diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Actions.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Actions.java
index 396aec968f..5633403e8e 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Actions.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Actions.java
@@ -26,6 +26,8 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * Wraps individual Action elements.
  * Needed because parsing is done with JAXB and it does not handle Generic collections
@@ -38,6 +40,7 @@ public class Actions {
 
     @XmlElement(name = "Action")
     void setAction(Action action) {
+        checkNotNull(action,"action");
         this.actions.add(action);
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/AssignedIpAddresses.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/AssignedIpAddresses.java
index f808bd515d..3c34b37b69 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/AssignedIpAddresses.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/AssignedIpAddresses.java
@@ -23,6 +23,8 @@ import org.jclouds.tmrk.enterprisecloud.domain.internal.BaseResource;
 import javax.xml.bind.annotation.XmlElement;
 import java.net.URI;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * @author Jason King
  */
@@ -31,13 +33,15 @@ public class AssignedIpAddresses extends BaseResource<AssignedIpAddresses> {
    //TODO builder stuff
 
    @XmlElement(name = "Actions", required = true)
-   private Actions actions;
+   private Actions actions = new Actions();
 
    @XmlElement(name = "Networks", required = true)
-   private DeviceNetworks networks;
+   private DeviceNetworks networks = new DeviceNetworks();
 
    public AssignedIpAddresses(URI href, String type, Actions actions, DeviceNetworks networks) {
       super(href, type);
+      checkNotNull(actions,"actions");
+      checkNotNull(networks,"networks");
    }
 
    protected AssignedIpAddresses() {
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceIps.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceIps.java
index fbb9315e7b..58db0bb378 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceIps.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceIps.java
@@ -25,6 +25,9 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.jclouds.util.Preconditions2.checkNotEmpty;
+
 /**
  * Wraps individual IpAddresses
  * @author Jason King
@@ -39,6 +42,8 @@ public class DeviceIps {
 
     @XmlElement(name = "IpAddress")
     void setIpAddress(String ipAddress) {
+        checkNotNull(ipAddress,"ipAddress");
+        checkNotEmpty(ipAddress, "ipAddress");
         this.ipAddresses.add(ipAddress);
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetwork.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetwork.java
index 0ed42ff4c1..8f82630b51 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetwork.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetwork.java
@@ -29,7 +29,7 @@ import javax.xml.bind.annotation.XmlElement;
 public class DeviceNetwork extends BaseNamedResource<DeviceNetwork> {
 
    @XmlElement(name = "IpAddresses")
-   private DeviceIps ipAddresses;
+   private DeviceIps ipAddresses = new DeviceIps();
 
    protected DeviceNetwork() {
        //For JAXB
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetworks.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetworks.java
index 716c9961d1..07f1282fe8 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetworks.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/DeviceNetworks.java
@@ -25,6 +25,8 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * Container for DeviceNetwork items
  * @author Jason King
@@ -39,6 +41,7 @@ public class DeviceNetworks {
 
     @XmlElement(name = "Network")
     void setDeviceNetwork(DeviceNetwork deviceNetwork) {
+        checkNotNull(deviceNetwork,"deviceNetwork");
         this.deviceNetworks.add(deviceNetwork);
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Disks.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Disks.java
index c660876b04..ccfcaa171a 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Disks.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Disks.java
@@ -26,6 +26,8 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * Wraps individual Disk elements.
  * Needed because parsing is done with JAXB and it does not handle Generic collections
@@ -38,6 +40,7 @@ public class Disks {
 
     @XmlElement(name = "Disk")
     public void setVirtualDisk(VirtualDisk disk) {
+        checkNotNull(disk,"disk");
         this.disks.add(disk);
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/HardwareConfiguration.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/HardwareConfiguration.java
index 7c55a63f99..e01f73ad80 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/HardwareConfiguration.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/HardwareConfiguration.java
@@ -51,17 +51,17 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
 
    public static class Builder extends BaseResource.Builder<HardwareConfiguration> {
 
