SortContent.java

import java.util.*;

public class SortContent {
  public static String sortTheInnerContent(String words) {
    String[] wordArr = words.split(" ");
    String[] solution = new String[wordArr.length];
    int i = 0;
    for (String word: wordArr) {
      if (word.length() > 3) {
        String sortedWord = word.substring(1, word.length() - 1);
        char[] sortedChars = sortedWord.toCharArray();
        Arrays.sort(sortedChars);

        for (int j = 0; j < sortedChars.length / 2; j++) {
          char tmp = sortedChars[j];
          int index = sortedChars.length - 1 - j;
          sortedChars[j] = sortedChars[index];
          sortedChars[index] = tmp;
        }

        solution[i] = word.charAt(0) + new String(sortedChars) + word.charAt(word.length() - 1);
      } else {
        solution[i] = word;
      }
      i++;
    }
    return String.join(" ", solution);
  }
}