Example using Java.awt.Robot class. In this example we will open a notepad and type a message.

TestRobot.java

import java.awt.AWTException;
import java.awt.Robot;
import java.awt.event.KeyEvent;

public class TestRobot {
	
	private Robot robot;
	private static final int SPEED = 300;
	
	private void execute(int[] letter){
		try {
			robot = new Robot();
		} catch (AWTException e) {
			e.printStackTrace();
		}
		for (int i = 0;i<letter.length ;i++ ) {
			robot.delay(SPEED);
			robot.keyPress(letter[i]);
			robot.keyRelease(letter[i]);
		}
	}

	public static void main(String[] args) {
		
		TestRobot t = new TestRobot();
		
		int[] executeNotepad = {KeyEvent.VK_WINDOWS,KeyEvent.VK_N,KeyEvent.VK_O,KeyEvent.VK_T,KeyEvent.VK_E,KeyEvent.VK_P,KeyEvent.VK_A,KeyEvent.VK_D,KeyEvent.VK_ENTER};
		int[] maximizeIt = {KeyEvent.VK_ALT,KeyEvent.VK_SPACE,KeyEvent.VK_X};
		int[] messageToPrint = {KeyEvent.VK_H,KeyEvent.VK_E,KeyEvent.VK_L,KeyEvent.VK_L,KeyEvent.VK_O};
		
		t.execute(executeNotepad);
		t.execute(maximizeIt);
		t.execute(messageToPrint);
		
	}

}

very cool!
I had to adjust a little to matter:
28 int[] maximizeIt = {KeyEvent.VK_ALT, KeyEvent.VK_SPACE, KeyEvent.VK_UP, KeyEvent.VK_UP, KeyEvent.VK_ENTER};