diff --git a/ccm-core/src/main/java/org/libreccm/categorization/Domain.java b/ccm-core/src/main/java/org/libreccm/categorization/Domain.java
index cdb1dec7f..ad9704356 100644
--- a/ccm-core/src/main/java/org/libreccm/categorization/Domain.java
+++ b/ccm-core/src/main/java/org/libreccm/categorization/Domain.java
@@ -30,6 +30,7 @@ import org.libreccm.portation.Portable;
 import org.libreccm.security.RecursivePermissions;
 import org.libreccm.web.CcmApplication;
 
+import javax.persistence.FetchType;
 import javax.validation.constraints.Pattern;
 import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlElementWrapper;
@@ -210,7 +211,7 @@ public class Domain extends CcmObject implements Serializable, Portable {
     /**
      * The owners of the domain.
      */
-    @OneToMany(mappedBy = "domain")
+    @OneToMany(mappedBy = "domain", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "owners", namespace = CAT_XML_NS)
     @JsonIgnore
     private List<DomainOwnership> owners;
diff --git a/ccm-core/src/main/java/org/libreccm/core/CcmObject.java b/ccm-core/src/main/java/org/libreccm/core/CcmObject.java
index a45301dd1..4a6e337ca 100644
--- a/ccm-core/src/main/java/org/libreccm/core/CcmObject.java
+++ b/ccm-core/src/main/java/org/libreccm/core/CcmObject.java
@@ -112,7 +112,7 @@ public class CcmObject implements Identifiable, Serializable {
     /**
      * Permissions granted on this object.
      */
-    @OneToMany(mappedBy = "object")
+    @OneToMany(mappedBy = "object", fetch = FetchType.LAZY)
     @IndexedEmbedded(includePaths = {"grantedPrivilege", "grantee.name"})
     @XmlElementWrapper(name = "permissions", namespace = CORE_XML_NS)
     @XmlElement(name = "permission", namespace = CORE_XML_NS)
@@ -122,7 +122,7 @@ public class CcmObject implements Identifiable, Serializable {
     /**
      * Categories which have been assigned to this {@code CcmObject}.
      */
-    @OneToMany(mappedBy = "categorizedObject")
+    @OneToMany(mappedBy = "categorizedObject", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "categories", namespace = CORE_XML_NS)
     @XmlElement(name = "category", namespace = CORE_XML_NS)
     @JsonIgnore
diff --git a/ccm-core/src/main/java/org/libreccm/core/Resource.java b/ccm-core/src/main/java/org/libreccm/core/Resource.java
index c2e0f614c..ec2577767 100644
--- a/ccm-core/src/main/java/org/libreccm/core/Resource.java
+++ b/ccm-core/src/main/java/org/libreccm/core/Resource.java
@@ -39,6 +39,7 @@ import javax.persistence.AssociationOverride;
 import javax.persistence.Column;
 import javax.persistence.Embedded;
 import javax.persistence.Entity;
+import javax.persistence.FetchType;
 import javax.persistence.JoinColumn;
 import javax.persistence.JoinTable;
 import javax.persistence.ManyToOne;
@@ -114,7 +115,7 @@ public class Resource extends CcmObject implements Serializable {
     /**
      * The child resources of this resource.
      */
-    @OneToMany(mappedBy = "parent")
+    @OneToMany(mappedBy = "parent", fetch = FetchType.LAZY)
     @JsonIgnore
     private List<Resource> childs;
 
diff --git a/ccm-core/src/main/java/org/libreccm/l10n/LocalizedString.java b/ccm-core/src/main/java/org/libreccm/l10n/LocalizedString.java
index 53455b78b..996745aaa 100644
--- a/ccm-core/src/main/java/org/libreccm/l10n/LocalizedString.java
+++ b/ccm-core/src/main/java/org/libreccm/l10n/LocalizedString.java
@@ -73,7 +73,6 @@ public class LocalizedString implements Serializable {
     @Lob
     @Type(type = "org.hibernate.type.TextType")
     @Field
-//    @XmlElementWrapper(name = "values", namespace = L10N_XML_NS)
     @XmlElement(name = "values", namespace = L10N_XML_NS)
     @XmlJavaTypeAdapter(LocalizedStringValuesAdapter.class)
     private Map<Locale, String> values;
diff --git a/ccm-core/src/main/java/org/libreccm/portation/AbstractMarshaller.java b/ccm-core/src/main/java/org/libreccm/portation/AbstractMarshaller.java
index 8514459c0..9afba1572 100644
--- a/ccm-core/src/main/java/org/libreccm/portation/AbstractMarshaller.java
+++ b/ccm-core/src/main/java/org/libreccm/portation/AbstractMarshaller.java
@@ -18,6 +18,7 @@
  */
 package org.libreccm.portation;
 
