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.
If you need only one of those Observer panels in your application, then just create one of them. There's usually no need to go through all that tedious Singleton business when a simple "Observer whatever = new ObserverPanel()" will do.