Java ProcessBuilder examples

In Java, we can use ProcessBuilder to call external commands easily :

	ProcessBuilder processBuilder = new ProcessBuilder();
	// -- Linux --
	// Run a shell command
	processBuilder.command("bash", "-c", "ls /home/mkyong/");
	// Run a shell script
	processBuilder.command("path/to/hello.sh");
	// -- Windows --
	// Run a command
	processBuilder.command("cmd.exe", "/c", "dir C:\\Users\\mkyong");
	// Run a bat file
	processBuilder.command("C:\\Users\\mkyong\\hello.bat");
	Process process = processBuilder.start();

1. Ping

1.1 Run an external ping command to ping a website 3 times, and display the output.

package com.mkyong.process;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class ProcessBuilderExample1 {
    public static void main(String[] args) {
        ProcessBuilder processBuilder = new ProcessBuilder();
        // Run this on Windows, cmd, /c = terminate after this run
        processBuilder.command("cmd.exe", "/c", "ping -n 3 google.com");
        try {
            Process process = processBuilder.start();
			// blocked :(
            BufferedReader reader =
                    new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            int exitCode = process.waitFor();
            System.out.println("\nExited with error code : " + exitCode);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();

Output

Pinging google.com [172.217.166.142] with 32 bytes of data:
Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
Ping statistics for 172.217.166.142:
    Packets: Sent = 3, Received = 3, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 10ms, Maximum = 10ms, Average = 10ms
Exited with error code : 0

2. Ping + Thread

In above example 1.1, the process.getInputStream is “blocking”, it is better to start a new Thread for the reading process, so that it won’t block other tasks.

package com.mkyong.process;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.List;
import java.util.concurrent.*;
import java.util.stream.Collectors;
public class ProcessBuilderExample2 {
    public static void main(String[] args) {
        ExecutorService pool = Executors.newSingleThreadExecutor();
        ProcessBuilder processBuilder = new ProcessBuilder();
        // Run this on Windows, cmd, /c = terminate after this run
        processBuilder.command("cmd.exe", "/c", "ping -n 3 google.com");
        try {
            Process process = processBuilder.start();
            System.out.println("process ping...");
            ProcessReadTask task = new ProcessReadTask(process.getInputStream());
            Future<list<string>> future = pool.submit(task);
            // no block, can do other tasks here
            System.out.println("process task1...");
            System.out.println("process task2...");
            List<string> result = future.get(5, TimeUnit.SECONDS);
            for (String s : result) {
                System.out.println(s);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            pool.shutdown();
    private static class ProcessReadTask implements Callable<list<string>> {
        private InputStream inputStream;
        public ProcessReadTask(InputStream inputStream) {
            this.inputStream = inputStream;
        @Override
        public List<string> call() {
            return new BufferedReader(new InputStreamReader(inputStream))
				.lines()
				.collect(Collectors.toList());

Output

process ping...
process task1...
process task2...
Pinging google.com [172.217.166.142] with 32 bytes of data:
Reply from 172.217.166.142: bytes=32 time=11ms TTL=55
Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
Reply from 172.217.166.142: bytes=32 time=10ms TTL=55
Ping statistics for 172.217.166.142:
    Packets: Sent = 3, Received = 3, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 10ms, Maximum = 11ms, Average = 10ms

3. Change Directory

3.1 Change to directory C:\\users and run external dir command to list out all the files.

package com.mkyong.process;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
public class ProcessBuilderExample3 {
    public static void main(String[] args) {
        ProcessBuilder processBuilder = new ProcessBuilder();
        processBuilder.command("cmd.exe", "/c", "dir");
        processBuilder.directory(new File("C:\\users"));
        // can also run the java file like this
        // processBuilder.command("java", "Hello");
        try {
            Process process = processBuilder.start();
            BufferedReader reader =
                    new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            int exitCode = process.waitFor();
            System.out.println("\nExited with error code : " + exitCode);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();

Output

 Volume in drive C has no label.
 Volume Serial Number is CE5B-B4C5
 Directory of C:\users
//...

References

1. Microsoft System Error Codes (0-499)
2. How to execute shell command from Java
3. Java docs – ProcessBuilder
4. What does cmd /C mean?