diff --git a/src/nl/astraeus/database/ObjectPersister.java b/src/nl/astraeus/database/ObjectPersister.java
index c3fd8b4..ec2eec6 100644
--- a/src/nl/astraeus/database/ObjectPersister.java
+++ b/src/nl/astraeus/database/ObjectPersister.java
@@ -20,6 +20,9 @@
 
     public void insert(Object object) {
         metaData.insert(object);
+
+        Long id = metaData.getId(object);
+        Cache.get().set((Class<Object>) object.getClass(), id, object);
     }
 
     public void update(Object object) {

diff --git a/src/nl/astraeus/database/ObjectPersister.java b/src/nl/astraeus/database/ObjectPersister.java
index c3fd8b4..ec2eec6 100644
--- a/src/nl/astraeus/database/ObjectPersister.java
+++ b/src/nl/astraeus/database/ObjectPersister.java
@@ -20,6 +20,9 @@
 
     public void insert(Object object) {
         metaData.insert(object);
+
+        Long id = metaData.getId(object);
+        Cache.get().set((Class<Object>) object.getClass(), id, object);
     }
 
     public void update(Object object) {
diff --git a/src/nl/astraeus/database/jdbc/ConnectionPool.java b/src/nl/astraeus/database/jdbc/ConnectionPool.java
index 5265dc4..ca163a6 100644
--- a/src/nl/astraeus/database/jdbc/ConnectionPool.java
+++ b/src/nl/astraeus/database/jdbc/ConnectionPool.java
@@ -23,9 +23,10 @@
     private ConnectionProvider connectionProvider = null;
 
     private List<ConnectionWrapper> connectionPool = new LinkedList<>();
+    private List<ConnectionWrapper> usedPool = new LinkedList<>();
+
     private int minimumNumberOfConnections = 0;
     private int maximumNumberOfConnections = 20;
-    private int used = 0;
 
     public ConnectionPool() {
     }
@@ -46,10 +47,10 @@
     }
 
     public synchronized Connection getConnection() {
-        if (connectionPool.isEmpty() && used < maximumNumberOfConnections) {
+        if (connectionPool.isEmpty() && usedPool.size() < maximumNumberOfConnections) {
             ConnectionWrapper wrapper = new ConnectionWrapper(this, connectionProvider.getConnection());
 
-            used++;
+            usedPool.add(wrapper);
             return wrapper;
         }
 
@@ -62,14 +63,20 @@
             }
         }
 
-        used++;
-        return connectionPool.remove(0);
+        ConnectionWrapper result = connectionPool.remove(0);
+        usedPool.add(result);
+        return result;
     }
 
     protected synchronized void returnConnection(ConnectionWrapper connection) {
-        used--;
-        connectionPool.add(connection);
-        notify();
+        if (usedPool.contains(connection)) {
+            usedPool.remove(connection);
+            connectionPool.add(connection);
+            notify();
+        } else {
+            // discard (clear was probably called)
+            connection.dispose();
+        }
     }
 
     public boolean hasConnectionProvider() {
@@ -77,6 +84,11 @@
     }
 
     public synchronized void clear() {
-        connectionPool = new LinkedList<>();
+        connectionPool.clear();
+        usedPool.clear();
+    }
+
+    public ConnectionProvider getProvider() {
+        return connectionProvider;
     }
 }

diff --git a/src/nl/astraeus/database/ObjectPersister.java b/src/nl/astraeus/database/ObjectPersister.java
index c3fd8b4..ec2eec6 100644
--- a/src/nl/astraeus/database/ObjectPersister.java
+++ b/src/nl/astraeus/database/ObjectPersister.java
@@ -20,6 +20,9 @@
 
     public void insert(Object object) {
         metaData.insert(object);
+
+        Long id = metaData.getId(object);
+        Cache.get().set((Class<Object>) object.getClass(), id, object);
     }
 
     public void update(Object object) {
diff --git a/src/nl/astraeus/database/jdbc/ConnectionPool.java b/src/nl/astraeus/database/jdbc/ConnectionPool.java
index 5265dc4..ca163a6 100644
--- a/src/nl/astraeus/database/jdbc/ConnectionPool.java
+++ b/src/nl/astraeus/database/jdbc/ConnectionPool.java
@@ -23,9 +23,10 @@
     private ConnectionProvider connectionProvider = null;
 
     private List<ConnectionWrapper> connectionPool = new LinkedList<>();
+    private List<ConnectionWrapper> usedPool = new LinkedList<>();
+
     private int minimumNumberOfConnections = 0;
     private int maximumNumberOfConnections = 20;
-    private int used = 0;
 
     public ConnectionPool() {
     }
@@ -46,10 +47,10 @@
     }
 
     public synchronized Connection getConnection() {
-        if (connectionPool.isEmpty() && used < maximumNumberOfConnections) {
+        if (connectionPool.isEmpty() && usedPool.size() < maximumNumberOfConnections) {
             ConnectionWrapper wrapper = new ConnectionWrapper(this, connectionProvider.getConnection());
 
-            used++;
+            usedPool.add(wrapper);
             return wrapper;
         }
 
