blad Uncompilable source code

<codepackage frequency;

import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.HashMap;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Main {

public static void main(String[] args) {

    Reader rdr;
    int c;
    int charCount = 0;
    char a;
    HashMap<Character, Integer> map;

    map = new HashMap<Character, Integer>();



    try {
        rdr = new FileReader("C:\\Users\\chudy\\Desktop\\dupa.txt");
        while ((c = rdr.read()) != -1) {
            a = (char) c;
            if (Character.isWhitespace(a) == false) {
                charCount++;
                if (map.containsKey(a)) {
                    map.put(a, map.get(a) + 1);
                }
            } else {
                map.put(a, 1);
            }

        }
        rdr.close();
        System.out.println("Total number of characters: " + charCount);
    } catch (IOException ex) {
        Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
    }
    displayResults(map);

}

public void displayResults(HashMap<Character, Integer> _map) {
    for (char c : _map.keySet()) {
        System.out.println(c);
    }

}

}

Gdy kompiluje powyzszy kod wyskakuje mi blad : Uncompilable source code - non-static method displayResults(java.util.HashMap<java.lang.Character,java.lang.Integer>) cannot be referenced from a static context

Jak temu zaradzic?

Umieścić metodę displayResults w odpowiedniej klasie, a nie w main()