How do I start a browser in a remote ubuntu system?

Question

I am running two Ubuntu 12.04 machines. Machine A needs to start a browser (firefox or chrome) on machine B but it is not required for it to see the browser window. It just needs to start the browser and leave it. I have implemented it using JSch library (code snippet below) but this is the message that is returned - Error: no display specified

As a solution, on machine B, I set the DISPLAY variable to localhost:port or ipAddress:port where ipAddress is its own IP address and port is either 0 or some other number like 10 but it did not help.

The following works from machine A.

ssh -X <machine B ipAddress>
$firefox 

I am running Windows 7 as host and two Ubuntu 12.04 (one 32 bit another 64 bit) virtual machines on Virtualbox with a bridged network.

Code:

JSch jsch = new JSch();
Session session = jsch.getSession(user, ipAddress, 22);
session.setConfig("StrictHostKeyChecking", "no");
session.connect();

ChannelExec channelExec = null;
channelExec = (ChannelExec)session.openChannel("exec");
String command = "firefox -p project001 http://www.google.com";
channelExec.setCommand(command);
String port  = command.substring(20, 21); // which is "1"
String display = ipAddress + ":" + port;
channelExec.setEnv("DISPLAY", display);
//channelExec.setXForwarding(false);

channelExec.setInputStream(null);
InputStream err = channelExec.getErrStream();
InputStream in = channelExec.getInputStream();

channelExec.connect();

Any advice? Would appreciate any help either using JSch or anything else.

Update: If I update the command to run firefox in the background, it runs, except I cannot bring it to show the browser window.