import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;

public class Main {

    private static LamdaExampleClass lamdaExampleClass = new LamdaExampleClass();

    public static void main(String[] args) {
        List<String> list = Arrays.asList("elem1","elem2");
        list.forEach(s -> lamdaFu(s));//same as:
        list.forEach(Main::lamdaFu);//same as
        list.forEach(lamdaExampleClass);
    }

    private static void lamdaFu(String s) {
        System.out.println(s);
    }

    static class LamdaExampleClass implements Consumer<String>{

        @Override
        public void accept(String s) {
            System.out.println(s);
        }
    }
}