[API_13] RundeckClient builder not working with sessionId

[rmartev]

After I have obtained the value of the JSESSIONID cookie (I've logged in using the plain API, not the java client), I'm trying to create a RundeckClienti with which I could run the other requests to the Rundeck server. Here is a snippet of my code:

RundeckClientBuilder clientBuilder = RundeckClient.builder();
clientBuilder.url(rundeckServerUrl);
clientBuilder.sessionId(jsessionid);
rundeckClient = clientBuilder.build();

where "jsessionid" is the value of the cookie, that I took from the password authentication (it is NOT null). The execution of this snippet throws the following exception:

java.lang.IllegalArgumentException: sessionId cannot be blank
at org.rundeck.api.util.AssertUtil.notBlank(AssertUtil.java:49)
at org.rundeck.api.RundeckClientBuilder.build(RundeckClientBuilder.java:94)

Am I missusing the API? Please, help.