Как проверить?
package com.javarush.task.task19.task1907;
/*
Считаем слово
*/
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Solution {
public static void main(String[] args) {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s1 = null;
try {
s1 = br.readLine();
} catch (IOException e) {
e.printStackTrace();
}
try {
FileReader fr = new FileReader(s1);
String res = "";
while (fr.ready()) {
res = res + (char) fr.read();
}
br.close();
fr.close();
int cnt = 0;
int index = 0;
if (!res.isEmpty()) {
while ((index = res.indexOf("world", index)) >= 0) {
cnt++;
index=index + 5;
}
System.out.println(cnt);
} else {
System.out.println(0);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}