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


public class DirList {

     public static void main(String[] args) {
            
            String filePath="d:\\";    
            String filterName=".java";    
            FilenameFilter ff = new DirFilter(filterName);    
            File f = new File(filePath);        
            String[] list = f.list(ff);
          
            Arrays.sort(list,String.CASE_INSENSITIVE_ORDER);
            for(String dirItem : list){
                System.out.println(dirItem);
            }
     }

     static  class DirFilter implements FilenameFilter{
         
         private Pattern pattern;
         public DirFilter(String regex){
             pattern = Pattern.compile(regex);
         }
         public boolean accept(File dirFile , String name){
             return pattern.matcher(name).matches();
         }
         
     }


}