diff --git a/src/main/java/org/onap/aai/babel/csar/CsarToXmlConverter.java b/src/main/java/org/onap/aai/babel/csar/CsarToXmlConverter.java
index 9e1ff6e..6115f8f 100644
--- a/src/main/java/org/onap/aai/babel/csar/CsarToXmlConverter.java
+++ b/src/main/java/org/onap/aai/babel/csar/CsarToXmlConverter.java
@@ -75,7 +75,7 @@
             logger.debug(xmlArtifacts.size() + " XML artifact(s) have been generated");
         } catch (InvalidArchiveException e) {
             throw new CsarConverterException(
-                    "An error occurred trying to extract the YMAL files from the csar file : " + e);
+                    "An error occurred trying to extract the YAML files from the CSAR file : " + e);
         } catch (XmlArtifactGenerationException e) {
             throw new CsarConverterException(
                     "An error occurred trying to generate XML files from a collection of YAML files : " + e);
diff --git a/src/main/java/org/onap/aai/babel/csar/extractor/YamlExtractor.java b/src/main/java/org/onap/aai/babel/csar/extractor/YamlExtractor.java
index 15d77a1..424e661 100644
--- a/src/main/java/org/onap/aai/babel/csar/extractor/YamlExtractor.java
+++ b/src/main/java/org/onap/aai/babel/csar/extractor/YamlExtractor.java
@@ -75,11 +75,11 @@
                 }
             }
             if (ymlFiles.isEmpty()) {
-                throw new InvalidArchiveException("No valid YAML files were found in the csar file.");
+                throw new InvalidArchiveException("No valid YAML files were found in the CSAR file.");
             }
         } catch (IOException e) {
             throw new InvalidArchiveException(
-                    "An error occurred trying to create a ZipFile. Is the content being converted really a csar file?",
+                    "An error occurred trying to create a ZipFile. Is the content being converted really a CSAR file?",
                     e);
         }
 
@@ -90,7 +90,7 @@
 
     /**
      * Throw an error if the supplied parameters are not valid.
-     * 
+     *
      * @param archive
      * @param name
      * @param version
diff --git a/src/main/java/org/onap/aai/babel/parser/ArtifactGeneratorToscaParser.java b/src/main/java/org/onap/aai/babel/parser/ArtifactGeneratorToscaParser.java
index 0777e51..2816cb5 100644
--- a/src/main/java/org/onap/aai/babel/parser/ArtifactGeneratorToscaParser.java
+++ b/src/main/java/org/onap/aai/babel/parser/ArtifactGeneratorToscaParser.java
@@ -351,10 +351,13 @@
      */
     private void processVfModule(List<Resource> resources, Model vfModel, Group groupDefinition,
             NodeTemplate serviceNode, Resource groupModel) throws XmlArtifactGenerationException {
-        groupModel.populateModelIdentificationInformation(
-                mergeProperties(groupDefinition.getMetadata().getAllProperties(), groupDefinition.getProperties()));
+        Metadata metadata = groupDefinition.getMetadata();
 
+        Map<String, String> mergedProperties =
+                mergeProperties(metadata == null ? Collections.emptyMap() : metadata.getAllProperties(),
+                        groupDefinition.getProperties());
 
+        groupModel.populateModelIdentificationInformation(mergedProperties);
         SubstitutionMappings substitutionMappings = serviceNode.getSubMappingToscaTemplate();
         if (substitutionMappings != null) {
             processVfModuleGroup(groupModel, getVfModuleMembers(substitutionMappings,
@@ -457,29 +460,34 @@
      *            parent Resource
      * @param metaData
      *            for populating the Resource IDs
-     * @param resourceNode
-     *            any Model (will be ignored if not a Resource)
+     * @param childResource
+     *            a child Resource (will be ignored if this is a Widget type)
      * @param nodeProperties
      *            the node properties
      * @return whether or not a ProvidingService was processed
      */
-    private boolean processModel(Model resourceModel, Metadata metaData, Resource resourceNode,
+    private boolean processModel(Model resourceModel, Metadata metaData, Resource childResource,
             Map<String, Property> nodeProperties) {
-        boolean foundProvidingService = resourceNode != null
-                && (boolean) Optional.ofNullable(resourceNode.getProperties().get("providingService")).orElse(false);
+        boolean isProvidingService = childResource != null
+                && (boolean) Optional.ofNullable(childResource.getProperties().get("providingService")).orElse(false);
 
