diff --git a/remote-api/src/main/java/org/alfresco/rest/api/nodes/NodeFolderSizeRelation.java b/remote-api/src/main/java/org/alfresco/rest/api/nodes/NodeFolderSizeRelation.java
index 4ab8e65fb2..ba4279c5d8 100644
--- a/remote-api/src/main/java/org/alfresco/rest/api/nodes/NodeFolderSizeRelation.java
+++ b/remote-api/src/main/java/org/alfresco/rest/api/nodes/NodeFolderSizeRelation.java
@@ -48,8 +48,8 @@ import org.alfresco.service.cmr.security.AccessStatus;
 import org.alfresco.service.cmr.security.PermissionService;
 import org.alfresco.service.namespace.QName;
 import org.alfresco.util.ParameterCheck;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.extensions.webscripts.Status;
 
@@ -79,7 +79,7 @@ public class NodeFolderSizeRelation implements
     /**
      * The logger
      */
-    private static final Log LOGGER = LogFactory.getLog(NodeFolderSizeRelation.class);
+    private static final Logger LOG = LoggerFactory.getLogger(NodeFolderSizeRelation.class);
 
     /**
      * The class that wraps the ReST APIs from core.
@@ -153,7 +153,7 @@ public class NodeFolderSizeRelation implements
         }
         catch (Exception ex)
         {
-            LOGGER.error("Exception occured in NodeFolderSizeRelation:createById "+ex.getMessage());
+            LOG.error("Exception occured in NodeFolderSizeRelation:createById {}", ex.getMessage());
         }
         return null;
     }
@@ -200,7 +200,7 @@ public class NodeFolderSizeRelation implements
         }
         catch (Exception ex)
         {
-            LOGGER.error("Exception occured in NodeFolderSizeRelation:readById "+ex.getMessage());
+            LOG.error("Exception occured in NodeFolderSizeRelation:readById {}", ex.getMessage());
         }
         return null;
     }
diff --git a/remote-api/src/test/java/org/alfresco/rest/api/tests/NodeFolderSizeApiTest.java b/remote-api/src/test/java/org/alfresco/rest/api/tests/NodeFolderSizeApiTest.java
index 4a59d5e609..e9366f71c7 100644
--- a/remote-api/src/test/java/org/alfresco/rest/api/tests/NodeFolderSizeApiTest.java
+++ b/remote-api/src/test/java/org/alfresco/rest/api/tests/NodeFolderSizeApiTest.java
@@ -33,11 +33,11 @@ import org.alfresco.rest.api.tests.client.HttpResponse;
 import org.alfresco.rest.api.tests.util.RestApiUtil;
 import org.alfresco.service.cmr.security.PermissionService;
 import org.alfresco.service.cmr.site.SiteVisibility;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -45,7 +45,6 @@ import java.util.UUID;
 
 import static org.alfresco.rest.api.tests.util.RestApiUtil.toJsonAsStringNonNull;
 import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
 
 /**
  * V1 REST API tests for Folder size
@@ -61,6 +60,11 @@ public class NodeFolderSizeApiTest extends AbstractBaseApiTest{
 
     protected PermissionService permissionService;
 
+    /**
+     * The logger
+     */
+    private static final Logger LOG = LoggerFactory.getLogger(NodeFolderSizeApiTest.class);
+
     private String addToDocumentLibrary(Site testSite, String name, String nodeType)
     {
         String parentId;
@@ -70,8 +74,9 @@ public class NodeFolderSizeApiTest extends AbstractBaseApiTest{
             return createNode(parentId, name, nodeType, null).getId();
         } catch (Exception e)
         {
-            throw new RuntimeException(e.getMessage());
+            LOG.error("Exception occured in NodeFolderSizeApiTest:addToDocumentLibrary {}", e.getMessage());
         }
+        return null;
     }
 
     @Before
diff --git a/repository/src/main/java/org/alfresco/model/FolderSizeModel.java b/repository/src/main/java/org/alfresco/model/FolderSizeModel.java
index 39e9c554a5..77dd4b0c8d 100644
--- a/repository/src/main/java/org/alfresco/model/FolderSizeModel.java
+++ b/repository/src/main/java/org/alfresco/model/FolderSizeModel.java
@@ -29,11 +29,11 @@ import org.alfresco.api.AlfrescoPublicApi;
 import org.alfresco.service.namespace.QName;
 
 @AlfrescoPublicApi
-public interface FolderSizeModel {
+public class FolderSizeModel {
 
     /** Folder Model URI */
-    String SIZE_MODEL_1_0_URI = "http://www.alfresco.org/model/size/1.0";
+    private static final String SIZE_MODEL_1_0_URI = "http://www.alfresco.org/model/size/1.0";
 
-    QName PROP_STATUS = QName.createQName(SIZE_MODEL_1_0_URI, "status");
-    QName PROP_OUTPUT = QName.createQName(SIZE_MODEL_1_0_URI, "result");
+    public static final QName PROP_STATUS = QName.createQName(SIZE_MODEL_1_0_URI, "status");
+    public static final QName PROP_OUTPUT = QName.createQName(SIZE_MODEL_1_0_URI, "result");
 }
diff --git a/repository/src/main/java/org/alfresco/repo/action/executer/NodeSizeActionExecuter.java b/repository/src/main/java/org/alfresco/repo/action/executer/NodeSizeActionExecuter.java
index ade59d3ef3..ff91cd5a7c 100644
--- a/repository/src/main/java/org/alfresco/repo/action/executer/NodeSizeActionExecuter.java
+++ b/repository/src/main/java/org/alfresco/repo/action/executer/NodeSizeActionExecuter.java
@@ -36,8 +36,8 @@ import org.alfresco.service.cmr.repository.StoreRef;
 import org.alfresco.service.cmr.search.ResultSet;
 import org.alfresco.service.cmr.search.SearchParameters;
 import org.alfresco.service.cmr.search.SearchService;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.Serializable;
 import java.time.Instant;
@@ -65,7 +65,7 @@ public class NodeSizeActionExecuter extends ActionExecuterAbstractBase
     /**
      * The logger
      */
-    private static final Log LOGGER = LogFactory.getLog(NodeSizeActionExecuter.class);
+    private static final Logger LOG = LoggerFactory.getLogger(NodeSizeActionExecuter.class);
 
     /**
      * Set the node service
@@ -150,7 +150,7 @@ public class NodeSizeActionExecuter extends ActionExecuterAbstractBase
         }
         catch (RuntimeException ex)
         {
-            LOGGER.error("Exception occured in NodeSizeActionExecutor:results "+ex.getMessage());
+            LOG.error("Exception occured in NodeSizeActionExecutor:results {}", ex.getMessage());
         }
 
         final LocalDateTime eventTimestamp = LocalDateTime.ofInstant(Instant.now(), ZoneId.systemDefault());