Java imperative or functional

isPrime.java

public static boolean isPrimeFunctionalStyle(int number) {
	return number > 1 && 
			IntStream.rangeClosed(2, (int) Math.sqrt(number))
				.noneMatch(i -> number % i == 0);
}

lab1.java

import java.util.ArrayList;
import java.util.List;

public class Lab1 {

	/**
	 * Task: 
	 * Given a collection of names, for example "Josh", "Bruce", "Nate", "Sara", "Neal", "Jackie", "Jane", "Barb". Write two methods. 
	 * The first takes the collection, uses imperative style to total the number of characters in the names, and returns.
	 * The second method does the same thing but using declarative style.
	 * 
	 * @param args
	 */
	public static void main(String[] args) {	
		System.out.println("ImperativeStyle: " + imperativeStyle());
		System.out.println("DeclarativeStyle: " + declarativeStyle());
	}
	
	
	public static int imperativeStyle() {
		List<String> names = getCollection();
		
		int total = 0;
		for (String name : names) {
			total += name.length();
		}
		
		return total;
	}
	
	public static int declarativeStyle() {
		List<String> names = getCollection();
		
		return names
			.stream()
			.mapToInt(String::length)
			.sum();
	}
	
	public static List<String> getCollection() {
		List<String> names = new ArrayList<>();
		names.add("Josh");
		names.add("David");
		names.add("George");
		
		return names;
	}
}