Starting a Play Application in browser window to allow user to answer the evolution page within a running Play Application in sbt using Java

I have a Play application that is running and I wanted to start up another Play application and open a browser window to start the application so the user can click on the Apply changes now button to allow the Evolution to happen. Once the button is clicked, I wanted to close the application - both the browser window and the running application in sbt.

It sounds like the Java Runtime.getRuntime().exec() method is the way to go, however the code I have written just hangs. It starts the application in sbt - in the same Windows command prompt that is running the current application - but never gets to the next command to open the browser window. There are no errors.

Here is the method I am calling:

public static void createTablesCMD(String appName, String mainTable, Database db, String mysqlusername,
		String mysqlpassword) throws IOException, Throwable {
	// Let's add the tables to the database we just built...
	// Start up sbt...
	String[] command = new String[] { "cmd", "/c", "C: && cd C:\\" + appName + " && sbt \"run 8080\"" };

	// Open the browser window...
	command = new String[] { "cmd", "/c", "start chrome http://localhost:8080" };

public static void executeRuntime(String[] command) throws IOException, Throwable {
	System.out.println("command: " + command);

	System.setProperty("user.dir", "C:\\");

	Runtime rt = Runtime.getRuntime();
	Process proc = rt.exec(command);
	// Any error message?
	StreamWriter errorWriter = new StreamWriter(proc.getErrorStream(), "ERROR");

	// Any output?
	StreamWriter outputWriter = new StreamWriter(proc.getInputStream(), "OUTPUT");

	// Start up the writers...

	// Any error?
	int exitVal = proc.waitFor();
	System.out.println("ExitValue: " + exitVal);

Here is the StreamWriter class:


public class StreamWriter extends Thread {
	InputStream is;
	String type;

	StreamWriter(InputStream is, String type) { = is;
		this.type = type;

	public void run() {
		try {
			InputStreamReader isr = new InputStreamReader(is);
			BufferedReader br = new BufferedReader(isr);
			String line = null;
			while ((line = br.readLine()) != null)
				System.out.println(type + ">" + line);
		} catch (IOException ioe) {

Here is the output:

command: [Ljava.lang.String;@10aff69
OUTPUT>Listening for transport dt_socket at address: 50933
OUTPUT>[info] Loading project definition from C:\MyApp\project
OUTPUT>[info] Set current project to MyApp (in build file:/C:/MyApp/)
OUTPUT>[info] Updating {file:/C:/MyApp/}root...
OUTPUT>[info] Resolving org.scala-lang#scala-library;2.11.8 ...
OUTPUT>[info] Resolving;1.1.0 ...
OUTPUT>[info] Done updating.
OUTPUT>--- (Running the application, auto-reloading is enabled) ---
OUTPUT>[info] p.c.s.NettyServer - Listening for HTTP on /0:0:0:0:0:0:0:0:8080
OUTPUT>(Server started, use Ctrl+D to stop and go back to the console...)

The first command runs fine - starting up sbt:

String[] command = new String[] { "cmd", "/c", "C: && cd C:\\" + appName + " && sbt \"run 8080\"" };

but it never completes - never hits the waitFor() code.

I found a few posts that I have been referring to:

Is this possible to do or is there a better way to handle this?

I appreciate the help.

It does not hits waitFor code or is it blocked there? waitFor javadocs state that:

Causes the current thread to wait, if necessary, until the process represented by this Process object has terminated.

But the process is still running. So no exit code and the thread is blocked waiting. Do you really need to block it there?


I appreciate the response. What would be an example of exit code? Would I be looking for a specific output?