Issues in getting the output when calling a python script from Java

Question

I've a Java program to call a python script. I've used exec method. Please find the code snippet below:

Python program (which is to gather a portion of text from wikipedia), when run separately, gives me proper output. When called from Java, I'm not getting the complete output from python program.

I checked the status of BufferedReader Object using ready() method ( as explained here, and the code entered into infinite loop.

I think others also have faced similar problems-https://stackoverflow.com/a/20661352/3409074

Can anyone help me?

      public String enhanceData(String name,String entity) {
            String s = null;
            StringBuffer output = new StringBuffer();
            try{
                String command="python C://enhancer.py "+name+" "+entity;
                Process p = Runtime.getRuntime().exec(command);
                BufferedReader stdError=new BufferedReader(new InputStreamReader(p.getErrorStream()));
                BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
                while ((s = stdInput.readLine()) != null) {

                    System.out.println(s);
                    output.append(s);
                  }

Answer 1

The while loop condition has actually already read a line so you are double reading it for every time in the loop.

while ((s = stdInput.readLine()) != null) {
    //s=stdInput.readLine();  <- don't need this
    System.out.println(s);
    output.append(s);
}

/Nick