Qual a diferença entre os codigos

import org.eclipse.jface.window.*;
import org.eclipse.swt.widgets.*;

public class Principal{
	public static void main(String args[]){
		ApplicationWindow apw = new ApplicationWindow(null);
		apw.setBlockOnOpen(true);
		apw.open();
		Display.getCurrent().dispose();
	}
}

import org.eclipse.swt.widgets.*;

public class Principal{
	public static void main(String args[]){
		Display dsp = new Display();
		Shell shl = new Shell(dsp);
		
		shl.open();
		
		while(!shl.isDisposed())
			if (!dsp.readAndDispatch()){
				dsp.sleep();  
			}
			dsp.dispose();
	}
}