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.dataformat.xml.JacksonXmlModule;
diff --git a/ccm-core/src/main/java/org/libreccm/security/Group.java b/ccm-core/src/main/java/org/libreccm/security/Group.java
index 88f33fcdc..98b5b3120 100644
--- a/ccm-core/src/main/java/org/libreccm/security/Group.java
+++ b/ccm-core/src/main/java/org/libreccm/security/Group.java
@@ -104,7 +104,7 @@ public class Group extends Party implements Serializable, Portable {
      * The memberships of the group. For adding or removing memberships the
      * methods provided by the {@link GroupManager} should be used.
      */
-    @OneToMany(mappedBy = "group")
+    @OneToMany(mappedBy = "group", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "group-memberships", namespace = CORE_XML_NS)
     @XmlElement(name = "group-membership", namespace = CORE_XML_NS)
     @JsonIgnore
diff --git a/ccm-core/src/main/java/org/libreccm/security/Party.java b/ccm-core/src/main/java/org/libreccm/security/Party.java
index dcb12692f..3b88763cd 100644
--- a/ccm-core/src/main/java/org/libreccm/security/Party.java
+++ b/ccm-core/src/main/java/org/libreccm/security/Party.java
@@ -22,6 +22,7 @@ import com.fasterxml.jackson.annotation.JsonIdentityInfo;
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.ObjectIdGenerators;
 
+import javax.persistence.FetchType;
 import javax.validation.constraints.NotNull;
 import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlElementWrapper;
@@ -107,7 +108,7 @@ public class Party implements Serializable {
     /**
      * The role memberships the party.
      */
-    @OneToMany(mappedBy = "member")
+    @OneToMany(mappedBy = "member", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "role-memberships", namespace = CORE_XML_NS)
     @XmlElement(name = "role-membership", namespace = CORE_XML_NS)
     @JsonIgnore
diff --git a/ccm-core/src/main/java/org/libreccm/security/Role.java b/ccm-core/src/main/java/org/libreccm/security/Role.java
index 9766d0155..fe4a780a3 100644
--- a/ccm-core/src/main/java/org/libreccm/security/Role.java
+++ b/ccm-core/src/main/java/org/libreccm/security/Role.java
@@ -162,7 +162,7 @@ public class Role implements Serializable, Portable {
     /**
      * All memberships of the roles.
      */
-    @OneToMany(mappedBy = "role")
+    @OneToMany(mappedBy = "role", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "role-memberships", namespace = CORE_XML_NS)
     @XmlElement(name = "role-membership", namespace = CORE_XML_NS)
     @JsonIgnore
@@ -177,7 +177,7 @@ public class Role implements Serializable, Portable {
     @JsonIgnore
     private List<Permission> permissions = new ArrayList<>();
 
-    @OneToMany(mappedBy = "role")
+    @OneToMany(mappedBy = "role", fetch = FetchType.LAZY)
     @JsonIgnore
     private List<TaskAssignment> assignedTasks = new ArrayList<>();
 
diff --git a/ccm-core/src/main/java/org/libreccm/security/User.java b/ccm-core/src/main/java/org/libreccm/security/User.java
index 21f3604b1..809ca2354 100644
--- a/ccm-core/src/main/java/org/libreccm/security/User.java
+++ b/ccm-core/src/main/java/org/libreccm/security/User.java
@@ -195,7 +195,7 @@ public class User extends Party implements Serializable, Portable {
     /**
      * The groups of which the user is a member.
      */
-    @OneToMany(mappedBy = "member")
+    @OneToMany(mappedBy = "member", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "group-memberships", namespace = CORE_XML_NS)
     @XmlElement(name = "group-membership", namespace = CORE_XML_NS)
     @JsonIgnore
diff --git a/ccm-core/src/main/java/org/libreccm/web/CcmApplication.java b/ccm-core/src/main/java/org/libreccm/web/CcmApplication.java
index b76fceb50..632c25702 100644
--- a/ccm-core/src/main/java/org/libreccm/web/CcmApplication.java
+++ b/ccm-core/src/main/java/org/libreccm/web/CcmApplication.java
@@ -27,6 +27,7 @@ import org.libreccm.categorization.DomainOwnership;
 import org.libreccm.core.Resource;
 import org.libreccm.portation.Portable;
 
