Question

/**
   *
   * @param extension
   * @return number of files with the given extension
   * (case insensitive)
   * NOTE: don't compare Strings using ==
   * Google "String case insensitive comparison java"
   */
   public int getCountByExtension(String extension) {
  
       return 0; //to be completed
   }

Answer 1

Program

import java.io.File;
import java.io.FilenameFilter;
import java.util.Scanner;

public class CountFileExtension
{

    public static void main(String[] args)
    {
        Scanner scnr=new Scanner(System.in);
    System.out.print("Enter extension: ");
           String ext=scnr.nextLine();
     System.out.print("Number of files: "+getCountByExtension(ext));
    }
    public static int getCountByExtension(String extension)
    {
        int count=0;
        File f = new File("C:\\Users\\Asha Ali\\Documents\\NetBeansProjects");
       
      
       for (File file : f.listFiles()) {
                       
                            if(file.toString().toLowerCase().endsWith(extension))
                            {
                                count++;
                        }
                }

        return count;
    }
}

Output

Enter extension:
.txt
Number of files: 22