Showcasing Java method references

A.java

import java.util.function.Supplier;

class A {

  static int staticSupplier() { return 5; }
  int instanceSupplier() { return 10; }

  static void printOut(Supplier<Integer> supplier) {
    System.out.println(supplier.get());
  }

  public static void main(String[] args) {
    A a = new A();

    printOut(A::staticSupplier);
    printOut(a::instanceSupplier);
  }
}