java调用dos命令

import java.io.IOException;


public class Te {

/**
 * @param args
 * @throws IOException 
 * @throws IOException 
 * @throws InterruptedException 
 */
public static void main(String[] args) throws IOException, InterruptedException {
// TODO Auto-generated method stub
Process process = Runtime.getRuntime().exec("cmd.exe  dir"); 
process.waitFor( );
}
}

我这个程序为什么运行到process.waitFor();就会卡住，如何解决
[解决办法]
Process process = Runtime.getRuntime().exec("cmd.exe /c start dir");