https://www.hackerrank.com/challenges/java-string-tokens

Java String Tokens.java

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(final String[] args) {
        final Scanner scan = new Scanner(System.in);
        if (!scan.hasNext()) {
            System.out.print("0");
            return;
        }

        final String s = scan.nextLine();
        final String[] items = s.trim().split("[ !,?.\\_'@]+");

        if (s == "") {
            System.out.println("0");
        } else if (s.length() > 400000) {
            return;
        } else {
            System.out.println(items.length);
        }

        for (final String item : items) {
            System.out.println(item);
        }
        scan.close();
    }
}