Do interfaces have member variables?

Question

I know that interfaces have method definitions but can they have member variables as well?

Answer 1

Yes, Interfaces CAN contain member variables. But these variables have to be implicitly (without any keyword definition) final, public and static. This means that within interfaces, one can only declare constants. You cannot declare instance variables using interfaces.   

Interfaces are critical to certain aspects of JAVA programming. If you're looking to learn java from scratch, consider using complex concepts such as interfaces from the ground up for basic code problems.