+import javax.persistence.FetchType;
 import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlElementWrapper;
 import javax.xml.bind.annotation.XmlRootElement;
@@ -97,7 +98,7 @@ public class CcmApplication extends Resource implements Serializable, Portable {
     /**
      * Category Domains owned by this {@code CcmObject}.
      */
-    @OneToMany(mappedBy = "owner")
+    @OneToMany(mappedBy = "owner", fetch = FetchType.LAZY)
     @XmlElementWrapper(name = "domains", namespace = WEB_XML_NS)
     @XmlElement(name = "domain", namespace = WEB_XML_NS)
     @JsonIgnore
diff --git a/ccm-core/src/main/java/org/libreccm/workflow/AssignableTask.java b/ccm-core/src/main/java/org/libreccm/workflow/AssignableTask.java
index 72188cac9..76db0c528 100644
--- a/ccm-core/src/main/java/org/libreccm/workflow/AssignableTask.java
+++ b/ccm-core/src/main/java/org/libreccm/workflow/AssignableTask.java
@@ -136,7 +136,7 @@ public class AssignableTask extends Task implements Serializable, Portable {
     /**
      * The roles to which task is assigned.
      */
-    @OneToMany(mappedBy = "task")
+    @OneToMany(mappedBy = "task", fetch = FetchType.LAZY)
     @JsonIgnore
     private List<TaskAssignment> assignments;
 
diff --git a/ccm-core/src/main/java/org/libreccm/workflow/Task.java b/ccm-core/src/main/java/org/libreccm/workflow/Task.java
index b36aa6cbf..ea38f6c10 100644
--- a/ccm-core/src/main/java/org/libreccm/workflow/Task.java
+++ b/ccm-core/src/main/java/org/libreccm/workflow/Task.java
@@ -153,16 +153,16 @@ public class Task implements Identifiable, Serializable {
     private Workflow workflow;
 
     /**
-     * Tasks which the depends of this task.
+     * Tasks which depend on this task.
      */
-    @ManyToMany(mappedBy = "dependsOn")
+    @ManyToMany(mappedBy = "dependsOn", fetch = FetchType.LAZY)
     @JsonIgnore
     private List<Task> dependentTasks;
 
     /**
-     * The task of this task depends.
+     * The dependencies of this task.
      */
-    @ManyToMany
+    @ManyToMany(fetch = FetchType.LAZY)
     @JoinTable(name = "WORKFLOW_TASK_DEPENDENCIES",
                schema = DB_SCHEMA,
                joinColumns = {
@@ -175,8 +175,9 @@ public class Task implements Identifiable, Serializable {
     /**
      * Comments for the task.
      */
-    @OneToMany
+    @OneToMany(fetch = FetchType.EAGER)
     @JoinColumn(name = "TASK_ID")
+    @JsonIdentityReference(alwaysAsId = true)
     private List<TaskComment> comments;
 
     public Task() {
diff --git a/ccm-core/src/main/java/org/libreccm/workflow/TaskComment.java b/ccm-core/src/main/java/org/libreccm/workflow/TaskComment.java
index 50a0efb4e..b8a77d345 100644
--- a/ccm-core/src/main/java/org/libreccm/workflow/TaskComment.java
+++ b/ccm-core/src/main/java/org/libreccm/workflow/TaskComment.java
@@ -19,6 +19,7 @@
 package org.libreccm.workflow;
 
 import com.fasterxml.jackson.annotation.JsonIdentityInfo;
+import com.fasterxml.jackson.annotation.JsonIdentityReference;
 import com.fasterxml.jackson.annotation.ObjectIdGenerators;
 import org.hibernate.annotations.Type;
 import org.libreccm.core.CoreConstants;
@@ -80,6 +81,7 @@ public class TaskComment implements Identifiable, Serializable, Portable {
      */
     @OneToOne
     @JoinColumn(name = "AUTHOR_ID")
+    @JsonIdentityReference(alwaysAsId = true)
     private User author;
 
     public long getCommentId() {
diff --git a/ccm-core/src/main/java/org/libreccm/workflow/Workflow.java b/ccm-core/src/main/java/org/libreccm/workflow/Workflow.java
index a1abaedd9..f65c7de0c 100644
--- a/ccm-core/src/main/java/org/libreccm/workflow/Workflow.java
+++ b/ccm-core/src/main/java/org/libreccm/workflow/Workflow.java
@@ -27,9 +27,27 @@ import org.libreccm.core.Identifiable;
 import org.libreccm.l10n.LocalizedString;
 import org.libreccm.portation.Portable;
 
