wait for method of process class doesn't return

Question

I have Process Class in my code and that couldn't read the inputbufferreader data when i try to reading the larger number of data from inputbuffer and waitfor method of process class never return anything

• this issue is happened in live server

• but below code running fine and read the all the data from inputbuffer in local server

  private static JSONObject ExecJniApp(String inputJsonString) throws JniException
  {
  int exitStatus = 0;
  String workingDirectory = JniSettings.getJniAppDirectory();
  String command = workingDirectory + binaryName;
  System.out.println("ExecJniApp: inputJsonString: " + inputJsonString);
  String outputString = "";
  try
  {
      Process p = Runtime.getRuntime().exec(command, null, new File(workingDirectory));
      // send input vi stdin
      BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(p.getOutputStream()));
      writer.write("\n>>>>>>>>>>");
      writer.write(inputJsonString);
      writer.write("<<<<<<<<<<\n");
      writer.flush();
      if (JniSettings.isLinux())
      {
          p.waitFor();
      }
      else
      {
          // System.out.println("ExecJniApp: windows wait for");
      }
      BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
      for (;;)
      {
          String line = reader.readLine();
          if (line == null)
          {
              break;
          }
          // System.out.println(line);
          outputString += line + "\n";
      }
      // exit code of command and log error detail
      // exit status = 0 -> Success
      exitStatus = p.exitValue();
      if (exitStatus != 0)
      {
          System.out.println("ExecJniApp: inputJsonString: " + inputJsonString);
          System.out.println("ExecJniApp: outputString:\n" + outputString);
          throw new Exception("Exit status other than zero :- " + exitStatus + "\noutput: ");
      }
  }
  catch (Exception e)
  {
      // System.out.println("ExecJniApp failed");
      e.printStackTrace();
      throw new JniException("JniInterface failed");
  }
  System.out.println("ExecJniApp: outputString:\n" + outputString);
  int index1 = outputString.indexOf(">>>>>>>>>>");
  if (index1 == -1)
  {
      // System.out.println("ExecJniApp failed, Invalid output format");
      throw new JniException("ExecJniApp failed, Invalid output format");
  }
  index1 += 10;
  int index2 = outputString.indexOf("<<<<<<<<<<");
  if (index2 == -1 || index2 <= index1)
  {
      // System.out.println("ExecJniApp failed, Invalid output format");
      throw new JniException("ExecJniApp failed, Invalid output format");
  }
  String outputJsonString = outputString.substring(index1, index2);
  // System.out.println("ExecJniApp: outputJsonString: " + outputJsonString);
  JSONParser parser = new JSONParser();
  JSONObject obj = null;
  try
  {
      obj = (JSONObject) parser.parse(outputJsonString);
  }
  catch (ParseException e)
  {
      // System.out.println("ExecJniApp failed, Json parse failed");
      e.printStackTrace();
      throw new JniException("JniInterface failed, Json parse failed");
  }
  Object errorObject = obj.get("error");
  if (errorObject != null)
  {
      String errorString = errorObject.toString();
      // System.out.println("ExecJniApp failed, " + errorString);
      throw new JniException("ExecJniApp failed, " + errorString);
  }
  return obj;
  }
  

Answer 1

Just replace your code with below code.
Must close your InputStream connection.

 Process p = Runtime.getRuntime().exec(command, null, new File(workingDirectory));
// send input vi stdin
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(p.getOutputStream()));
writer.write("\n>>>>>>>>>>");
writer.write(inputJsonString);
writer.write("<<<<<<<<<<\n");
writer.flush();

try{ 
BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
for (;;)
{
    String line = reader.readLine();
    if (line == null)
    {
        break;
    }
    // System.out.println(line);
    outputString += line + "\n";
}
 p.getOutputStream().close();
 p.getInputStream().close();
}
catch(Exception e)
{
   e.printStackTrace();
}
if (JniSettings.isLinux())
{
    p.waitFor();
}
else
{
    // System.out.println("ExecJniApp: windows wait for");
}
// exit code of command and log error detail
// exit status = 0 -> Success
exitStatus = p.exitValue();
if (exitStatus != 0)
{
    System.out.println("ExecJniApp: inputJsonString: " + inputJsonString);
    System.out.println("ExecJniApp: outputString:\n" + outputString);
    throw new Exception("Exit status other than zero :- " + exitStatus + "\noutput: ");
}