diff --git a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOCache.java b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOCache.java
index 1c3135e5ac..4e903b0112 100644
--- a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOCache.java
+++ b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOCache.java
@@ -18,9 +18,7 @@
  */
 package org.alfresco.module.org_alfresco_module_rm.caveat.dao;
 
-import java.io.Serializable;
-import java.util.Map;
-
+import com.google.common.collect.ImmutableMap;
 import org.alfresco.module.org_alfresco_module_rm.caveat.scheme.CaveatGroup;
 
 /**
@@ -29,18 +27,18 @@ import org.alfresco.module.org_alfresco_module_rm.caveat.scheme.CaveatGroup;
  * @author Tom Page
  * @since 2.4.a
  */
-public class CaveatDAOCache<SMAP extends Map<String, CaveatGroup> & Serializable> implements CaveatDAOInterface<SMAP>
+public class CaveatDAOCache implements CaveatDAOInterface
 {
     /** The wrapped caveat DAO. */
-    private CaveatDAOInterface<SMAP> caveatDAO;
+    private CaveatDAOInterface caveatDAO;
     /** A cache of the system caveat groups. */
-    private SMAP caveatGroups;
+    private ImmutableMap<String, CaveatGroup> caveatGroups;
 
     /**
      * {@inheritDoc} The first call to this method will be cached and returned for every successive call.
      */
     @Override
-    public SMAP getCaveatGroups()
+    public ImmutableMap<String, CaveatGroup> getCaveatGroups()
     {
         if (caveatGroups == null)
         {
@@ -54,7 +52,7 @@ public class CaveatDAOCache<SMAP extends Map<String, CaveatGroup> & Serializable
      *
      * @param caveatDAO The caveat DAO to be wrapped.
      */
-    public void setCaveatDAO(CaveatDAOInterface<SMAP> caveatDAO)
+    public void setCaveatDAO(CaveatDAOInterface caveatDAO)
     {
         this.caveatDAO = caveatDAO;
     }
diff --git a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSON.java b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSON.java
index 8d6fa67634..8e9a8aa43e 100644
--- a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSON.java
+++ b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSON.java
@@ -21,14 +21,13 @@ package org.alfresco.module.org_alfresco_module_rm.caveat.dao;
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.Serializable;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMap.Builder;
 import org.alfresco.module.org_alfresco_module_rm.caveat.CaveatException.MalformedConfiguration;
 import org.alfresco.module.org_alfresco_module_rm.caveat.scheme.CaveatGroup;
 import org.alfresco.module.org_alfresco_module_rm.caveat.scheme.CaveatGroupType;
@@ -47,7 +46,7 @@ import org.slf4j.LoggerFactory;
  * @author Tom Page
  * @since 2.4.a
  */
-public class CaveatDAOFromJSON<SMAP extends Map<String, CaveatGroup> & Serializable> implements CaveatDAOInterface<SMAP>
+public class CaveatDAOFromJSON implements CaveatDAOInterface
 {
     /** JSON key for the group id. */
     private static final String GROUP_ID_JSON_KEY = "id";
@@ -81,10 +80,9 @@ public class CaveatDAOFromJSON<SMAP extends Map<String, CaveatGroup> & Serializa
      * @throws MalformedConfiguration If the configuration file cannot be interpreted.
      */
     @Override
-    public SMAP getCaveatGroups()
+    public ImmutableMap<String, CaveatGroup> getCaveatGroups()
     {
-        @SuppressWarnings("unchecked")
-        SMAP result = (SMAP) new HashMap<String, CaveatGroup>();
+        Builder<String, CaveatGroup> builder = ImmutableMap.builder();
         try (final InputStream in = this.getClass().getResourceAsStream(configLocation))
         {
             if (in != null)
@@ -97,9 +95,7 @@ public class CaveatDAOFromJSON<SMAP extends Map<String, CaveatGroup> & Serializa
                     final JSONObject nextObj = jsonArray.getJSONObject(i);
                     CaveatGroup caveatGroup = createGroup(nextObj);
                     String caveatGroupId = caveatGroup.getId();
-                    if (result.containsKey(caveatGroupId)) { throw new MalformedConfiguration(
-                                "Configuration contains two caveat groups with id " + caveatGroupId); }
-                    result.put(caveatGroupId, caveatGroup);
+                    builder.put(caveatGroupId, caveatGroup);
                 }
             }
             else
@@ -111,7 +107,17 @@ public class CaveatDAOFromJSON<SMAP extends Map<String, CaveatGroup> & Serializa
         {
             throw new MalformedConfiguration("Could not read caveat configuration: " + configLocation, e);
         }
-        return result;
+
+        ImmutableMap<String, CaveatGroup> map;
+        try
+        {
+            map = builder.build();
+        }
+        catch (IllegalArgumentException e)
+        {
+            throw new MalformedConfiguration("Configuration contains two caveat groups with the same id.", e);
+        }
+        return map;
     }
 
     /**
diff --git a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONBootstrap.java b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONBootstrap.java
index 3d98844a5a..71a266bd97 100644
--- a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONBootstrap.java
+++ b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONBootstrap.java
@@ -23,6 +23,7 @@ import static org.alfresco.module.org_alfresco_module_rm.caveat.CaveatConstants.
 import java.io.Serializable;
 import java.util.Map;
 
