This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
class myClass needs methods implemented by other three classes ,Not by creating a reference variable of these 3 in my class but by some other way. I know multiple inheritance is not allowed in java...yet i want to know
You can't. You either need to create an instance of each class or make the methods static. The latter may not be possible if the method implements an interface method or overrides a method from a super class.