How I can catch command event in j2me?

In your commandAction(Command,Displayable) for the CommandListener for that screen, you would use the following code pattern:

public void commandAction(Command c,Displayable d)
{
switch(c.getCommandType())
{
case Command.OK: // this is the OK command
// do your stuff
}
}

//try this it will help when you use threads in the command actions.

private Command cmdSave;
private Command cmdNext;
public void commandAction(Command c, Displayable d) {
if (c==cmdSave)
{
Thread th1 = new Thread()
{
public void run()
{
try {
METHOD();//call your method here
} catch (IOException ex) {
ex.printStackTrace();
}
}
};
th1.start();
}
else if (c==cmdNext)
{
//check if all the required fields have been filled
Thread tha = new Thread()
{
public void run()
{
METHOD2();
}
};
tha.start();
}

private void METHOD()
{
//code code code
}