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.
In Java, you don't need to know the memory address of an object. Java does not have pointers like you have in C, and you never need to deal with things such as the addresses of objects in memory. So forget about things like memory addresses when you're programming in Java - it doesn't apply and will confuse you if you try to apply those ideas from C to Java.
As Pete says, you can use the == operator to check if two variables refer to the same object in memory.