code review for 7067811: Update demo/sample code to state it should not be used for production

[Nils Loodin]

Added a comment in each demo source file stating that the code below is 
unfit for production.
Made a separate comment blog from the copyright one to make it stand out 
more and be more warning-like :)

http://cr.openjdk.java.net/~nloodin/7067811/webrev.00/
/Nisse