Java 8 method reference to class instance method NPE

Question

import java.util.function.Function;

public class Playground {
    public static void main (String[] args) {
        Object o = null;
        System.out.println(o);
             


        

Answer 1

when you do

toStringFunc.apply(o);

this is the same that

o.toString()

that's why you get a NullPointerException so, you must ensure that your Object is not null.