Java App To Open A Console Base Program And Run A Command

I am struggling getting my java app to open a console window on either MacOS or windows and run a command. On windows I can get the cmd.exe program to open, but it won't execute the command. On MacOS, I cannot get it to even open the terminal.

String run = "c:
s34bil.exe
elap5.exe" + in + rst + out; //in, rst, out are parameters for the relpa5.exe file.
try {
Runtime rt = Runtime.getRuntime();
rt.exec(new String[]{"cmd.exe","/c",run,"start"});
} catch (IOException ex) {
Logger.getLogger(issrsUI.class.getName()).log(Level.SEVERE, null, ex);
}