diff --git a/src/main/java/org/gcube/data/access/storagehub/handlers/plugins/FolderPluginHandler.java b/src/main/java/org/gcube/data/access/storagehub/handlers/plugins/FolderPluginHandler.java
index fc517f0..e739600 100644
--- a/src/main/java/org/gcube/data/access/storagehub/handlers/plugins/FolderPluginHandler.java
+++ b/src/main/java/org/gcube/data/access/storagehub/handlers/plugins/FolderPluginHandler.java
@@ -2,9 +2,7 @@ package org.gcube.data.access.storagehub.handlers.plugins;
 
 import java.util.Collections;
 import java.util.Map;
-import java.util.stream.Collectors;
 
-import javax.enterprise.inject.Default;
 import javax.enterprise.inject.Instance;
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -20,6 +18,7 @@ import org.gcube.common.storagehub.model.items.ExternalFolder;
 import org.gcube.common.storagehub.model.items.Item;
 import org.gcube.common.storagehub.model.plugins.FolderManager;
 import org.gcube.common.storagehub.model.plugins.FolderManagerConnector;
+import org.gcube.common.storagehub.model.storages.StorageBackend;
 import org.gcube.data.access.storagehub.handlers.items.Node2ItemConverter;
 import org.gcube.data.access.storagehub.storage.backend.impl.GcubeFolderManager;
 import org.slf4j.Logger;
@@ -27,37 +26,44 @@ import org.slf4j.LoggerFactory;
 
 @Singleton
 public class FolderPluginHandler {
-	
+
 	private static Logger log = LoggerFactory.getLogger(FolderPluginHandler.class);
-	
+
 	@Inject
 	Node2ItemConverter node2Item;
-	
+
 	private GcubeFolderManager defaultManager = new GcubeFolderManager();
-	
+
 	public FolderManager getDefault() {
 		return defaultManager;
 	}
-	
+
 	@Inject
 	Instance<FolderManagerConnector> connectors;
-	
+
 	private Map<String, FolderManagerConnector> connectorsMap;
-	
+
+	private Map<String, StorageBackend> storagesMap;
+
 	FolderPluginHandler(){
-		if (connectors !=null)
-			connectorsMap = connectors.stream().collect(Collectors.toMap(FolderManagerConnector::getName, e -> e ));
+		if (connectors !=null) 
+			for (FolderManagerConnector connector : connectors) {
+				if (connectorsMap.containsKey(connector.getName()))
+						throw new RuntimeException("multiple connectors with the same name found");
+				connectorsMap.put(connector.getName(), connector);
+				
+			}
 		else {
 			log.info("connectors are null");
 			connectorsMap = Collections.emptyMap();
 		}
 	}
-	
+
 	public FolderManagerConnector getConnector(String name) throws PluginNotFoundException  {
 		if (!connectorsMap.containsKey(name)) throw new PluginNotFoundException("plugin "+name+" not found");
 		return connectorsMap.get(name);
 	}
-	
+
 	public FolderManager getFolderManager(Item item) throws PluginInitializationException, PluginNotFoundException, RepositoryException, BackendGenericError{
 		if (!item.isExternalManaged())
 			return defaultManager;
@@ -67,7 +73,7 @@ public class FolderPluginHandler {
 			String parentId = item.getParentId();
 			Node node = session.getNodeByIdentifier(parentId);
 			parent = node2Item.getItem(node, Excludes.ALL);
-			
+
 			if (parent !=null && parent instanceof ExternalFolder) {
 				ExternalFolder extParent = (ExternalFolder) parent;
 				String plugin = extParent.getManagedBy();