Calling a command line program in Java

You'd have to do this in two steps:

1. Extract the binary and write it to disk (because the OS is probably only able to launch the program if it's a file on disk)

2. Launch the program, preferably using ProcessBuilder.

Here's a complete demo:

test.c

#include <stdio.h>

int main() {
    printf("Hello world\n");
    return 0;
}

Test.java

import java.io.*;
import java.nio.file.*;
import java.nio.file.attribute.PosixFilePermission;
import java.util.Collections;

public class Test {
    public static void main(String[] args) throws Exception {

        Path binary = Paths.get("mybinary");
        Files.copy(Test.class.getResourceAsStream("mybinary"), binary);

        System.out.println("Launching external program...");

        // Needed for Linux at least
        Files.setPosixFilePermissions(binary,
                Collections.singleton(PosixFilePermission.OWNER_EXECUTE));

        Process p = new ProcessBuilder("./mybinary").inheritIO().start();
        p.waitFor();
        System.out.println("External program finished.");
    }
}

Demo

$ cc mybinary.c -o mybinary
$ ./mybinary
Hello world
$ javac Test.java
$ jar -cvf Test.jar Test.class mybinary
$ rm mybinary Test.class
$ ls
mybinary.c  Test.jar  Test.java
$ java -cp Test.jar Test
Launching external program...
Hello world
External program finished.

Further reading:

• Run external program concurrently and communicate with it through stdin / stdout
• How to make an executable jar file?
• Where does Java's ProcessBuilder look to execute commands?
• ProcessBuilder won't run with arguments