diff --git a/core/platform-api/che-core-api-project/src/main/java/org/eclipse/che/api/project/server/AttributeFilter.java b/core/platform-api/che-core-api-project/src/main/java/org/eclipse/che/api/project/server/AttributeFilter.java
index 037df452cf..d968575eb9 100644
--- a/core/platform-api/che-core-api-project/src/main/java/org/eclipse/che/api/project/server/AttributeFilter.java
+++ b/core/platform-api/che-core-api-project/src/main/java/org/eclipse/che/api/project/server/AttributeFilter.java
@@ -181,7 +181,7 @@ public class AttributeFilter {
             if (factory == null) {
                 List<String> value = projectConfig.getAttributes().get(attribute.getName());
 
-                persistentAttributes.put(variable.getName(), MoreObjects.firstNonNull(value, new ArrayList<>()));
+                persistentAttributes.put(variable.getName(), MoreObjects.firstNonNull(value, new ArrayList<String>()));
             }
         }