java method reference

1public class Main {
2  public static void main(String args[]) {
3    SayHi();
4    
5    int sum = AddNums(5, 6);
6    System.out.println(sum);
7  }
8  
9  public static void SayHi() { //This method has no return value
10    System.out.println("Hi!");
11  }
12  
13  public static int AddNums(int a, int b) { //This method has a return value
14    return a + b;
15}

1Java provides a feature called method
2reference in Java 8. Method reference 
3is used to refer method of functional interface.
4  It is compact and easy form
5  of lambda expression. Each time when 
6  you are using lambda expression to just
7  referring a method, you can replace your
8  lambda expression with method reference.
9
10Types of Method References:
11- Reference to a static method.  Syntax ==> ContainingClass::staticMethodName  
12- Reference to an instance method.  Syntax ==> containingObject::instanceMethodName  
13- Reference to a constructor.  Syntax ==> ClassName::new