Wywołania zwrotne tzw. callback w java

package wypisywanie_zawartosci_katalogu;

import java.io.File;
import java.io.FilenameFilter;
import java.util.regex.Pattern;

public class Wypisywanie_zawartosci_katalogu {
    public static void main(String[] args) {

        
        File path = new File(".");
        String[] list;
        if(args.length == 0){
            list = path.list();
            for(String l : list)
            System.out.println(l);
        }
        else
        {  
            list = path.list(new DirFilter(args[0]));
            for(String l : list)
            System.out.println(l);
            
        }
    }
    
}

class DirFilter implements FilenameFilter
{

    private Pattern pattern;
    public DirFilter(String regex){
        pattern = Pattern.compile(regex);
        
    }

   
    @Override
    public boolean accept(File dir, String name) {
      System.out.println("Wywołano accept" + name);
        return pattern.matcher(name).matches();
    }
    
} 

    public String[] list(FilenameFilter filter) {
        String names[] = list();
        if ((names == null) || (filter == null)) {
            return names;
        }
        List<String> v = new ArrayList<>();
        for (int i = 0 ; i < names.length ; i++) {
            if (filter.accept(this, names[i])) {
                v.add(names[i]);
            }
        }
        return v.toArray(new String[v.size()]);
    }