import java.util.Set; import java.util.HashSet; public class Main { public static void main(String[] args) { String text = "Hello Java"; Set<Character> vowels = new HashSet<>(); for (char v : new char[]{'a','e','i','o','u'}) { vowels.add(v); } int count = 0; for (char c : text.toLowerCase().toCharArray()) { if (vowels.contains(c)) { count++; } } System.out.println("Vowels: " + count); } }