diff --git a/include/CachePool.h b/include/CachePool.h
index a51e0dac68..c8530b0c13 100644
--- a/include/CachePool.h
+++ b/include/CachePool.h
@@ -1,3 +1,19 @@
+/* -------------------------------------------------------------------------- */
+/* Copyright 2002-2017, OpenNebula Project, OpenNebula Systems                */
+/*                                                                            */
+/* Licensed under the Apache License, Version 2.0 (the "License"); you may    */
+/* not use this file except in compliance with the License. You may obtain    */
+/* a copy of the License at                                                   */
+/*                                                                            */
+/* http://www.apache.org/licenses/LICENSE-2.0                                 */
+/*                                                                            */
+/* Unless required by applicable law or agreed to in writing, software        */
+/* distributed under the License is distributed on an "AS IS" BASIS,          */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   */
+/* See the License for the specific language governing permissions and        */
+/* limitations under the License.                                             */
+/* -------------------------------------------------------------------------- */
+
 #ifndef CACHE_POOL_H_
 #define CACHE_POOL_H_
 
@@ -12,29 +28,30 @@
 using namespace std;
 
 /**
- *  The Cache Pool class.
+ *  The Cache Pool class. This class is used to store volatile pool data.
  */
 template<typename T> class CachePool
 {
-private:
-
-    pthread_mutex_t resource_lock;
-
-    std::map<int, T *> resources;
-
 public:
-    CachePool(){
-        pthread_mutex_init(&resource_lock,0);
+    CachePool()
+    {
+        pthread_mutex_init(&resource_lock, 0);
     }
 
     ~CachePool()
     {
         typename std::map<int, T *>::iterator it;
 
+        pthread_mutex_lock(&resource_lock);
+
         for (it=resources.begin(); it != resources.end() ; ++it)
         {
             delete it->second;
         }
+
+        pthread_mutex_unlock(&resource_lock);
+
+        pthread_mutex_destroy(&resource_lock);
     };
 
     T * get_resource(int oid)
@@ -77,6 +94,12 @@ public:
 
         pthread_mutex_unlock(&resource_lock);
     }
+
+private:
+
+    pthread_mutex_t resource_lock;
+
+    std::map<int, T *> resources;
 };
 
 #endif /*CACHE_POOL_H_*/
\ No newline at end of file
diff --git a/include/HostPool.h b/include/HostPool.h
index 31b3ae5046..75d5f6a9c5 100644
--- a/include/HostPool.h
+++ b/include/HostPool.h
@@ -40,7 +40,7 @@ public:
         const string& hook_location, const string& remotes_location,
         time_t expire_time);
 
-    ~HostPool();
+    ~HostPool(){};
 
     /**
      *  Function to allocate a new Host object
@@ -320,15 +320,15 @@ private:
         set<int> prev_rediscovered_vms;
     };
 
-    pthread_mutex_t host_vm_lock;
-
     CachePool<HostVM> cache;
 
-    HostVM * get_host_vm(int oid){
+    HostVM * get_host_vm(int oid)
+    {
         return cache.get_resource(oid);
     }
 
-    void delete_host_vm(int oid){
+    void delete_host_vm(int oid)
+    {
         cache.delete_resource(oid);
     }
 
diff --git a/include/User.h b/include/User.h
index 1f6892e50c..e998077727 100644
--- a/include/User.h
+++ b/include/User.h
@@ -224,16 +224,6 @@ public:
         return groups.contains(_group_id);
     }
 
-    /**
-     *  Sets session token
-     *
-     *    @param session_token the new session token
-     */
-    void set_session(SessionToken * session_token)
-    {
-        session = session_token;
-    }
-
     // *************************************************************************
     // Quotas
     // *************************************************************************
@@ -381,7 +371,8 @@ protected:
         password(_password),
         auth_driver(_auth_driver),
         enabled(_enabled),
-        groups("GROUPS")
+        groups("GROUPS"),
+        session(0)
     {
         obj_template = new UserTemplate;
     };
diff --git a/include/UserPool.h b/include/UserPool.h
index 5e10ad620f..363359ec7e 100644
--- a/include/UserPool.h
+++ b/include/UserPool.h
@@ -86,7 +86,7 @@ public:
 
         if ( u != 0 )
         {
-            u->set_session(get_session_token(oid));
+            u->session = get_session_token(oid);
         }
 
         return u;
@@ -106,7 +106,7 @@ public:
 
         if ( u != 0 )
         {
-            u->set_session(get_session_token(u->oid));
+            u->session = get_session_token(u->oid);
         }
 
         return u;
@@ -237,13 +237,15 @@ private:
      **/
     static time_t _session_expiration_time;
 
-
     CachePool<SessionToken> cache;
-    SessionToken * get_session_token(int oid){
+
+    SessionToken * get_session_token(int oid)
+    {
         return cache.get_resource(oid);
     }
 
-    void delete_session_token(int oid){
+    void delete_session_token(int oid)
+    {
         cache.delete_resource(oid);
     }
 
diff --git a/src/host/HostPool.cc b/src/host/HostPool.cc
index 31b06cb2f9..4174fc4b86 100644
--- a/src/host/HostPool.cc
+++ b/src/host/HostPool.cc
@@ -140,18 +140,11 @@ HostPool::HostPool(SqlDB*                    db,
 
         add_hook(hook);
     }
-
-    pthread_mutex_init(&host_vm_lock,0);
 }
 
 /* -------------------------------------------------------------------------- */
 /* -------------------------------------------------------------------------- */
 
-HostPool::~HostPool(){};
-
-/* -------------------------------------------------------------------------- */
-/* -------------------------------------------------------------------------- */
-
 int HostPool::allocate (
     int * oid,
     const string& hostname,
diff --git a/src/um/UserPool.cc b/src/um/UserPool.cc
index aa497e25f5..01c0c89105 100644
--- a/src/um/UserPool.cc
+++ b/src/um/UserPool.cc
@@ -497,10 +497,8 @@ int UserPool::drop(PoolObjectSQL * objsql, string& error_msg)
         return -1;
     }
 
-    User * user = static_cast<User *>(objsql);
-    int oid = user->oid;
-
-    int rc = PoolSQL::drop(objsql, error_msg);
+    int oid = (static_cast<User *>(objsql))->oid;
+    int rc  = PoolSQL::drop(objsql, error_msg);
 
     if ( rc == 0 )
     {