diff --git a/src/main/java/com/mysema/query/QueryBase.java b/src/main/java/com/mysema/query/QueryBase.java
index 433572c02..d67ce67c5 100644
--- a/src/main/java/com/mysema/query/QueryBase.java
+++ b/src/main/java/com/mysema/query/QueryBase.java
@@ -25,7 +25,7 @@ public class QueryBase<A extends QueryBase<A>> implements Query<A> {
         DEFAULT,IJ,LJ,J
     }
     
-    public class JoinExpression{
+    public static class JoinExpression{
         public final JoinType type;
         public final ExprEntity<?> target;
         JoinExpression(JoinType type, ExprEntity<?> target){
@@ -36,10 +36,10 @@ public class QueryBase<A extends QueryBase<A>> implements Query<A> {
     }
     
     protected final List<JoinExpression> joins = new ArrayList<JoinExpression>();
-    protected final List<Expr> groupBy = new ArrayList<Expr>();
+    protected final List<Expr<?>> groupBy = new ArrayList<Expr<?>>();
     protected final List<ExprBoolean> having = new ArrayList<ExprBoolean>();
-    protected final List<OrderSpecifier> orderBy = new ArrayList<OrderSpecifier>();
-    protected final List<Expr> select = new ArrayList<Expr>();
+    protected final List<OrderSpecifier<?>> orderBy = new ArrayList<OrderSpecifier<?>>();
+    protected final List<Expr<?>> select = new ArrayList<Expr<?>>();
     protected final List<ExprBoolean> where = new ArrayList<ExprBoolean>();
     
     protected void clear(){
@@ -50,7 +50,7 @@ public class QueryBase<A extends QueryBase<A>> implements Query<A> {
         select.clear();
         where.clear();
     }
-    
+        
     public A from(ExprEntity<?>... o) {
         for (ExprEntity<?> expr : o){
             joins.add(new JoinExpression(JoinType.DEFAULT,expr));
diff --git a/src/main/java/com/mysema/query/grammar/Types.java b/src/main/java/com/mysema/query/grammar/Types.java
index eae36c0fe..36936dba8 100644
--- a/src/main/java/com/mysema/query/grammar/Types.java
+++ b/src/main/java/com/mysema/query/grammar/Types.java
@@ -90,6 +90,10 @@ public class Types {
         ExprBoolean lt(Expr<D> right);
     }
     
+    public interface ExprString extends ExprComparable<String>{
+        
+    }
+    
     
     /**
      * Reference to an entity
@@ -133,8 +137,7 @@ public class Types {
         implements ExprBoolean {    
         public ExprBoolean and(ExprBoolean right) {return Grammar.and(this, right);}
         public ExprBoolean or(ExprBoolean right) {return Grammar.or(this, right);}
-    }
-    
+    }    
     
     public enum Order{ ASC,DESC }
         
@@ -202,7 +205,6 @@ public class Types {
     public static class PathEntityCollection<D> extends Path<Collection<D>> implements 
         ExprEntity<Collection<D>>{
         PathEntityCollection(Class<D> type, String p) {
-            // FIXME
             super(null, p);
         }        
         public AliasCollection<D> as(PathEntity<D> to) {
@@ -219,7 +221,7 @@ public class Types {
         }        
     }
     
-    public static class PathString extends PathComparable<String>{
+    public static class PathString extends PathComparable<String> implements ExprString{
         public PathString(String p) {
             super(String.class, p);
         }