In Java

Problem Description

FileDisplay class
Write a class named FileDisplay with the following methods:
-Constructor. The class's constructor should take the name of the file as an argument.
-displayHead. This method should only the first five lines of the file's contents. If the file contains less than five lines, it should display the file's entire content.
-displayContents. This method should display the entire contents of the file, the name of which was passed to the constructor.
-displayWithLineNumbers. This method should display the contents of the file, the name of which was passed to the constructor. Each line should be preceded with a line number followed by a colon. The line numbering should start at 1.

This is my code it compile but it gives me this message "Exception in thread "main" java.io.FileNotFoundException: input.txt (The system cannot find the file specified)" I need help

import java.io.BufferedReader;
import java.io.FileReader;


class FilePrint
{
     private String fileName;
     public FilePrint(String aFileName)
   {
      super();
      fileName=aFileName;
    }
    public void displayHead()throws Exception
   {
      BufferedReader br=null;
      br=new BufferedReader(new FileReader(fileName));
     int no=1;
     String line=br.readLine();
     while(line!=null&&no<=5)
      {
         System.out.println(line);
         line=br.readLine();
        no++;
      }
     br.close();
  }
public void displayContents()throws Exception
{
      BufferedReader br=null;
      br=new BufferedReader(new FileReader(fileName));
      String line= br.readLine();
      while(line!=null)
   {
      System.out.println(line);
      line=br.readLine();
    }
     br.close();
   }
      public void displayWithLineNumbers()throws Exception
      {
         BufferedReader br=null;
         br=new BufferedReader(new FileReader(fileName));
         String line= br.readLine();
         int n=1;
        while(line!=null)
          {
             System.out.println(n+""+line);
              line=br.readLine();
              n++;
           }
       br.close();
      }
}
public class TestFilePrint
{
       public static void main(String[]args)throws Exception
       {
          FilePrint fp=new FilePrint("input.txt");
           fp.displayContents();
          System.out.println();
          System.out.println();
         fp.displayWithLineNumbers();
        }
}