-        if (foundProvidingService) {
-            processProvidingService(resourceModel, resourceNode, nodeProperties);
-        } else if (resourceNode != null && resourceNode.getModelType() == ModelType.RESOURCE
-                && !resourceNode.hasWidgetType("L3_NET")) {
+        if (isProvidingService) {
+            processProvidingService(resourceModel, childResource, nodeProperties);
+        } else if (childResource != null && childResource.getModelType() == ModelType.RESOURCE
+                && !childResource.hasWidgetType("L3_NET")) {
             if (metaData != null) {
-                resourceNode.populateModelIdentificationInformation(metaData.getAllProperties());
+                childResource.populateModelIdentificationInformation(metaData.getAllProperties());
             }
-            resourceModel.addResource(resourceNode);
+            resourceModel.addResource(childResource);
         }
-        return foundProvidingService;
+        return isProvidingService;
     }
 
+    /**
+     * @param resourceModel
+     * @param resourceNode
+     * @param nodeProperties
+     */
     private void processProvidingService(Model resourceModel, Resource resourceNode,
             Map<String, Property> nodeProperties) {
         if (nodeProperties == null || nodeProperties.get("providing_service_uuid") == null
diff --git a/src/main/java/org/onap/aai/babel/xml/generator/api/AaiArtifactGenerator.java b/src/main/java/org/onap/aai/babel/xml/generator/api/AaiArtifactGenerator.java
index 32237b5..424b1a6 100644
--- a/src/main/java/org/onap/aai/babel/xml/generator/api/AaiArtifactGenerator.java
+++ b/src/main/java/org/onap/aai/babel/xml/generator/api/AaiArtifactGenerator.java
@@ -105,7 +105,7 @@
             ISdcCsarHelper csarHelper =
                     SdcToscaParserFactory.getInstance().getSdcCsarHelper(csarPath.toAbsolutePath().toString());
             return generateAllArtifacts(validateServiceVersion(additionalParams), csarHelper);
-        } catch (SdcToscaParserException | XmlArtifactGenerationException e) {
+        } catch (SdcToscaParserException | ClassCastException | XmlArtifactGenerationException e) {
             log.error(ApplicationMsgs.INVALID_CSAR_FILE, e);
             return createErrorData(e);
         } finally {
@@ -131,17 +131,11 @@
      */
     public GenerationData generateAllArtifacts(final String serviceVersion, ISdcCsarHelper csarHelper)
             throws XmlArtifactGenerationException {
-        List<NodeTemplate> serviceNodeTemplates =
-                ToscaParser.getServiceNodeTemplates(csarHelper).collect(Collectors.toList());
-        if (serviceNodeTemplates == null) {
-            throw new IllegalArgumentException(GENERATOR_AAI_ERROR_MISSING_SERVICE_TOSCA);
-        }
-
         Service serviceModel = createServiceModel(serviceVersion, csarHelper.getServiceMetadataAllProperties());
 
         MDC.put(MDC_PARAM_MODEL_INFO, serviceModel.getModelName() + "," + getArtifactLabel(serviceModel));
 
-        List<Resource> resources = generateResourceModels(csarHelper, serviceNodeTemplates, serviceModel);
+        List<Resource> resources = generateResourceModels(csarHelper, serviceModel);
 
