Lazy evaluation of function in Java

SampleLazyEvaluation.java

import java.math.BigDecimal;
import java.util.function.Function;

import static java.lang.String.format;

class SampleLazyEvaluation {

    public static void main(String[] args) {

        Function<String, BigDecimal> asBigDecimal = BigDecimal::new;
        Function<Unit, BigDecimal> lazyAsBigDecimal = lazyApply(asBigDecimal, "3.00");
        System.out.println(format("Eager: %s, Lazy: %s",
                asBigDecimal.apply("3.00"), lazyAsBigDecimal.apply(Unit.unit())));
    }

    public static class Unit {

        private static final Unit unit = new Unit();

        public static Unit unit(){
            return unit;
        }
    }

    public static <A,B> Function<Unit, B> lazyApply(final Function<A, B> f, final A a){
        return unit -> f.apply(a);
    }
}