You don't create ScrollBars directly.
You can retrieve a reference to the ScrollBar by calling getHorizontalBar() or getVerticalBar().
Scrollable Styles:
StyleDescription
SWT.H_SCROLLCreates a horizontal ScrollBar (passes the SWT.HORIZONTAL style to ScrollBar's constructor)
SWT.V_SCROLLCreates a vertical ScrollBar (passes the SWT.VERTICAL style to ScrollBar's constructor)