         // Generate the A&AI XML model for the Service.
         final String serviceArtifact = modelGenerator.generateModelFor(serviceModel);
@@ -183,18 +177,21 @@
 
     /**
      * @param csarHelper
-     * @param serviceNodeTemplates
      * @param serviceModel
      * @return the generated Models
      * @throws XmlArtifactGenerationException
      *             if the configured widget mappings do not support processed widget type(s)
      */
-    private List<Resource> generateResourceModels(ISdcCsarHelper csarHelper, List<NodeTemplate> serviceNodeTemplates,
-            Service serviceModel) throws XmlArtifactGenerationException {
+    private List<Resource> generateResourceModels(ISdcCsarHelper csarHelper, Service serviceModel)
+            throws XmlArtifactGenerationException {
+        List<NodeTemplate> serviceNodeTemplates =
+                ToscaParser.getServiceNodeTemplates(csarHelper).collect(Collectors.toList());
+        if (serviceNodeTemplates == null) {
+            throw new IllegalArgumentException(GENERATOR_AAI_ERROR_MISSING_SERVICE_TOSCA);
+        }
+
         final ArtifactGeneratorToscaParser parser = new ArtifactGeneratorToscaParser(csarHelper);
-
         List<Resource> resources = new ArrayList<>();
-
         final List<Group> serviceGroups = ToscaParser.getServiceLevelGroups(csarHelper);
         for (NodeTemplate nodeTemplate : serviceNodeTemplates) {
             if (nodeTemplate.getMetaData() != null) {
@@ -436,15 +433,17 @@
 
     private int hashCodeUuId(String uuId) {
         int hashcode = 0;
-        for (int i = 0; i < uuId.length(); i++) {
-            hashcode = 31 * hashcode + uuId.charAt(i);
+        if (uuId != null) {
+            for (int i = 0; i < uuId.length(); i++) {
+                hashcode = 31 * hashcode + uuId.charAt(i);
+            }
         }
         return hashcode;
     }
 
     private String truncateName(String name) {
         String truncatedName = name;
-        if (name.length() >= 200) {
+        if (name != null && name.length() >= 200) {
             truncatedName = name.substring(0, 199);
         }
         return truncatedName;
diff --git a/src/main/java/org/onap/aai/babel/xml/generator/model/Resource.java b/src/main/java/org/onap/aai/babel/xml/generator/model/Resource.java
index 04c69bb..8c01a50 100644
--- a/src/main/java/org/onap/aai/babel/xml/generator/model/Resource.java
+++ b/src/main/java/org/onap/aai/babel/xml/generator/model/Resource.java
@@ -21,9 +21,12 @@
 
 package org.onap.aai.babel.xml.generator.model;
 
+import com.google.common.collect.ImmutableMap;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
 import org.onap.aai.babel.xml.generator.XmlArtifactGenerationException;
 import org.onap.aai.babel.xml.generator.types.ModelType;
 
@@ -135,9 +138,19 @@
 
     @Override
     public String toString() {
-        return "Resource [widget type=" + getWidgetType() + ", deleteFlag=" + deleteFlag + ", modelType=" + modelType
-                + ", properties=" + properties + ", vserver=" + vserver + ", addlintf=" + addlintf + ", addvolume="
-                + addvolume + ", members=" + members + "]";
+        return ImmutableMap.<String, String>builder() //
+                .put("Resource", Optional.ofNullable(getModelId()).orElse("null")) //
+                .put("widget type", getWidgetType().toString()) //
+                .put("deleteFlag", Boolean.toString(deleteFlag)) //
+                .put("modelType", modelType.toString()) //
+                .put("properties", properties.toString()) //
+                .put("vserver", Optional.ofNullable(vserver).map(Widget::toString).orElse("null")) //
+                .put("addlintf", Boolean.toString(addlintf)) //
+                .put("addvolume", Boolean.toString(addvolume)) //
+                .put("members", Optional.ofNullable(members).map(List::toString).orElse("null")) //
+                .build().entrySet().stream() //
+                .map(e -> e.getKey() + "=" + e.getValue()) //
+                .collect(Collectors.joining(", "));
     }
 
