diff --git a/src/main/java/com/noorq/casser/core/SessionInitializer.java b/src/main/java/com/noorq/casser/core/SessionInitializer.java
index fab1047..d41b70a 100644
--- a/src/main/java/com/noorq/casser/core/SessionInitializer.java
+++ b/src/main/java/com/noorq/casser/core/SessionInitializer.java
@@ -139,7 +139,10 @@ public final class SessionInitializer extends AbstractSessionOperations {
 	
 	public SessionInitializer addPackage(String packageName) {
 		try {
-			PackageUtil.getClasses(packageName).forEach(initList::add);
+			PackageUtil.getClasses(packageName)
+				.stream()
+				.filter(c -> c.isInterface())
+				.forEach(initList::add);
 		} catch (ClassNotFoundException e) {
 			throw new CasserException("fail to add package " + packageName, e);
 		}
diff --git a/src/test/java/com/noorq/casser/test/integration/core/simple/StaticColumnTest.java b/src/test/java/com/noorq/casser/test/integration/core/simple/StaticColumnTest.java
index 763987f..5c3322f 100644
--- a/src/test/java/com/noorq/casser/test/integration/core/simple/StaticColumnTest.java
+++ b/src/test/java/com/noorq/casser/test/integration/core/simple/StaticColumnTest.java
@@ -34,7 +34,7 @@ public class StaticColumnTest extends AbstractEmbeddedCassandraTest {
 	
 	@BeforeClass
 	public static void beforeTest() {
-		Casser.init(getSession()).showCql().add(Message.class).autoCreateDrop().singleton();
+		Casser.init(getSession()).showCql().addPackage(Message.class.getPackage().getName()).autoCreateDrop().singleton();
 	}
 	
 	@Test