Not entirely sure why after running my code, the smallest word and largest word are repeating null. Is there a way to remove it?

Below is the code:

import java.util.*;

public class PhraseAnalyzer { private String phrase; private String[] words; private boolean isValid; public PhraseAnalyzer(String phrase) { this.phrase = phrase; this.words = getWords(); this.isValid = isValidPhrase(); } private String[] getWords() { // split the phrase into words using whitespace as a delimiter return phrase.split("\\s+"); } private boolean isValidPhrase() { for (String word : words) { // check if the word contains only letters and ends with a punctuation mark if (!word.matches("[a-zA-Z]+[.,;:?!]*$")) { System.out.println("Phrase is not valid. Terminating."); System.exit(1); } } return words.length > 0; } public String[] getWordsArray() { return words; } public String[] getSmallestWords() { if (!isValid) { System.out.println("Phrase is not valid. Terminating."); System.exit(1); } Arrays.sort(words, Comparator.comparing(String::length)); return Arrays.copyOfRange(words, 0, 5); } public String[] getLargestWords() { if (!isValid) { System.out.println("Phrase is not valid. Terminating."); System.exit(1); } Arrays.sort(words, Comparator.comparing(String::length).reversed()); return Arrays.copyOfRange(words, 0, 5); } public double getAverageWordLength() { if (!isValid) { System.out.println("Phrase is not valid. Terminating."); System.exit(1); } int totalLength = 0; for (String word : words) { totalLength += word.length(); } return (double) totalLength / words.length; } public Map getLetterCounts() { if (!isValid) { System.out.println("Phrase is not valid. Terminating."); System.exit(1); } Map letterCounts = new HashMap<>(); for (String word : words) { for (char c : word.toCharArray()) { if (Character.isLetter(c)) { letterCounts.put(c, letterCounts.getOrDefault(c, 0) + 1); } } } return letterCounts; } public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.print("Enter a phrase: "); String phrase = scanner.nextLine(); PhraseAnalyzer analyzer = new PhraseAnalyzer(phrase); String[] smallestWords = analyzer.getSmallestWords(); String[] largestWords = analyzer.getLargestWords(); double averageWordLength = analyzer.getAverageWordLength(); Map letterCounts = analyzer.getLetterCounts(); System.out.println("Smallest words: " + String.join(", ", smallestWords)); System.out.println("Largest words: " + String.join(", ", largestWords)); System.out.println("Average word length: " + averageWordLength); System.out.println("Letter tally: " + letterCounts); }

}