java - Is this file object left open? -

as exercise school wrote method in java searches character in file. here code:

 public static void countletter(char needle, string haystack) throws ioexception {          file f = new file(haystack);                                                    try (scanner in = new scanner(f)) {                                                 string str = null;                                                              while (in.hasnext()){                                                               str += in.next();                                                           }                                                                               char[] chararr = str.tochararray();                                             int counter = 0;                                                                (char c: chararr) {                                                             if (c == needle){                                                                   counter++;                                                                  }                                                                           }                                                                               system.out.println(counter);                                                }                                                                           } 

this need have question. is file object ever opened? , if is, ever closed? used try-with-resources on scanner object i'm pretty sure don't have explicitly close that, file object?

file object abstract representation of pathname, has nothing opening file. can not closed.