Runtime Exec output

Question

I want to execute a class method that is present in another file. I am doing the following:

import java.io.IOException;
public class run_java_program {
 public static void main(String[] args) {
 try {
 Process process = Runtime.getRuntime().exec("java -cp C:\\Users\96171円\\eclipse-workspace\\IR_Project\\src test");
 } catch (IOException e) { 
 e.printStackTrace(); 
 } 
 }
}

But its not working. However on the cmd it is:

enter image description here

I tried replacing C:\\Users\96171円\\eclipse-workspace\\IR_Project\\src with C:/Users/96171/eclipse-workspace/IR_Project/src but still nothing is printed out to the console.

Here is the other program:

//import py4j.GatewayServer;
public class test {
 public static void addNumbers(int a, int b) {
 System.out.print(a + b);
 }
// public static void addNumbers(int a, int b) {
// System.out.print(a + b);
// }
 public static void main(String[] args) {
// GatewayServer gatewayServer = new GatewayServer(new test());
// gatewayServer.start();
// System.out.println("Gateway Server Started");
 test t = new test();
 t.addNumbers(5, 6);
 }
}

• user12377884: What error did you get?
• Perl Del Rey: @user12377884 no error, but output is not printed

Answer 1

The outputstream of the executed program test would become the inputstream for your current program run_java_program. Change your code to this and try:

import java.io.IOException;
public class run_java_program {
 public static void main(String[] args) {
 try {
 Process process = Runtime.getRuntime().exec("java -cp C:\\Users\96171円\\eclipse-workspace\\IR_Project\\src test");
 java.util.Scanner s = new java.util.Scanner(process.getInputStream());
 System.out.println(s.nextLine());
 } catch (IOException e) { 
 e.printStackTrace(); 
 } 
 }
}

I used Scanner as I know it returns only one line. Based on your need you can also use apache common utils.

• Perl Del Rey: Thank you so much, what if the other program prints several lines, how will I read all the lines printed out ??
• Sunil Dabburi: BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream())); and br.readLine() till it's null
• Perl Del Rey: It gives an error when u pass process.getInputStream(), I used this: stackoverflow.com/questions/4334808/… and thank you so much for the help!! You saved me lots of work!!