add an option to hide system attributes (e.g. the class name) in the json

Box has a list of Product
public class Box {

private Integer id;

private String name;

private List<Product> products = new ArrayList<Product>();

// getters and setters
}

I serialize the box instance to json, the result is
{"box":{"id":"1","name":"box1","products":{"product":[

{"id":"1","name":"product1","price":"11.0"}

,

{"id":"3","name":"product3","price":"33.0"}

]
}}}

but what I want is( without alias of class name: "box" , "product")
{"id":"1","name":"box1", "products": [

{"id":"1","name":"product1","price":"11.0"}

,

{"id":"3","name":"product3","price":"33.0"}

]
}

The tree of Ext requires the latter form

So if possible, please provide a option to hide the class names, thanks