-       private Actions actions;
+       private Actions actions = new Actions();
        private int processorCount;
        private Memory memory;
-       private Disks disks;
-       private Nics nics;
+       private Disks disks = new Disks();
+       private Nics nics = new Nics();
 
        /**
         * @see HardwareConfiguration#getActions
         */
        public Builder actions(Set<Action> actions) {
-          this.actions = new Actions();
+          checkNotNull(actions,"actions");
           for(Action action:actions) this.actions.setAction(action);
           return this;
        }
@@ -86,7 +86,7 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
         * @see HardwareConfiguration#getDisks
         */
        public Builder disks(Disks disks) {
-          this.disks = disks;
+          this.disks = checkNotNull(disks,"disks");;
           return this;
        }
 
@@ -94,7 +94,7 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
         * @see HardwareConfiguration#getDisks
         */
        public Builder nics(Nics nics) {
-          this.nics = nics;
+          this.nics = checkNotNull(nics,"nics");;
           return this;
        }
 
@@ -145,7 +145,7 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
    }
 
    @XmlElement(name = "Actions", required = false)
-   private Actions actions;
+   private Actions actions = new Actions();
 
    @XmlElement(name = "ProcessorCount", required = true)
    private int processorCount;
@@ -154,17 +154,17 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
    private Memory memory;
 
    @XmlElement(name = "Disks", required = false)
-   private Disks disks;
+   private Disks disks = new Disks();
 
    @XmlElement(name = "Nics", required = false)
-   private Nics nics;
+   private Nics nics = new Nics();
 
-   public HardwareConfiguration(@Nullable Actions actions, int processorCount, @Nullable Memory memory, @Nullable Disks disks, @Nullable Nics nics) {
+   public HardwareConfiguration(Actions actions, int processorCount, @Nullable Memory memory, Disks disks, Nics nics) {
        this.actions = checkNotNull(actions, "actions");
        this.processorCount = processorCount;
        this.memory = memory;
-       this.disks = disks;
-       this.nics = nics;
+       this.disks = checkNotNull(disks, "disks");
+       this.nics = checkNotNull(nics, "nics");
    }
 
     protected HardwareConfiguration() {
@@ -200,14 +200,11 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
         HardwareConfiguration that = (HardwareConfiguration) o;
 
         if (processorCount != that.processorCount) return false;
-        if (actions != null ? !actions.equals(that.actions) : that.actions != null)
-            return false;
-        if (disks != null ? !disks.equals(that.disks) : that.disks != null)
-            return false;
+        if (!actions.equals(that.actions)) return false;
+        if (!disks.equals(that.disks)) return false;
         if (memory != null ? !memory.equals(that.memory) : that.memory != null)
             return false;
-        if (nics != null ? !nics.equals(that.nics) : that.nics != null)
-            return false;
+        if (!nics.equals(that.nics)) return false;
 
         return true;
     }
@@ -215,11 +212,11 @@ public class HardwareConfiguration extends BaseResource<HardwareConfiguration> {
     @Override
     public int hashCode() {
         int result = super.hashCode();
-        result = 31 * result + (actions != null ? actions.hashCode() : 0);
+        result = 31 * result + actions.hashCode();
         result = 31 * result + processorCount;
         result = 31 * result + (memory != null ? memory.hashCode() : 0);
-        result = 31 * result + (disks != null ? disks.hashCode() : 0);
-        result = 31 * result + (nics != null ? nics.hashCode() : 0);
+        result = 31 * result + disks.hashCode();
+        result = 31 * result + nics.hashCode();
         return result;
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Layout.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Layout.java
index 97fbcacc6f..c1e165df48 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Layout.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Layout.java
@@ -18,6 +18,8 @@
  */
 package org.jclouds.tmrk.enterprisecloud.domain;
 
+import org.jclouds.javax.annotation.Nullable;
+
 import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlRootElement;
 
