Pass env variables to junit test from jenkins

[Serega Sheypak]

Hi, I have pretty silly question. Please help me.
I do have a test which gets parameters from env variables:

public Conf(){
        this.hostname = System.getProperty(WEBAPP_HOST);
        this.port =   System.getProperty(WEBAPP_PORT);
        this.contextPath = System.getProperty(WEBAPP_CONTEXTPATH);
        this.scoringServletname = 
System.getProperty(WEBAPP_SCORING_SERVLETNAME);

    }
I do pass these variables in this way:
mvn test -DargLine="-Dwebapp.port=12345 -Dwebapp.host=xxx.yyy.net 
-Dwebapp.contextpath=my-webapp -Dwebapp.my.servletname=myServlet"

How can I do the same using jenkins?
I've tried a lot of stuff, but nothing helps. Conf ogject gets null values 
during instantiation.