It sounds like you may be confused about Jackson usage here. If you have a String that contains JSON, do not use Jackson for writing it out -- all Jackson knows is that it is a String, and Strings in JSON must be enclosed in double-quotes, and have their contents escaped.
If you do not want this, simply output String as-is, and do not use Jackson for output.

But if you have such a String property as part of your object model, you can use annotation @JsonRawValue to embed it as-is, without escaping. This may be what you are looking for.

I hope this helps.

I have converted the json String to JsonNode before passing it back from the below method (after Jackson upgrade to 2.2).

But - this used to work in 1.9 version of jackson (example below) and since my upgrade to 2.2 its broken and the way I fixed it is by wrapping the JSON string from another rest call in JsonNode.

@Path("/health")
@GET
@Produces(MediaType.APPLICATION_JSON)
public String getHealth(@QueryParam("app_id") String app_id) {
    URIBuilder uriBuilder = new URIBuilder(sparkpayUrl + "/ping");
    uriBuilder.addParameter("app_id", app_id);
    String url = URLDecoder.decode(uriBuilder.toString(), "UTF-8");
    logger.debug("Sparkpay Health Check url : ", url);
    String status  = restTemplate.getForObject(url, String.class);
    logger.debug("Sparkpay Health status : ", status);
    return status;
}

Could you not just return JsonNode or POJO, and let JAX-RS do its job? Is there need to produce a String at this point.

Question is whether JAX-RS MessageBodyWriter should write String as "raw" String, or as JSON String. I don't know what the right answer is: both have their merits. But I thought that 2.2.3 should write it as raw String, not JSON String.

That is what I'm returning right now - I changed the signature of the call to be

public JsonNode getHealth(@QueryParam("app_id") String app_id) {
....
...
JsonNode status = restTemplate.getForObject(url, JsonNode.class);
return status;
}

This rest service is nothing but a wrapper to another internal rest service with key management/security. This is just an example of ping we have many more operations in this API.

All I wanted was return back the json string from the rest call - I don't want to create unnecessary POJO's. As I mentioned earlier - it worked perfectly well in 1.9 but in 2.2 I had to wrap the json string with JsonNode and return it back or else jackson adds quotes to json string.

This should not be the case, unless you are using version 2.0.0 of Jackson's JSON provider, which did have issue:

https://github.com/FasterXML/jackson-jaxrs-json-provider/issues/12

JAX-RS provider should consider String to be raw type ("untouchable"), write it exactly as-is. So I don't know what the problem could be here; unless it was a version mismatch of some sort.
Similarly other raw types (like byte[]) should be passed as-is.

One more thing to verify, just to rule out version issues: 2.3.0-rc1 is out (and official 2.3.0 in a week or two if all goes well), so would it be possible to try that version? It should be backwards compatible at API level so relatively easy to swap in.

I tried the latest version of jackson and I have the same issue when using String:

"{\n "status" : "Success",\n "pong" : 1\n}"

Maven Dependency Tree info :

[INFO] +- com.fasterxml.jackson.core:jackson-annotations:jar:2.3.0-rc1:compile
[INFO] +- com.fasterxml.jackson.core:jackson-core:jar:2.3.0-rc1:compile
[INFO] +- com.fasterxml.jackson.core:jackson-databind:jar:2.3.0-rc1:compile
[INFO] +- com.fasterxml.jackson.module:jackson-module-jaxb-annotations:jar:2.3.0-rc1:compile

If I change the api to return JsonNode, I get what I expect:

{"status":"Success","pong":1}

Ok. That sounds like a bug then. I will need to move this, however, as it is in JAX-RS module.

I am unfortunately unable to reproduce this, see the new issue.

I'm experiencing this using JSONPObject. I want to pass a raw json as String but Jackson Provider escapes my String. Is there some way to tell Jackson Provider to not parse JSONPObject content?

No; JSONPObject functionally only works for output.

It might make sense to add a new annotation to indicate "do not parse" for JAX-RS module. If so, it'd be necessary to file an issue for jackson-jaxrs-providers project.

The reason for adding a new annotation (instead of trying to reuse something that would seem useful like @JsonRawValue) is simply because JAX-RS does not give enough context to reliably know target of annotations, at least for some cases: specifically, method annotations could be viewed to have effect on return value and/or parameters.