+import com.google.common.collect.ImmutableMap;
 import org.alfresco.module.org_alfresco_module_rm.caveat.CaveatException.MalformedConfiguration;
 import org.alfresco.module.org_alfresco_module_rm.caveat.scheme.CaveatGroup;
 import org.alfresco.module.org_alfresco_module_rm.util.AuthenticationUtil;
@@ -41,7 +42,7 @@ import org.springframework.extensions.surf.util.AbstractLifecycleBean;
  * @author Tom Page
  * @since 2.4.a
  */
-public class CaveatDAOFromJSONBootstrap<SMAP extends Map<String, CaveatGroup> & Serializable> extends AbstractLifecycleBean
+public class CaveatDAOFromJSONBootstrap extends AbstractLifecycleBean
 {
     /** Logging utility for the class. */
     private static final Logger LOGGER = LoggerFactory.getLogger(CaveatDAOFromJSONBootstrap.class);
@@ -49,14 +50,14 @@ public class CaveatDAOFromJSONBootstrap<SMAP extends Map<String, CaveatGroup> &
     private final AuthenticationUtil authenticationUtil;
     private final TransactionService transactionService;
     private AttributeService attributeService;
-    private CaveatDAOInterface<SMAP> caveatDAO;
+    private CaveatDAOInterface caveatDAO;
 
     private boolean isInitialised = false;
 
     public CaveatDAOFromJSONBootstrap(AuthenticationUtil authUtil,
                                       TransactionService txService,
                                       AttributeService attributeService,
-                                      CaveatDAOInterface<SMAP> caveatDAO)
+                                      CaveatDAOInterface caveatDAO)
     {
         this.authenticationUtil = authUtil;
         this.transactionService = txService;
@@ -65,7 +66,7 @@ public class CaveatDAOFromJSONBootstrap<SMAP extends Map<String, CaveatGroup> &
     }
 
     /** Set the object from which configuration options will be read. */
-    public void setClassificationServiceDAO(CaveatDAOInterface<SMAP> caveatDAO) { this.caveatDAO = caveatDAO; }
+    public void setClassificationServiceDAO(CaveatDAOInterface caveatDAO) { this.caveatDAO = caveatDAO; }
     public void setAttributeService(AttributeService attributeService) { this.attributeService = attributeService; }
 
     public boolean isInitialised()
@@ -99,15 +100,15 @@ public class CaveatDAOFromJSONBootstrap<SMAP extends Map<String, CaveatGroup> &
      *
      * @return the persisted caveat groups if they have been persisted, else {@code null}.
      */
-    private SMAP getPersistedCaveatGroups(final Serializable[] key)
+    private ImmutableMap<String, CaveatGroup> getPersistedCaveatGroups(final Serializable[] key)
     {
-        return authenticationUtil.runAsSystem(new RunAsWork<SMAP>()
+        return authenticationUtil.runAsSystem(new RunAsWork<ImmutableMap<String, CaveatGroup>>()
         {
             @Override
             @SuppressWarnings("unchecked")
-            public SMAP doWork() throws Exception
+            public ImmutableMap<String, CaveatGroup> doWork() throws Exception
             {
-                return (SMAP) attributeService.getAttribute(key);
+                return (ImmutableMap<String, CaveatGroup>) attributeService.getAttribute(key);
             }
         });
     }
@@ -133,8 +134,8 @@ public class CaveatDAOFromJSONBootstrap<SMAP extends Map<String, CaveatGroup> &
      */
     protected void initialiseConfiguredCaveatGroups(Serializable[] key)
     {
-        final SMAP persistedGroups = getPersistedCaveatGroups(key);
-        final SMAP classpathGroups = caveatDAO.getCaveatGroups();
+        final ImmutableMap<String, CaveatGroup> persistedGroups = getPersistedCaveatGroups(key);
+        final ImmutableMap<String, CaveatGroup> classpathGroups = caveatDAO.getCaveatGroups();
 
         // Note! We cannot log the entities or even the size of these lists for security reasons.
         LOGGER.debug("Persisted CaveatGroup: {}", loggableStatusOf(persistedGroups));
diff --git a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOInterface.java b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOInterface.java
index 5001f3b05b..6f48422949 100644
--- a/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOInterface.java
+++ b/rm-server/source/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOInterface.java
@@ -19,21 +19,20 @@
 
 package org.alfresco.module.org_alfresco_module_rm.caveat.dao;
 
-import java.io.Serializable;
-import java.util.Map;
-
+import com.google.common.collect.ImmutableMap;
 import org.alfresco.module.org_alfresco_module_rm.caveat.scheme.CaveatGroup;
 
+
 /**
  * An object responsible for providing access to the configured caveat groups and marks.
  *
  * @author Tom Page
  * @since 2.4.a
  */
-public interface CaveatDAOInterface<SMAP extends Map<String, CaveatGroup> & Serializable>
+public interface CaveatDAOInterface
 {
     /**
      * Gets a map of all the available caveat groups keyed by id.
      */
-    SMAP getCaveatGroups();
+    ImmutableMap<String, CaveatGroup> getCaveatGroups();
 }
diff --git a/rm-server/unit-test/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONUnitTest.java b/rm-server/unit-test/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONUnitTest.java
index c6d4139b74..f6f6e70fc4 100644
--- a/rm-server/unit-test/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONUnitTest.java
+++ b/rm-server/unit-test/java/org/alfresco/module/org_alfresco_module_rm/caveat/dao/CaveatDAOFromJSONUnitTest.java
@@ -37,8 +37,7 @@ import org.junit.Test;
 public class CaveatDAOFromJSONUnitTest
 {
     /** The class under test. */
-    @SuppressWarnings("rawtypes")
-    CaveatDAOFromJSON<?> caveatDAOFromJSON = new CaveatDAOFromJSON();
+    CaveatDAOFromJSON caveatDAOFromJSON = new CaveatDAOFromJSON();
 
     /** Test that loading the default caveat configuration file doesn't throw any exceptions. */
     @Test