     private void addVolumeWidget(Widget widget) {
diff --git a/src/test/java/org/onap/aai/babel/csar/extractor/YamlExtractorTest.java b/src/test/java/org/onap/aai/babel/csar/extractor/YamlExtractorTest.java
index 5bb7763..20c3434 100644
--- a/src/test/java/org/onap/aai/babel/csar/extractor/YamlExtractorTest.java
+++ b/src/test/java/org/onap/aai/babel/csar/extractor/YamlExtractorTest.java
@@ -2,8 +2,8 @@
  * ============LICENSE_START=======================================================
  * org.onap.aai
  * ================================================================================
- * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
- * Copyright © 2017-2018 European Software Marketing Ltd.
+ * Copyright © 2017-2019 AT&T Intellectual Property. All rights reserved.
+ * Copyright © 2017-2019 European Software Marketing Ltd.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -91,7 +91,7 @@
     @Test
     public void testInvalidContentSupplied() {
         invalidArgumentsTest("This is a piece of nonsense and not a zip file".getBytes(), FOO, FOO,
-                "An error occurred trying to create a ZipFile. Is the content being converted really a csar file?");
+                "An error occurred trying to create a ZipFile. Is the content being converted really a CSAR file?");
     }
 
     @Test
@@ -102,7 +102,7 @@
         } catch (Exception e) {
             assertTrue("An instance of InvalidArchiveException should have been thrown.",
                     e instanceof InvalidArchiveException);
-            assertEquals("Incorrect message was returned", "No valid YAML files were found in the csar file.",
+            assertEquals("Incorrect message was returned", "No valid YAML files were found in the CSAR file.",
                     e.getMessage());
         }
     }
diff --git a/src/test/java/org/onap/aai/babel/service/TestGenerateArtifactsServiceImpl.java b/src/test/java/org/onap/aai/babel/service/TestGenerateArtifactsServiceImpl.java
index 0673d04..55311a6 100644
--- a/src/test/java/org/onap/aai/babel/service/TestGenerateArtifactsServiceImpl.java
+++ b/src/test/java/org/onap/aai/babel/service/TestGenerateArtifactsServiceImpl.java
@@ -152,8 +152,7 @@
      *             if the resource cannot be loaded
      */
     private Response processJsonRequest(CsarTest csar) throws IOException, URISyntaxException {
-        String jsonString = csar.getJsonRequest();
-        return invokeService(jsonString);
+        return invokeService(csar.getJsonRequest());
     }
 
     /**
diff --git a/src/test/java/org/onap/aai/babel/util/ArtifactTestUtils.java b/src/test/java/org/onap/aai/babel/util/ArtifactTestUtils.java
index 066911e..a98b7c2 100644
--- a/src/test/java/org/onap/aai/babel/util/ArtifactTestUtils.java
+++ b/src/test/java/org/onap/aai/babel/util/ArtifactTestUtils.java
@@ -65,7 +65,7 @@
 
     /**
      * Load the Widget type mappings (resource).
-     *
+     * 
      * @throws IOException
      *             if the configuration file is not loaded
      */
@@ -127,7 +127,11 @@
     }
 
     public String loadResourceAsString(String resourceName) throws IOException {
+        try {
         return IOUtils.toString(getResource(resourceName), Charset.defaultCharset());
+        } catch (NullPointerException e) {
+            throw new IllegalArgumentException("No such resource " + resourceName);
+        }
     }
 
     public String getRequestJson(String resource) throws IOException {
@@ -144,7 +148,7 @@
 
     /**
      * Create Properties from the content of the named resource (e.g. a file on the classpath).
-     *
+     * 
      * @param resourceName
      *            the resource name
      * @return Properties loaded from the named resource