we have a mobile app->apache->tomcat stack we are monitoring with Dynatrace, and we would like to extract (for example) the result of a login call (I'm talking of the applicative result, so it's a field in the response, not the HTTP code).
Do you confirm that Dynatrace can't extract the result from an HTTP response?
The only way of doing this, if I'm correct, is to intercept the calls to the Java methods and try to extract a return value (via Settings->Server-side service monitoring->Request attributes). Is this correct?
You can indeed extract portions of the response body by defining request attributes with the data source being, in this case, Java method parameters. You probably need to work with the developers a bit, to figure out which class and method outputs the data which you want to extract.
In general dynatrace does not allow for capturing the payload of an HTTP calls. The only exception is HTTP POST parameters of a request.
But you most certainly can get the data you need via a Java method parameter(s) Request Attribute, you just have to find the correct class/method to capture the argument you want.