创建Shell窗体生成的代码？

[hhsjwxh]

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;


public class dsafsdf extends Shell {

/**
* Launch the application
* @param args
*/
public static void main(String args[]) {
try {
Display display = Display.getDefault();
dsafsdf shell = new dsafsdf(display, SWT.SHELL_TRIM);
shell.open();
shell.layout();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* Create the shell
* @param display
* @param style
*/
public dsafsdf(Display display, int style) {
super(display, style);
createContents();
}

/**
* Create contents of the window
*/
protected void createContents() {
setText("SWT Application");
setSize(500, 375);
//
}

@Override
protected void checkSubclass() {
// Disable the check that prevents subclassing of SWT components
}

}
===================================================================

以上是创建可视化Shell窗体自动生成的代码！！和我以前手写不一样！！有的地方不是很理解！！请帮我加注释解释下... 越详细越好！！非常感谢！！！！