@@ -62,14 +63,20 @@
             }
         }
 
-        used++;
-        return connectionPool.remove(0);
+        ConnectionWrapper result = connectionPool.remove(0);
+        usedPool.add(result);
+        return result;
     }
 
     protected synchronized void returnConnection(ConnectionWrapper connection) {
-        used--;
-        connectionPool.add(connection);
-        notify();
+        if (usedPool.contains(connection)) {
+            usedPool.remove(connection);
+            connectionPool.add(connection);
+            notify();
+        } else {
+            // discard (clear was probably called)
+            connection.dispose();
+        }
     }
 
     public boolean hasConnectionProvider() {
@@ -77,6 +84,11 @@
     }
 
     public synchronized void clear() {
-        connectionPool = new LinkedList<>();
+        connectionPool.clear();
+        usedPool.clear();
+    }
+
+    public ConnectionProvider getProvider() {
+        return connectionProvider;
     }
 }
diff --git a/test/nl/astraeus/database/TestFind.java b/test/nl/astraeus/database/TestFind.java
index 0336df7..d90afc7 100644
--- a/test/nl/astraeus/database/TestFind.java
+++ b/test/nl/astraeus/database/TestFind.java
@@ -39,6 +39,8 @@
                 }
             }
         });
+
+        ConnectionPool.get().clear();
     }
 
     @AfterClass
@@ -61,10 +63,10 @@
 
         Person p2 = Persister.find(Person.class, id);
 
-        Persister.rollback();
-
         Assert.assertNotNull(p2);
         Assert.assertEquals("Rien", p2.getName());
+
+        Persister.rollback();
     }
 
 }

diff --git a/src/nl/astraeus/database/ObjectPersister.java b/src/nl/astraeus/database/ObjectPersister.java
index c3fd8b4..ec2eec6 100644
--- a/src/nl/astraeus/database/ObjectPersister.java
+++ b/src/nl/astraeus/database/ObjectPersister.java
@@ -20,6 +20,9 @@
 
     public void insert(Object object) {
         metaData.insert(object);
+
+        Long id = metaData.getId(object);
+        Cache.get().set((Class<Object>) object.getClass(), id, object);
     }
 
     public void update(Object object) {
diff --git a/src/nl/astraeus/database/jdbc/ConnectionPool.java b/src/nl/astraeus/database/jdbc/ConnectionPool.java
index 5265dc4..ca163a6 100644
--- a/src/nl/astraeus/database/jdbc/ConnectionPool.java
+++ b/src/nl/astraeus/database/jdbc/ConnectionPool.java
@@ -23,9 +23,10 @@
     private ConnectionProvider connectionProvider = null;
 
     private List<ConnectionWrapper> connectionPool = new LinkedList<>();
+    private List<ConnectionWrapper> usedPool = new LinkedList<>();
+
     private int minimumNumberOfConnections = 0;
     private int maximumNumberOfConnections = 20;
-    private int used = 0;
 
     public ConnectionPool() {
     }
@@ -46,10 +47,10 @@
     }
 
     public synchronized Connection getConnection() {
-        if (connectionPool.isEmpty() && used < maximumNumberOfConnections) {
+        if (connectionPool.isEmpty() && usedPool.size() < maximumNumberOfConnections) {
             ConnectionWrapper wrapper = new ConnectionWrapper(this, connectionProvider.getConnection());
 
-            used++;
+            usedPool.add(wrapper);
             return wrapper;
         }
 
@@ -62,14 +63,20 @@
             }
         }
 
-        used++;
-        return connectionPool.remove(0);
+        ConnectionWrapper result = connectionPool.remove(0);
+        usedPool.add(result);
+        return result;
     }
 
     protected synchronized void returnConnection(ConnectionWrapper connection) {
-        used--;
-        connectionPool.add(connection);
-        notify();
+        if (usedPool.contains(connection)) {
+            usedPool.remove(connection);
+            connectionPool.add(connection);
+            notify();
+        } else {
+            // discard (clear was probably called)
+            connection.dispose();
+        }
     }
 
     public boolean hasConnectionProvider() {
@@ -77,6 +84,11 @@
     }
 
     public synchronized void clear() {
-        connectionPool = new LinkedList<>();
+        connectionPool.clear();
+        usedPool.clear();
+    }
+
+    public ConnectionProvider getProvider() {
+        return connectionProvider;
     }
 }
diff --git a/test/nl/astraeus/database/TestFind.java b/test/nl/astraeus/database/TestFind.java
index 0336df7..d90afc7 100644
--- a/test/nl/astraeus/database/TestFind.java
+++ b/test/nl/astraeus/database/TestFind.java
@@ -39,6 +39,8 @@
                 }
             }
         });
+
+        ConnectionPool.get().clear();
     }
 
     @AfterClass
@@ -61,10 +63,10 @@
 
         Person p2 = Persister.find(Person.class, id);
 
-        Persister.rollback();
-
         Assert.assertNotNull(p2);
         Assert.assertEquals("Rien", p2.getName());
+
+        Persister.rollback();
     }
 
 }
diff --git a/test/nl/astraeus/database/TestMissingReference.java b/test/nl/astraeus/database/TestMissingReference.java
index d9c2632..ff57614 100644
--- a/test/nl/astraeus/database/TestMissingReference.java
+++ b/test/nl/astraeus/database/TestMissingReference.java
@@ -40,6 +40,8 @@
                 }
             }
         });
+
+        ConnectionPool.get().clear();
     }
 
     @AfterClass