Academic Java Knowledge, Problems with Movement in Games

I took a year of Java in college, but it was mostly academic/business-oriented coding. I am trying to make my first game, and I am at the point of having 2D graphics working in Swing and a character I can move back and forth, but I am having problems with ‘jumping’. Intending to make a 2D platformer, it is integral that I figure out vertical movement. As it stands I am using a KeyListener on my canvas to move the Entity object I have created, but my control scheme seems to be very primitive. I can make the Entity move left or right or jump, but it is unable to ‘jump’ and move a direction at the same time. I am using a switch statement to control the movement as such:

public void movement(KeyEvent e) {

	switch(e.getKeyCode()) {
	
	case KeyEvent.VK_RIGHT:
		
		if(myX >= 940) {
		
			break;
			
		}
		
		myX += 10;
		break;
		
	case KeyEvent.VK_LEFT:
		
		if(myX <= 10) {
			
			break;
			
		}
		
		myX -= 10;
		break;
	
	case KeyEvent.VK_SPACE:
		
                   while(myY < 400) {
			
			myY += 20;

		}

	       while(myY > 300) {

                            myY -= 20;

                   }

		break;
		
	}
	
}

What is the standard method of creating vertical/arcing movement of an Entity in 2D space? I apologize if this information is posted elsewhere, I couldn’t find it.
Thanks in advance,

boom_box