Como chamar métodos da mesma classe

package atividade3;
import java.util.*;
import java.io.File;
import java.io.FileNotFoundException;
import java.lang.String;
/*
 * AXXXXXO
 * MATRÍCULA/LOGIN XXXXXXX
 */
public class Atividade3 {
    
   public String nomearquivo = "pg33056.txt";
   public String nome_arquivo = nomearquivo ;
    
    public static void main(String[] args) throws FileNotFoundException{
        
        //leHashSet();
        //leTreeSet();
       // leLinkedList();       
    } 
    
  
    void leLinkedList(String nome_arquivo) throws FileNotFoundException{
        LinkedList<String> words = new LinkedList<String>();
        long totalTime = 0; 
        
        Scanner in = new Scanner(new File(nome_arquivo));
               while (in.hasNext())
        {
            String word = in.next();
            long callTime = System.currentTimeMillis();
            words.add(word);
            callTime = System.currentTimeMillis() - callTime;
            totalTime += callTime;            
        }
        Iterator<String> iter = words.iterator();
        for (int i=1;i<=20 && iter.hasNext();i++)
            System.out.println(iter.next());
        System.out.println("--------------------------------------------------------------------------");
        System.out.println("Lendo arquivo para LinkedList...");
        System.out.println("Em LinkedList foram achadas " + words.size() + " palavras. " + totalTime + " milliseconds.");
    
    }
    
    void leTreeSet(String nome_arquivo) throws FileNotFoundException{
        LinkedList<String> words = new LinkedList<String>();
        long totalTime = 0; 
        
        Scanner in = new Scanner(new File(nome_arquivo));
               while (in.hasNext())
        {
            String word = in.next();
            long callTime = System.currentTimeMillis();
            words.add(word);
            callTime = System.currentTimeMillis() - callTime;
            totalTime += callTime;            
        }
        Iterator<String> iter = words.iterator();
        for (int i=1;i<=20 && iter.hasNext();i++)
            System.out.println(iter.next());
        System.out.println("--------------------------------------------------------------------------");
        System.out.println("Lendo arquivo para TreeSet...");
        System.out.println("Em TreeSet foram achadas " + words.size() + " palavras diferentes. " + totalTime + " milliseconds.");
    
    }
    
    void leHashSet(String nome_arquivo) throws FileNotFoundException{
        LinkedList<String> words = new LinkedList<String>();
        long totalTime = 0; 
        
        Scanner in = new Scanner(new File(nome_arquivo));
               while (in.hasNext())
        {
            String word = in.next();
            long callTime = System.currentTimeMillis();
            words.add(word);
            callTime = System.currentTimeMillis() - callTime;
            totalTime += callTime;            
        }
        Iterator<String> iter = words.iterator();
        for (int i=1;i<=20 && iter.hasNext();i++)
            System.out.println(iter.next());
        System.out.println("--------------------------------------------------------------------------");
        System.out.println("Lendo arquivo para HashSet...");
        System.out.println("Em HashSet foram achadas " + words.size() + " palavras diferentes. " + totalTime + " milliseconds.");
    
    }
}