host " + host + " has LESS users than " + host2Select + " updating");
+							_log.debug("Host " + host + " has LESS users than " + host2Select + " updating");
 							host2Select = host;
 						}
 					}