Functional Interface - Java 8

The interface with only a single methods is known as functional interface. If an interface

marked as @FunctionalInterface it can only contains one abstract method. If we try to declare

more than one abstract method inside FunctionalInterface compiler will produce the error.

For example -

    @FunctionalInterface
    public interface MyDemoFunctionalInterface {
     public abstract void display();
    }

The above example is correct and will compile successfully, but the below example cannot be

compiled and will throw the error:

    @FunctionalInterface
    public interface MyDemoFunctionalInterface
    {
      public abstract void display();

      public abstract void show();
    }

Hope this will help you :)

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