diff --git a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/Volume.java b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/Volume.java
index 8a77bdbb8e..299e6d9c22 100644
--- a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/Volume.java
+++ b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/Volume.java
@@ -193,40 +193,46 @@ public class Volume {
       this.snapshotId = builder.snapshotId;
       this.name = builder.name;
       this.description = builder.description;
-      this.metadata = ImmutableMap.copyOf(builder.metadata);
+      this.metadata = ImmutableMap.copyOf(checkNotNull(builder.metadata, "metadata"));
    }
 
    /**
+    * @return the id of this volume
     */
    public String getId() {
       return this.id;
    }
 
    /**
+    * @return the status of this volume
     */
    public Status getStatus() {
       return this.status;
    }
 
    /**
+    * @return the size in GB of this volume
     */
    public int getSize() {
       return this.size;
    }
 
    /**
+    * @return the availabilityZone containing this volume
     */
    public String getZone() {
       return this.zone;
    }
 
    /**
+    * @return the time this volume was created
     */
    public Date getCreated() {
       return this.created;
    }
 
    /**
+    * @return the set of attachments (to Servers)
     */
    @Nullable
    public Set<VolumeAttachment> getAttachments() {
@@ -234,6 +240,7 @@ public class Volume {
    }
 
    /**
+    * @return the type of this volume
     */
    @Nullable
    public String getVolumeType() {
@@ -241,6 +248,7 @@ public class Volume {
    }
 
    /**
+    * @return the snapshot id this volume is associated with.
     */
    @Nullable
    public String getSnapshotId() {
@@ -248,6 +256,7 @@ public class Volume {
    }
 
    /**
+    * @return the name of this volume - as displayed in the openstack console
     */
    @Nullable
    public String getName() {
@@ -255,14 +264,13 @@ public class Volume {
    }
 
    /**
+    * @return the description of this volume - as displayed in the openstack console
     */
    @Nullable
    public String getDescription() {
       return this.description;
    }
    
-   /**
-    */
    @Nullable
    public Map<String, String> getMetadata() {
       return Collections.unmodifiableMap(this.metadata);
diff --git a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeAttachment.java b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeAttachment.java
index ef93d9d18b..b6a231d7d1 100644
--- a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeAttachment.java
+++ b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeAttachment.java
@@ -18,13 +18,15 @@
  */
 package org.jclouds.openstack.nova.v1_1.domain;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import org.jclouds.javax.annotation.Nullable;
 
 import com.google.common.base.Objects;
 import com.google.common.base.Objects.ToStringHelper;
 
 /**
- * An Openstack Nova Volume Attachment
+ * An Openstack Nova Volume Attachment (describes how Volumes are attached to Servers)
  */
 public class VolumeAttachment {
 
@@ -92,27 +94,28 @@ public class VolumeAttachment {
    private final String device;
 
    protected VolumeAttachment(Builder<?> builder) {
-      this.id = builder.id;
-      this.volumeId = builder.volumeId;
+      this.id = checkNotNull(builder.id, "id");
+      this.volumeId = checkNotNull(builder.volumeId, "volumeId");
       this.serverId = builder.serverId;
       this.device = builder.device;
    }
 
    /**
+    * @return the attachment id (typically the same as #getVolumeId())
     */
-   @Nullable
    public String getId() {
       return this.id;
    }
 
    /**
+    * @return the id of the volume attached
     */
-   @Nullable
    public String getVolumeId() {
       return this.volumeId;
    }
 
    /**
+    * @return the id of the server the volume is attached to
     */
    @Nullable
    public String getServerId() {
@@ -120,6 +123,7 @@ public class VolumeAttachment {
    }
 
    /**
+    * @return the device name (e.g. "/dev/vdc")
     */
    @Nullable
    public String getDevice() {
diff --git a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeSnapshot.java b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeSnapshot.java
index fa7ca86cb8..b20d47c467 100644
--- a/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeSnapshot.java
+++ b/apis/openstack-nova/src/main/java/org/jclouds/openstack/nova/v1_1/domain/VolumeSnapshot.java
@@ -18,6 +18,8 @@
  */
 package org.jclouds.openstack.nova.v1_1.domain;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import java.util.Date;
 
 import org.jclouds.javax.annotation.Nullable;
@@ -122,9 +124,9 @@ public class VolumeSnapshot {
    private final String description;
 
    protected VolumeSnapshot(Builder<?> builder) {
-      this.id = builder.id;
-      this.volumeId = builder.volumeId;
-      this.status = builder.status;
+      this.id = checkNotNull(builder.id, "id");
+      this.volumeId = checkNotNull(builder.volumeId, "volumeId");
+      this.status = checkNotNull(builder.status, "status");
       this.size = builder.size;
       this.created = builder.created;
       this.name = builder.name;
@@ -132,34 +134,35 @@ public class VolumeSnapshot {
    }
 
    /**
+    * @return the id of this snapshot
     */
-   @Nullable
    public String getId() {
       return this.id;
    }
 
    /**
+    * @return the id of the Volume this snapshot was taken from
     */
-   @Nullable
    public String getVolumeId() {
       return this.volumeId;
    }
 
    /**
+    * @return the status of this snapshot
     */
-   @Nullable
    public Volume.Status getStatus() {
       return this.status;
    }
 
    /**
+    * @return the size in GB of the volume this snapshot was taken from
     */
-   @Nullable
    public int getSize() {
       return this.size;
    }
 
    /**
+    * @return the data the snapshot was taken
     */
    @Nullable
    public Date getCreated() {
@@ -167,13 +170,16 @@ public class VolumeSnapshot {
    }
 
    /**
+    * @return the name of this snapshot - as displayed in the openstack console
     */
    @Nullable
    public String getName() {
       return this.name;
    }
 
+
    /**
+    * @return the description of this snapshot - as displayed in the openstack console
     */
    @Nullable
    public String getDescription() {