[java] fixed issue #1161

genjava.ml

@@ -578,6 +578,19 @@ struct
             | _ -> true
           in
           if need_second_cast then { e with eexpr = TCast(mk_cast (follow e.etype) (run expr), c) }  else Type.map_expr run e*)
+        | TBinop( (Ast.OpAssignOp OpAdd as op), e1, e2)
+        | TBinop( (Ast.OpAdd as op), e1, e2) when is_string e.etype || is_string e1.etype || is_string e2.etype ->
+            let is_assign = match op with Ast.OpAssignOp _ -> true | _ -> false in
+            let mk_to_string e = { e with eexpr = TCall( mk_static_field_access_infer runtime_cl "toString" e.epos [], [run e] ); etype = gen.gcon.basic.tstring  } in
+            let check_cast e = match gen.greal_type e.etype with
+              | TDynamic _
+              | TAbstract({ a_path = ([], "Float") }, [])
+              | TAbstract({ a_path = ([], "Single") }, []) ->
+                  mk_to_string e
+              | _ -> run e
+            in
+
+            { e with eexpr = TBinop(op, (if is_assign then run e1 else check_cast e1), check_cast e2) }
         | TCast(expr, _) when is_string e.etype ->
           { e with eexpr = TCall( mk_static_field_access_infer runtime_cl "toString" expr.epos [], [run expr] ) }
 
@@ -1951,7 +1964,7 @@ let configure gen =
     { ecall with eexpr = TCall(efield, elist) }
   );
 
-  CastDetect.configure gen (CastDetect.default_implementation gen (Some (TEnum(empty_e, []))) true);
+  CastDetect.configure gen (CastDetect.default_implementation gen ~native_string_cast:false (Some (TEnum(empty_e, []))) true);
 
   (*FollowAll.configure gen;*)