Говорит, что не находит все слова.
package com.javarush.task.task19.task1907;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
/*
Считаем слово
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String nameFile = reader.readLine();
reader.close();
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new FileReader(nameFile));
String buff = "";
while ((buff = br.readLine()) != null) {
sb.append(buff);
}
br.close();
String str_1 = sb.toString().trim().replaceAll("[\\p{Punct}\\s]", " ");
String[] str_2 = str_1.trim().split(" ");
int count = 0;
for (int i = 0; i < str_2.length; i++) {
if (str_2[i].equals("world")){
count ++;
}
}
sb.delete(0, sb.length());
System.out.println(count);
}
}