How to add simple path in exec command??

Question

Hello friends...want some help on "How to add simple path in exec command?"Because on linux each time username changes I will have to change username in exec command.Please help me.
My code for java on linux is
Runtime r4=Runtime.getRuntime();
                                   Process p4=null;
     //     "oofromtemplate" is command name for openoffice on linux                    //my username on linux is "sandy"     
                                   try
                                   p4=r4.exec("oofromtemplate /home/sandy/complete/Output.html");
                                   catch(Exception ae)
                                   System.out.println("error");
                                   }

Answer 1

System properties yield among other things:
user.name       User's account name
user.home      User's home directory
user.dir      User's current working directory