Opening files with .jnlp extension on browser!?!?!

I working on UEngine, where to switch into the design phase it creates a PorcessDesigner.jnlp file which gets downloaded on client's side on runtime. I searched into the code for

Runtime.getRuntime().exec("...........");

I came across the java code where is has been used. I dont want this file to be downloaded into the client's pc. Rather i want to open it in my browser(Mozilla/IE) itself. Kindly provide me with the reference/steps to resolve the issue.Thanks