replaceAll() https://www.runoob.com/java/java-string-replaceall.html

import java.util.*;

public class Main{
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);

        while(sc.hasNextLine()){
//            String[] str = sc.nextLine().split("[^A-Za-z]+");
            String str = sc.nextLine();
            String replaceStr = str.replaceAll("[^A-Za-z]+", " ");
            String[] strArr = replaceStr.split(" ");
//            StringBuilder sb = new StringBuilder();
            for (int i = strArr.length - 1; i >= 0; i--) {

                System.out.print(strArr[i] + " ");
            }
        }
    }
}