How to find files with certain extension only

package com.mkyong.io;
 
import java.io.*;
 
public class FileChecker {
 
	private static final String FILE_DIR = "c:\\folder";
	private static final String FILE_TEXT_EXT = ".jpg";
 
	public static void main(String args[]) {
		new FileChecker().deleteFile(FILE_DIR,FILE_TEXT_EXT);
	}
 
	public void deleteFile(String folder, String ext){
 
		GenericExtFilter filter = new GenericExtFilter(ext);
 
	    File dir = new File(folder);
	    //list out all the file name with .txt extension
	    String[] list = dir.list(filter);
 
	    if (list.length == 0) {
	    	System.out.println("no files end with : " + ext);
	    	return;
	    }
 
	    for (String file : list){
	    	String temp = new StringBuffer(FILE_DIR)
                                   .append(File.separator)
                                   .append(file).toString();
	    	System.out.println("file : " + temp);
	    }
	}
 
	//inner class, generic extension filter 
	public class GenericExtFilter implements FilenameFilter {
 
	       private String ext;
 
	       public GenericExtFilter(String ext) {
	         this.ext = ext;             
	       }
 
	       public boolean accept(File dir, String name) {
	         return (name.endsWith(ext));
	       }
	 }
}