diff --git a/src/main/java/com/mysema/codegen/CodeWriter.java b/src/main/java/com/mysema/codegen/CodeWriter.java
index d8a4e8b27..0ff75bd6a 100644
--- a/src/main/java/com/mysema/codegen/CodeWriter.java
+++ b/src/main/java/com/mysema/codegen/CodeWriter.java
@@ -9,6 +9,8 @@ import java.io.IOException;
 import java.lang.annotation.Annotation;
 import java.util.Collection;
 
+import javax.annotation.Nullable;
+
 import org.apache.commons.collections15.Transformer;
 
 /**
@@ -25,7 +27,7 @@ public interface CodeWriter extends Appendable{
 
     CodeWriter beginClass(String simpleName) throws IOException;
 
-    CodeWriter beginClass(String simpleName, String superClass, String... interfaces) throws IOException;
+    CodeWriter beginClass(String simpleName, @Nullable String superClass, String... interfaces) throws IOException;
 
     <T> CodeWriter beginConstructor(Collection<T> params, Transformer<T, String> transformer) throws IOException;
 
diff --git a/src/main/java/com/mysema/codegen/model/ClassType.java b/src/main/java/com/mysema/codegen/model/ClassType.java
index 037b89664..8a8cf2e14 100644
--- a/src/main/java/com/mysema/codegen/model/ClassType.java
+++ b/src/main/java/com/mysema/codegen/model/ClassType.java
@@ -11,6 +11,8 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 
+import javax.annotation.Nullable;
+
 import com.mysema.codegen.support.ClassUtils;
 
 /**
@@ -26,13 +28,14 @@ public class ClassType<T> implements Type {
     
     private final List<Type> parameters;
     
+    @Nullable
     private final Class<?> primitiveClass;
     
-    public ClassType(TypeCategory category, Class<T> javaClass, Class<?> primitiveClass) {
+    public ClassType(TypeCategory category, Class<T> javaClass, @Nullable Class<?> primitiveClass) {
         this(category, javaClass, primitiveClass, Collections.<Type>emptyList());
     }
         
-    public ClassType(TypeCategory category, Class<T> javaClass, Class<?> primitiveClass, List<Type> parameters) {
+    public ClassType(TypeCategory category, Class<T> javaClass, @Nullable Class<?> primitiveClass, List<Type> parameters) {
         this.category = category;
         this.javaClass = javaClass;
         this.primitiveClass = primitiveClass;
diff --git a/src/main/java/com/mysema/codegen/model/Type.java b/src/main/java/com/mysema/codegen/model/Type.java
index 0ca4f37b5..e0888be9c 100644
--- a/src/main/java/com/mysema/codegen/model/Type.java
+++ b/src/main/java/com/mysema/codegen/model/Type.java
@@ -8,6 +8,8 @@ package com.mysema.codegen.model;
 import java.util.List;
 import java.util.Set;
 
+import javax.annotation.Nullable;
+
 /**
  * @author tiwe
  *
@@ -31,6 +33,7 @@ public interface Type {
 
     List<Type> getParameters();
     
+    @Nullable
     String getPrimitiveName();
     
     String getRawName(Set<String> packages, Set<String> classes);
diff --git a/src/main/java/com/mysema/codegen/model/TypeCategory.java b/src/main/java/com/mysema/codegen/model/TypeCategory.java
index 720bb0630..07b676f0c 100644
--- a/src/main/java/com/mysema/codegen/model/TypeCategory.java
+++ b/src/main/java/com/mysema/codegen/model/TypeCategory.java
@@ -8,6 +8,8 @@ package com.mysema.codegen.model;
 import java.util.HashSet;
 import java.util.Set;
 
+import javax.annotation.Nullable;
+
 /**
  * TypeCategory defines the expression type used for a Field
  *
@@ -85,11 +87,12 @@ public enum TypeCategory {
      */
     TIME(COMPARABLE, java.sql.Time.class.getName(), "org.joda.time.LocalTime");
 
+    @Nullable
     private final TypeCategory superType;
 
     private final Set<String> types;
 
-    TypeCategory(TypeCategory superType, String... types){
+    TypeCategory(@Nullable TypeCategory superType, String... types){
         this.superType = superType;
         this.types = new HashSet<String>(types.length);
         for (String type : types){