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.
Do you mean you have a method which wants to know which method has invoked it?
I don't think that you are actually supposed to do that; the idea of a supplier class with public methods is that it is available to all objects without prejudice and without knowing whom it is serving. Bit like a bus; anybody can travel as long as they pay for their ticket, without the driver asking their name!