diff --git a/lib/activeadmin/resource_dsl.rb b/lib/activeadmin/resource_dsl.rb
index 551cc77..746886a 100644
--- a/lib/activeadmin/resource_dsl.rb
+++ b/lib/activeadmin/resource_dsl.rb
@@ -18,9 +18,10 @@ def json_editor
         object.nested_attributes_options.keys.each {|_nested_key|
           nested_attributes_with_index = params[resource_request_name]["#{_nested_key}_attributes"]
           next if nested_attributes_with_index.nil?
-          nested_klass = _nested_key.to_s.singularize.camelize.constantize
+          nested_klass = object.class.reflect_on_association(_nested_key).class_name.constantize
           nested_klass.columns_hash.select { |_key, attr| attr.type.in? [:json, :jsonb] }.keys.each do |key|
             nested_attributes_with_index.each {|_index, nested_attributes|
+              next unless nested_attributes.respond_to?(:key)
               next unless nested_attributes.key? key
               json_data = nested_attributes[key]
               data = if json_data == 'null' || json_data.blank?