Pokuri Pokuri - 3 months ago 23x
JSON Question

google cloud endpoints returning java long as string in JSON

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?


JSON is JavaScript Object Notation, it's a valid Javascript actually. So it should follow javascript standards.

Javascript's Number is 54 bit number, from -(2^53 - 1) to (2^53 - 1). But Java's long is 64 bit number, from -2^63 to 2^63-1.

See difference:

Java Long Max         = 9223372036854775807
Javascript Number Max = 9007199254740992

You simply cannot convert Java Long to Javascript Number because it doesn't work for all values. So a string representation is used instead.

You have two possible solutions: