Feeding a created subprocess with data in Java

Question

I started to learn about processes in Java, so following question popped up. Let's say that I have some text data stored in variable. I want to start notepad.exe by starting a new process and somehow to pass this text data to it, so it can be shown. Here is some basic snippet that I found. How can I change it, so it performs feeding of notepad with text stored in variable ? Also, can I make generalization and assume that I have some .pdf file completely loaded in RAM. Can I start new process in which I will invoke some PDF reader and feed it with .pdf data stored in RAM? Thanks!

p.s. I don't want to store data into file (or cache) and then perform feeding of application from it.

   try {
        // create a new process
        System.out.println("Creating Process...");
        Process p = Runtime.getRuntime().exec("notepad.exe");

        // get the output stream
        OutputStream out = p.getOutputStream();

        // close the output stream
        System.out.println("Closing the output stream...");
        out.close();
  } catch (Exception ex) {
        ex.printStackTrace();
  }