Java program that relaunches itself in OS's terminal application

Question

I wrote a Java program that when its executable .jar is opened manually, it re-opens itself inside the operating system's shell console. The purpose of this is to have a C#-style console application where the user can enter commands, without the user needing to manually open the shell console and run the java -jar ... command to open the application.

Would you consider this a good implementation?

Would you make a custom console GUI instead of using the OS's console?

public static void main(String[] args){
    if(args.length == 0){ // then re-open in console with argument to indicate that there's no need to re-open next time.
        try {
            String os = System.getProperty("os.name").toLowerCase();
            String path = new File(Main.class.getProtectionDomain().getCodeSource().getLocation().toURI()).getAbsolutePath();
            if(os.contains("mac")){
                String command = "tell application \"Terminal\"\n" + 
                        "do script \"java -jar \'" + path + "\' console\"\n" + 
                        "activate\n" + 
                        "end tell";
                Runtime.getRuntime().exec( new String[]{"osascript", "-e", command} );
                System.exit(0);
            } else if(os.contains("win")) {
                Runtime.getRuntime().exec("cmd /c start cmd.exe /K java -jar \"" + path + "\" console");
                System.exit(0);
            }
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
    System.out.println("Enter command.  'help' for list of commands.");
    while(true)
        nextCommand();
}

Answer 1

A few empty lines here and there would do wonders to the readability.

---

This will also relaunch the application if it was started from a terminal without arguments.

---

String path = new File(Main.class.getProtectionDomain().getCodeSource().getLocation().toURI()).getAbsolutePath();

---

String os = System.getProperty("os.name").toLowerCase();
...
if(os.contains("mac")){

Unfortunately that is a quite fragile way to detect the current operating system, but it will do.

---

On nay other operating system, you simply start reading commands (or not), are you aware of that?

You should have the command reading in an else branch.

---

System.exit(0);

Please stop sprinkling your code with those. System.exit makes the JVM exit immediately, it is like a SIGKILL on UNIX. That means that not even final branches are being run when invoked.

---

while(true)
    nextCommand();

I assume that there is a "quit" command which calls System.exit, that might be a bad idea. A better idea would be to have something like this:

while(commandExecutor.isActive()) {
    commandExecutor.readAndExecuteCommand());
}