Question

I currently have Java ME SDK 3.0.5 installed and am running a MIDLET from Eclipse.

When I run the app under the emulator device I get the following data in the console:

Syntax:

emulator [arguments]

In order to get commands supported by given device run:
emulator.exe -Xdevice:<device name> -Xquery

Generic list of arguments is:

-version           Display version information about the emulator
-help              Display list of valid arguments
-classpath, -cp    The class path for the VM
-D<name>=<value>   Set a system property
-Xdebug            Use a remote debugger
-Xrunjdwp:[transport=<transport>,address=<address>,server=<y/n>,
       suspend=<y/n>]
                   Debugging options
-Xdevice:<device>  Select a device skin for the emulator
-Xdomain:<domain_name>
               Set the MIDlet suite's security domain
-Xmain:<main class name>
                   Run the main method of a Java class, as in Java SE
-Xquery            Print device information

Everything seems to be alright, but I can’t get any form of emulation to appear.

here is the code of my MIDLET, although I don’t think the problem lies here.

 import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.lcdui.*;

public class Hello extends MIDlet implements CommandListener {

private Command exitCommand;
private Display display;
private Form screen;

public Hello() {
display = Display.getDisplay(this);

exitCommand = new Command ("Exit", Command.EXIT, 2);

screen = new Form ("Hello World");

StringItem strItem = new StringItem ("","Hello World");
screen.append (strItem);

screen.addCommand (exitCommand);
screen.setCommandListener(this);
}

public void startApp() throws MIDletStateChangeException {
    // set the current display to the screen
    display.setCurrent(screen);

}

public void pauseApp() {
    // TODO Auto-generated method stub

}


public void destroyApp(boolean unconditional)  {
    // TODO Auto-generated method stub

}


public void commandAction (Command c, Displayable s) 
{
    if (c == exitCommand) 
    {
        destroyApp (false);
        notifyDestroyed();
    }
}

}

Answer 1

The output is pretty simple, it’s telling you that the command line syntax to the emulator is incorrect.

Go to the Java ME device settings and edit the emulator command line / start options to suit.

Switching IDE’s may work for you as a short-term fix, but it’s always better to get to the root of the issue. Plus it’ll help you understand the emulator framework.