title: Java: OutputStream to .exe Console App issue
body: <p>I am trying to interact with a simple .exe I created from some Python code. I have tested the .exe through Windows cmd and it works just fine. When I try to send the same input to the .exe through my java program to produce the graphs I need, OutputStream just writes "error" to the console. I have tried sending a string and an integer through OutputStream but the same results are obtained no matter what. I have already interacted with X-Foil.exe, a console application use to produce airfoil data files, with great success through this same java app. As I have to preform curve fitting to the data, I used Python with the matplotlib plugin then used py2exe to create the .exe. I am trying to create a web application with the end goal of designing an aircraft wing, hence the use of java. Here is the method being use which I am having the problem with:</p>
  
  <pre><code>    public void PyGrapher(String NACA_4d) {
      try {
          ProcessBuilder builder = new ProcessBuilder("PyAirfoilGraphing\\dist\\GraphPolars.exe");
          builder.redirectErrorStream(true);
          Process pr = builder.start();
          OutputStream out = pr.getOutputStream();
          BufferedReader in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
  
          double CL_alpha;
  
          out.write((NACA_4d + "\n").getBytes());
  
          System.out.println(in.readLine());
          System.out.println(in.readLine());
          System.out.println(in.readLine());
          System.out.println(in.readLine());
          //CL_alpha = Double.parseDouble(in.readLine());
  
          pr.waitFor();
          pr.destroy();
          out.close();
          in.close();
  
      } catch (IOException | InterruptedException ex) {
      }
  }
  </code></pre>
  
  <p>Here is what I have read in from the console:</p>
  
  <pre><code>  Input NACA 4-digit code: error
    Traceback (most recent call last):
      File "GraphPolars.py", line 16, in &lt;module&gt;
    IOError: [Errno 2] No such file or directory: '..\\..\\AirfoilPolars\\NACA_0024.dat'
  </code></pre>
  
  <p>I am stumped, and have been for quite some time. There is not a problem with the python file,  and it runs fine by itself in the current directory. Can anyone help, please?</p>
  
  <p>-Nick K</p>