Interaction between Java App and Python App

Question

I have a python application which I cant edit its a black box from my point of view. The python application knows how to process text and return processed text. I have anoth

Answer 1

I don't know nothing about Jython and the like. I guess it's the best solution if you can execute two programs without executing a new process each time the Java app needs to transform text. Anyway a simple proof of concept is to execute a separate process from the Java App to make it work. Next you can enhance the execution with all that tools.

Executing a separate process from Java

String[] envprops = new String[] {"PROP1=VAL1", "PROP2=VAL2" };
Process pythonProc = Runtime.getRuntime().exec(
   "the command to execute the python app", 
    envprops, 
    new File("/workingdirectory"));

// get an outputstream to write into the standard input of python
OutputStream toPython = pythonProc.getOutputStream();

// get an inputstream to read from the standard output of python
InputStream fromPython = pythonProc.getInputStream();

// send something
toPython.write(.....);
// receive something
fromPython.read(....);

Important: chars are NOT bytes

A lot of people understimate this.

Be careful with char to byte conversions (remember Writers/Readers are for chars, Input/OutputStreams are for bytes, encoding is necesary for convertir one to another, you can use OuputStreamWriter to convert string to bytes and send, InputStreamReader to convert bytes to chars and read them).