diff --git a/catalogue/build.gradle b/catalogue/build.gradle
index ed8df0f1e..efd4df84f 100644
--- a/catalogue/build.gradle
+++ b/catalogue/build.gradle
@@ -30,6 +30,7 @@ apply from: '../gradle/gradle/nexus.upload.plugin.gradle'
 dependencies {
     compile 'org.springframework.boot:spring-boot-starter-security:'+ springBootVersion
     compile group: 'org.hibernate.javax.persistence', name: 'hibernate-jpa-2.1-api', version: '1.0.2.Final'
+    compile group: 'org.hibernate', name: 'hibernate-core', version: '5.0.12.Final'
 
     compile 'com.fasterxml.jackson.core:jackson-annotations:2.8.6'
     compile 'org.hibernate:hibernate-validator:5.3.5.Final'
diff --git a/catalogue/src/main/java/org/openbaton/catalogue/mano/descriptor/VirtualDeploymentUnit.java b/catalogue/src/main/java/org/openbaton/catalogue/mano/descriptor/VirtualDeploymentUnit.java
index 4ea898163..f8c3c455c 100644
--- a/catalogue/src/main/java/org/openbaton/catalogue/mano/descriptor/VirtualDeploymentUnit.java
+++ b/catalogue/src/main/java/org/openbaton/catalogue/mano/descriptor/VirtualDeploymentUnit.java
@@ -16,6 +16,7 @@
 
 package org.openbaton.catalogue.mano.descriptor;
 
+import java.util.List;
 import java.util.Set;
 import javax.persistence.CascadeType;
 import javax.persistence.ElementCollection;
@@ -24,6 +25,8 @@
 import javax.persistence.OneToMany;
 import javax.persistence.OneToOne;
 import javax.validation.constraints.Min;
+import org.hibernate.annotations.Fetch;
+import org.hibernate.annotations.FetchMode;
 import org.openbaton.catalogue.mano.common.HighAvailability;
 import org.openbaton.catalogue.mano.common.LifecycleEvent;
 import org.openbaton.catalogue.mano.common.faultmanagement.FaultManagementPolicy;
@@ -46,7 +49,8 @@ public class VirtualDeploymentUnit extends BaseEntity {
    * virtualisation containers as per (ETSI GS NFV-SWA 001 [i.8]).
    */
   @ElementCollection(fetch = FetchType.EAGER)
-  private Set<String> vm_image;
+  @Fetch(FetchMode.SELECT)
+  private List<String> vm_image;
   /** Reference to the VDU (vnfd:vdu:id) used to instantiate this element. */
   private String parent_vdu;
   /**
@@ -126,11 +130,11 @@ public void setVnfc_instance(Set<VNFCInstance> vnfc_instance) {
     this.vnfc_instance = vnfc_instance;
   }
 
-  public Set<String> getVm_image() {
+  public List<String> getVm_image() {
     return vm_image;
   }
 
-  public void setVm_image(Set<String> vm_image) {
+  public void setVm_image(List<String> vm_image) {
     this.vm_image = vm_image;
   }
 
diff --git a/core/core-impl/src/main/java/org/openbaton/nfvo/core/api/VNFPackageManagement.java b/core/core-impl/src/main/java/org/openbaton/nfvo/core/api/VNFPackageManagement.java
index d84a85430..8171d12be 100644
--- a/core/core-impl/src/main/java/org/openbaton/nfvo/core/api/VNFPackageManagement.java
+++ b/core/core-impl/src/main/java/org/openbaton/nfvo/core/api/VNFPackageManagement.java
@@ -610,7 +610,7 @@ public BaseNfvImage handleImage(
               image = vim.add(vimInstance, image, imageFile);
             }
             if (vdu.getVm_image() == null) {
-              vdu.setVm_image(new LinkedHashSet<>());
+              vdu.setVm_image(new ArrayList<>());
             }
             vdu.getVm_image().add(image.getExtId());
             vimInstance = vimManagement.refresh(vimInstance, true).get();
@@ -629,7 +629,7 @@ public BaseNfvImage handleImage(
           .forEach(
               virtualDeploymentUnit -> {
                 if (virtualDeploymentUnit.getVm_image() == null) {
-                  virtualDeploymentUnit.setVm_image(new LinkedHashSet<>());
+                  virtualDeploymentUnit.setVm_image(new ArrayList<>());
                 }
                 if (ids != null) virtualDeploymentUnit.getVm_image().addAll(ids);
                 if (names != null) virtualDeploymentUnit.getVm_image().addAll(names);
diff --git a/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/NetworkServiceRecordManagementClassSuiteTest.java b/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/NetworkServiceRecordManagementClassSuiteTest.java
index eebe7b66d..4600e8549 100644
--- a/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/NetworkServiceRecordManagementClassSuiteTest.java
+++ b/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/NetworkServiceRecordManagementClassSuiteTest.java
@@ -494,7 +494,7 @@ private VirtualNetworkFunctionDescriptor createVirtualNetworkFunctionDescriptor(
           {
             VirtualDeploymentUnit vdu = new VirtualDeploymentUnit();
             vdu.setVm_image(
-                new LinkedHashSet<String>() {
+                new ArrayList<String>() {
                   {
                     add("mocked_image");
                   }
@@ -560,7 +560,7 @@ private NetworkServiceRecord createNetworkServiceRecord() {
             highAvailability.setResiliencyLevel(ResiliencyLevel.ACTIVE_STANDBY_STATELESS);
             vdu.setHigh_availability(highAvailability);
             vdu.setVm_image(
-                new LinkedHashSet<String>() {
+                new ArrayList<String>() {
                   {
                     add("mocked_image");
                   }
diff --git a/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/VNFLifecycleOperationGrantingClassSuiteTest.java b/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/VNFLifecycleOperationGrantingClassSuiteTest.java
index 77e57c7ce..2b33eb568 100644
--- a/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/VNFLifecycleOperationGrantingClassSuiteTest.java
+++ b/core/core-impl/src/test/java/org/openbaton/nfvo/core/test/VNFLifecycleOperationGrantingClassSuiteTest.java
@@ -23,6 +23,7 @@
 import static org.openbaton.nfvo.core.test.TestUtils.createMinQuota;
 import static org.openbaton.nfvo.core.test.TestUtils.createVimInstance;
 
