Question

The difference of abstract and interface in java ???

Answer 1

An abstract class may or may not have an implementation for a method(there can be a few lines of code for a method in a abstract class) but in an interface, the method can have no implementation. An interface contains only method signatures and final static variables.

Answer 2

and what's the usage of each of them?

Answer 3

It does not have any specific usage, you may have to use them any time. No such examples are coming to my head right now.

Answer 4

for example we use interface when we want someone do GUI and someone else do implementations wright?

Answer 5

*right

Answer 6

yeah, kind of :)

Answer 7

thanks :)