If you need tooltips for elements in an SWT Tree or JFace TreeViewer, you had to jump through some hoops as Snippet 125 shows.
Since SWT/JFace 3.3, you should use a TreeViewer, a ColumnLabelProvider (which has all those cool getTooltip…() methods) and this line of code:
ColumnViewerToolTipSupport.enableFor (viewer);
That’s it. There is a catch, though: The tooltip doesn’t wrap automatically. If you have long lines of text, you need commons-lang and this piece of code:
private String wrap (String s)
{
StringBuilder buffer = new StringBuilder ();
String delim = "";
for (String line: s.trim ().split ("\n"))
{
buffer.append (delim);
delim = "\n";
buffer.append (WordUtils.wrap (line, 60, "\n", true));
}
return buffer.toString ();
}
Note that this code is only necessary if you have several lines of text in the tooltip. For single long lines, WordUtils.wrap() alone is enough.
Dark Views 
Nice. This will help to wrap the text. What if the text in length is huge (vertically), are we going to get scroll bars ?
I don’t know. It’s been a while since I used SWT. I don’t think scrollbars are added automatically.
That said, tooltips are for small amounts of text. If you have a long test, they are the wrong tool. You should use a popup of some kind instead (button plus new window with proper UI).
If you need scrollbars, try to override ColumnViewerToolTipSupport.createToolTipContentArea() to create a more complex layout.