+import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -126,7 +127,7 @@ private VirtualDeploymentUnit createVDU(int suffix, BaseVimInstance vimInstance)
     highAvailability.setResiliencyLevel(ResiliencyLevel.ACTIVE_STANDBY_STATELESS);
     vdu.setHigh_availability(highAvailability);
     vdu.setVm_image(
-        new HashSet<String>() {
+        new ArrayList<String>() {
           {
             add("mocked_image");
           }
diff --git a/tosca-parser/src/main/java/org/openbaton/tosca/templates/TopologyTemplate/Nodes/VDU/VDUNodeTemplate.java b/tosca-parser/src/main/java/org/openbaton/tosca/templates/TopologyTemplate/Nodes/VDU/VDUNodeTemplate.java
index cad46e482..ba7f3e346 100755
--- a/tosca-parser/src/main/java/org/openbaton/tosca/templates/TopologyTemplate/Nodes/VDU/VDUNodeTemplate.java
+++ b/tosca-parser/src/main/java/org/openbaton/tosca/templates/TopologyTemplate/Nodes/VDU/VDUNodeTemplate.java
@@ -16,9 +16,9 @@
 
 package org.openbaton.tosca.templates.TopologyTemplate.Nodes.VDU;
 
-import java.util.LinkedHashSet;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import org.openbaton.tosca.templates.TopologyTemplate.Nodes.NodeTemplate;
 
 @SuppressWarnings({"unsafe", "unchecked"})
@@ -26,7 +26,7 @@ public class VDUNodeTemplate {
 
   private String type;
   private String name;
-  private Set<String> artifacts = new LinkedHashSet<>();
+  private List<String> artifacts = new ArrayList<>();
   private VDUProperties properties;
 
   public VDUNodeTemplate(NodeTemplate nodeTemplate, String name) {
@@ -61,11 +61,11 @@ public void setType(String type) {
     this.type = type;
   }
 
-  public Set<String> getArtifacts() {
+  public List<String> getArtifacts() {
     return artifacts;
   }
 
-  public void setArtifacts(LinkedHashSet<String> vduArtifact) {
+  public void setArtifacts(ArrayList<String> vduArtifact) {
     this.artifacts = vduArtifact;
   }
 
diff --git a/vim-impl/src/test/java/org/openbaton/vim_impl/vim/test/VimTestSuiteClass.java b/vim-impl/src/test/java/org/openbaton/vim_impl/vim/test/VimTestSuiteClass.java
index 8ed5ba703..a809f2775 100644
--- a/vim-impl/src/test/java/org/openbaton/vim_impl/vim/test/VimTestSuiteClass.java
+++ b/vim-impl/src/test/java/org/openbaton/vim_impl/vim/test/VimTestSuiteClass.java
@@ -23,9 +23,10 @@
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Mockito.when;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
@@ -224,7 +225,7 @@ private VirtualDeploymentUnit createVDU() {
     monitoring_parameter.add("parameter_3");
     vdu.setMonitoring_parameter(monitoring_parameter);
     vdu.setComputation_requirement("m1.small");
-    Set<String> vm_images = new LinkedHashSet<>();
+    List<String> vm_images = new ArrayList<>();
     vm_images.add("image_1234");
     vdu.setVm_image(vm_images);
     vimInstance.setFlavours(new HashSet<>());