[JOHNZON-332] add skipAccessModeWrapper toggle for backward compatibility
diff --git a/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/MapperBuilder.java b/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/MapperBuilder.java
index cbb2213..9646a90 100644
--- a/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/MapperBuilder.java
+++ b/johnzon-mapper/src/main/java/org/apache/johnzon/mapper/MapperBuilder.java
@@ -106,6 +106,7 @@
     private boolean useBigDecimalForObjectNumbers;
     private boolean supportEnumContainerDeserialization = true;
     private Function<Class<?>, MapperConfig.CustomEnumConverter<?>> enumConverterFactory = type -> new EnumConverter(type);
+    private boolean skipAccessModeWrapper;
 
     // @experimental polymorphic api
     private Function<String, Class<?>> typeLoader;
@@ -200,7 +201,7 @@
                 throw new IllegalStateException("AccessMode is not an BaseAccessMode");
             }
         }
-        if (!KnownNotOpenedJavaTypesAccessMode.class.isInstance(accessMode)) {
+        if (!skipAccessModeWrapper && !KnownNotOpenedJavaTypesAccessMode.class.isInstance(accessMode)) {
             accessMode = new KnownNotOpenedJavaTypesAccessMode(accessMode);
         }
 
@@ -561,4 +562,9 @@
         this.discriminator = value;
         return this;
     }
+
+    public MapperBuilder setSkipAccessModeWrapper(final boolean skipAccessModeWrapper) {
+        this.skipAccessModeWrapper = skipAccessModeWrapper;
+        return this;
+    }
 }