@@ -38,7 +40,7 @@ public class Layout {
     @XmlElement(name = "Row")
     private Row row;
 
-    public Layout(Group group, Row row) {
+    public Layout(@Nullable Group group, @Nullable Row row) {
         this.group = group;
         this.row = row;
     }
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/NetworkReference.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/NetworkReference.java
index 815b964c63..bc3f6de685 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/NetworkReference.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/NetworkReference.java
@@ -135,7 +135,7 @@ public class NetworkReference extends BaseNamedResource<NetworkReference> {
    @XmlElement(name = "NetworkType")
    private NetworkType networkType;
 
-   public NetworkReference(URI href, String type, String name, NetworkType networkType) {
+   public NetworkReference(URI href, String type, String name,@Nullable NetworkType networkType) {
       super(href, type, name);
       this.networkType = networkType;
    }
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Tasks.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Tasks.java
index 662b58061a..6edd16c4ec 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Tasks.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/Tasks.java
@@ -26,6 +26,8 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * Wraps individual Task elements.
  * Needed because parsing is done with JAXB and it does not handle Generic collections
@@ -38,6 +40,7 @@ public class Tasks {
 
     @XmlElement(name = "Task")
     public void setTask(Task task) {
+        checkNotNull(task,"task");
         tasks.add(task);
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachine.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachine.java
index 6c72ce5782..ed53132ccf 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachine.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachine.java
@@ -57,9 +57,9 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
    }
 
    public static class Builder extends BaseNamedResource.Builder<VirtualMachine> {
-      private Links links;
-      private Actions actions;
-      private Tasks tasks;
+      private Links links = new Links();
+      private Actions actions = new Actions();
+      private Tasks tasks = new Tasks();
       private String description;
       private VirtualMachineStatus status;
 
@@ -70,13 +70,13 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
       private boolean customizationPending;
       private OperatingSystem operatingSystem;
       private HardwareConfiguration hardwareConfiguration;
-      private VirtualMachineIpAddresses ipAddresses;
+      private VirtualMachineIpAddresses ipAddresses = new VirtualMachineIpAddresses();
 
       /**
        * @see VirtualMachine#getLinks
        */
       public Builder links(Set<Link> links) {
-         this.links = new Links();
+         checkNotNull(links,"links");
          for(Link link:links) this.links.setLink(link);
          return this;
       }
@@ -85,7 +85,7 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
         * @see VirtualMachine#getActions
         */
        public Builder actions(Set<Action> actions) {
-          this.actions = new Actions();
+          checkNotNull(actions,"actions");
           for(Action action:actions) this.actions.setAction(action);
           return this;
        }
@@ -94,7 +94,7 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
         * @see VirtualMachine#getTasks
         */
        public Builder tasks(Set<Task> tasks) {
-          this.tasks = new Tasks();
+          checkNotNull(tasks,"tasks");
           for(Task task: tasks) this.tasks.setTask(task);
           return this;
        }
@@ -184,7 +184,7 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
         * @see VirtualMachine#getIpAddresses()
         */
        public Builder ipAddresses(VirtualMachineIpAddresses ipAddresses) {
-          this.ipAddresses = ipAddresses;
+          this.ipAddresses = checkNotNull(ipAddresses,"ipAddresses");
           return this;
        }
 
@@ -264,13 +264,13 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
    }
 
    @XmlElement(name = "Links", required = true)
-   private Links links;
+   private Links links = new Links();
 
    @XmlElement(name = "Tasks", required = true)
-   private Tasks tasks;
+   private Tasks tasks = new Tasks();
 
    @XmlElement(name = "Actions", required = true)
-   private Actions actions;
+   private Actions actions = new Actions();
 
    @XmlElement(name = "Description", required = true)
    private String description;
@@ -300,7 +300,7 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
    private HardwareConfiguration hardwareConfiguation;
 
