Adding vertical scroll bar to a text area in RCP is straightforward. You should use SWT static field value to set the style.
Text text = new Text(top, SWT.MULTI | SWT.V_SCROLL | SWT.BORDER);
* This answer is from the book "Eclipse Rich Client Platform 2nd" which explains details like this very well.
<pre><code> String foo = "bar"; </code></pre>