In general, you can define an interface as a place, where two systems come together and start interacting with each other. For example, an operating system acts as an interface between the computer and the user or acts as an interface between hardware and other application programs. Likewise in Java, the interface is a mechanism, using which programmers can connect different software components and make them interact with each other. In the following section you will get a clear picture of Java Interface.
This is a companion discussion topic for the original entry at http://iq.opengenus.org/interface-in-java/