A sipmle Java example. Eager vs lazy evaluation with Supplier interface

SupplierExample.java

///usr/bin/env jbang "$0" "$@" ; exit $?

import static java.lang.System.*;
import java.util.List;
import java.util.function.Supplier;
import java.util.stream.Stream;

public final class SupplierExample {

    public static void main(String[] args) {
        var count = 5;
        eager(UnusedObject.createMany("Eager", count));
        lazy(() -> UnusedObject.createMany("Lazy", count));
    }
    
    private static void eager(List<UnusedObject> list){
        System.out.println("Eager thinks it didn't do anything");
    }

    private static void lazy(Supplier<List<UnusedObject>> listSupplier){
        System.out.println("Lazy is sure it didn't do anything");
    }

    private static final class UnusedObject {
        static List<UnusedObject> createMany(String caller, int count){
            return Stream.generate(UnusedObject::new)
                    .peek(unusedObject -> System.out.println(caller + " created unused object"))
                    .limit(count)
                    .toList();
        }
    }
}