-import javax.persistence.*;
+import javax.persistence.AssociationOverride;
+import javax.persistence.Column;
+import javax.persistence.Embedded;
+import javax.persistence.Entity;
+import javax.persistence.EnumType;
+import javax.persistence.Enumerated;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Inheritance;
+import javax.persistence.InheritanceType;
+import javax.persistence.JoinColumn;
+import javax.persistence.JoinTable;
+import javax.persistence.ManyToOne;
+import javax.persistence.NamedQueries;
+import javax.persistence.NamedQuery;
+import javax.persistence.OneToMany;
+import javax.persistence.OneToOne;
+import javax.persistence.Table;
 import javax.validation.constraints.NotNull;
-
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -38,8 +56,6 @@ import java.util.Objects;
 
 import static org.libreccm.core.CoreConstants.DB_SCHEMA;
 
-import java.util.Locale;
-
 /**
  * A workflow is a collection of tasks which are performed on an object. Tasks
  * can depend on each other.
@@ -92,6 +108,7 @@ public class Workflow implements Identifiable, Serializable, Portable {
      */
     @ManyToOne
     @JoinColumn(name = "TEMPLATE_ID")
+    @JsonIdentityReference(alwaysAsId = true)
     private Workflow template;
 
     /**
@@ -152,7 +169,7 @@ public class Workflow implements Identifiable, Serializable, Portable {
     /**
      * The tasks belonging to this workflow.
      */
-    @OneToMany(mappedBy = "workflow")
+    @OneToMany(mappedBy = "workflow", fetch = FetchType.LAZY)
     @JsonIgnore
     private List<Task> tasks;
 
@@ -244,9 +261,9 @@ public class Workflow implements Identifiable, Serializable, Portable {
     }
 
     protected void setObject(final CcmObject object) {
-        if (abstractWorkflow) {
+        if (abstractWorkflow && object != null) {
             throw new AbstractWorkflowException(String.format(
-                "Workflow %s is abstrct and can not assigned to an object.",
+                "Workflow %s is abstract and can not assigned to an object.",
                 uuid));
         }
         this.object = object;
diff --git a/ccm-core/src/main/java/org/libreccm/workflow/WorkflowRepository.java b/ccm-core/src/main/java/org/libreccm/workflow/WorkflowRepository.java
index fb15fc583..8e9dd044e 100644
--- a/ccm-core/src/main/java/org/libreccm/workflow/WorkflowRepository.java
+++ b/ccm-core/src/main/java/org/libreccm/workflow/WorkflowRepository.java
@@ -60,13 +60,13 @@ public class WorkflowRepository extends AbstractEntityRepository<Long, Workflow>
      *         the provided UUID.
      */
     public Optional<Workflow> findByUuid(final String uuid) {
-        if (uuid == null || uuid.trim().isEmpty()) {
+        if (uuid == null) {
             throw new IllegalArgumentException(
                 "The UUID of the Workflow to retrieve can't be null or empty.");
         }
         
-        final TypedQuery<Workflow> query = getEntityManager().createNamedQuery(
-            "Workflow.findByUuid", Workflow.class);
+        final TypedQuery<Workflow> query = getEntityManager()
+                .createNamedQuery("Workflow.findByUuid", Workflow.class);
         query.setParameter("uuid", uuid);
         
         try {
diff --git a/ccm-core/src/test/java/org/libreccm/portation/CoreDataImportTest.java b/ccm-core/src/test/java/org/libreccm/portation/CoreDataImportTest.java
index 0d5d434bc..a679ab98e 100644
--- a/ccm-core/src/test/java/org/libreccm/portation/CoreDataImportTest.java
+++ b/ccm-core/src/test/java/org/libreccm/portation/CoreDataImportTest.java
@@ -144,7 +144,6 @@ public class CoreDataImportTest {
 
         Assert.assertFalse(importHelper.importPermissions());
 
-//        Assert.assertFalse(importHelper.importWorkflowTemplates());
         Assert.assertFalse(importHelper.importWorkflows());
         Assert.assertFalse(importHelper.importTaskComments());
         //Assert.assertFalse(importHelper.importAssignableTasks());