What is meant by Interface?

Multiple inheritances cannot be achieved in java. To overcome this problem the Interface concept is introduced.

An interface is a template which has only method declarations and not the method implementation.

Example:

Public abstract interface IManupulation{ //Interface declaration
Public abstract void add();//method declaration
public abstract void subtract();
}

• All the methods in the interface are internally public abstract void.
• All the variables in the interface are internally public static final that is constants.
• Classes can implement the interface and not extends.
• The class which implements the interface should provide an implementation for all the methods declared in the interface.

public class Manupulation implements IManupulation{ //Manupulation class uses the interface
Public void add(){
……………
}
Public void subtract(){
…………….
}
}