java 8 functional interfaces

1package com.concretepage;
2
3@FunctionalInterface
4public interface Calculator {
5   long calculate(long num1, long num2);
6} 

1@FunctionalInterface
2interface Square
3{
4    int calculate(int x);
5}
6  
7class Test
8{
9    public static void main(String args[])
10    {
11        int a = 5;
12  
13        // lambda expression to define the calculate method
14        Square s = (int x)->x*x;
15  
16        // parameter passed and return type must be
17        // same as defined in the prototype
18        int ans = s.calculate(a);
19        System.out.println(ans);
20    }
21}

1interface SearchFunc {
2  (source: string, subString: string): boolean;
3}

1Supplier       ()    -> x
2Consumer       x     -> ()
3Callable       ()    -> x throws ex
4Runnable       ()    -> ()
5Function       x     -> y
6BiFunction     x,y   -> z
7Predicate      x     -> boolean
8UnaryOperator  x1    -> x2
9BinaryOperator x1,x2 -> x3
10