GWT: Timer and Scheduler Classes

Use Scheduler when you need a browser to complete whatever it is currently doing before you tell it to do something else. For example:

myDialogBox.show();
Scheduler.get().scheduleDeferred(new ScheduledCommand() {

    @Override
    public void execute() {
        myTextBox.setFocus();
    }
});

In this example, focus will not be set until the browser completes rendering of the dialog, so you tell the program to wait until the browser is ready.

Use Timer if you want some action to happen after a specified period of time. For example:

 notificationPanel.show();
 Timer timer = new Timer() {
     @Override
     public void run() {
         notificationPanel.hide();
     }
 };
 timer.schedule(10000);

This code will show notificationPanel, and then it will hide it after 10 seconds.