This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
So you've found examples that sort all columns when a single column header is clicked - surely it can't be hard to change that to only sort a single column? Or am I misunderstanding what you're asking?