google cloud endpoints returning java long as string in JSON

[Naresh Pokuri]

I am using google app engine latest version 1.9.30 and I define my cloud endpoint as follows

@Api(name="app", version="v1", transformers={EndpointDateTransformer.class})
public class MyEndpoints {

    @ApiMethod(name="dummy", path="dummy", httpMethod=HttpMethod.GET)
    public Map<String, Object> dummy(){
        Map<String, Object> dummy = Maps.newHashMap();
        dummy.put("date", DateUtil.getCurrentTimestamp());
        dummy.put("number", 5L);
        return dummy;
    }

}

here EndpointDateTransformer converts Date to Long value and the JSON response from endpoint is

{
    "number": "5",
    "date": "1452751174672"
}
But if I change that 5L to 5 then I see JSON response as
{
    "number": 5,
    "date": "1452751174672"
}
Why cloud endpoints converting Long values as string in JSON. When I was working on old app engine versions 1.9.19 it used to work. Long rendered as long on JSON as well. Am I missing anything here?

[Nick (Cloud Platform Support)]

This seems to be intended behaviour for Long values since they can actually exceed the max size of a Javascript number. Longs, according to the docs, can go to 2⁶³-1, while Javascript can only represent integers safely up to about 2⁵³. If you don't think you'll need numbers above 2⁵³, you could downgrade the "number" property to java int and still be safe.