    @XmlElement(name = "IpAddresses", required = false)
-   private VirtualMachineIpAddresses ipAddresses;
+   private VirtualMachineIpAddresses ipAddresses = new VirtualMachineIpAddresses();
 
     public VirtualMachine(URI href, String type, String name, Tasks tasks, Actions actions, Links links, String description, @Nullable Layout layout,
                          VirtualMachineStatus status, boolean poweredOn, @Nullable ToolsStatus toolsStatus, @Nullable VirtualMachineMediaStatus mediaStatus, boolean customizationPending,
@@ -319,7 +319,7 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
       this.customizationPending = customizationPending;
       this.operatingSystem = operatingSystem;
       this.hardwareConfiguation = hardwareConfiguration;
-      this.ipAddresses = ipAddresses;
+      this.ipAddresses = checkNotNull(ipAddresses, "ipAddresses");
    }
 
    protected VirtualMachine() {
@@ -393,9 +393,6 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
        return operatingSystem;
    }
 
-    /**
-     * Is optional, so may return null
-     */
    public VirtualMachineIpAddresses getIpAddresses() {
        return ipAddresses;
    }
@@ -411,11 +408,11 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
         if (customizationPending != that.customizationPending) return false;
         if (poweredOn != that.poweredOn) return false;
         if (!actions.equals(that.actions)) return false;
-        if (!description.equals(that.description)) return false;
+        if (description != null ? !description.equals(that.description) : that.description != null)
+            return false;
         if (hardwareConfiguation != null ? !hardwareConfiguation.equals(that.hardwareConfiguation) : that.hardwareConfiguation != null)
             return false;
-        if (ipAddresses != null ? !ipAddresses.equals(that.ipAddresses) : that.ipAddresses != null)
-            return false;
+        if (!ipAddresses.equals(that.ipAddresses)) return false;
         if (layout != null ? !layout.equals(that.layout) : that.layout != null)
             return false;
         if (!links.equals(that.links)) return false;
@@ -435,16 +432,16 @@ public class VirtualMachine extends BaseNamedResource<VirtualMachine> {
         result = 31 * result + links.hashCode();
         result = 31 * result + tasks.hashCode();
         result = 31 * result + actions.hashCode();
-        result = 31 * result + description.hashCode();
+        result = 31 * result + (description != null ? description.hashCode() : 0);
         result = 31 * result + (layout != null ? layout.hashCode() : 0);
-        result = 31 * result + status.hashCode();
+        result = 31 * result + (status != null ? status.hashCode() : 0);
         result = 31 * result + (poweredOn ? 1 : 0);
         result = 31 * result + (toolsStatus != null ? toolsStatus.hashCode() : 0);
         result = 31 * result + (mediaStatus != null ? mediaStatus.hashCode() : 0);
         result = 31 * result + (customizationPending ? 1 : 0);
         result = 31 * result + (operatingSystem != null ? operatingSystem.hashCode() : 0);
         result = 31 * result + (hardwareConfiguation != null ? hardwareConfiguation.hashCode() : 0);
-        result = 31 * result + (ipAddresses != null ? ipAddresses.hashCode() : 0);
+        result = 31 * result + ipAddresses.hashCode();
         return result;
     }
 
diff --git a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachineIpAddresses.java b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachineIpAddresses.java
index e6a89437cc..0ae352ad2f 100644
--- a/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachineIpAddresses.java
+++ b/sandbox-providers/tmrk-enterprisecloud/src/main/java/org/jclouds/tmrk/enterprisecloud/domain/VirtualMachineIpAddresses.java
@@ -32,7 +32,7 @@ import java.util.Set;
 public class VirtualMachineIpAddresses {
 
     @XmlElement(name = "AssignedIpAddresses")
-    private AssignedIpAddresses assignedIpAddresses;
+    private AssignedIpAddresses assignedIpAddresses = new AssignedIpAddresses();
 
     protected VirtualMachineIpAddresses() {
         // For JAXB