Open the text file and read each line as a String and place that String object into a LinkedList. Print all of the lines in the LinkedList in reverse order.

import java.util.*;
import java.io.*;

public class FileLinkList
{
public static void main(String args[])throws IOException{
String content = new String();
int count=1;
File file = new File("abc.txt");
LinkedList<String> list = new LinkedList<String>();

 try {
Scanner sc = new Scanner(new FileInputStream(file));
while (sc.hasNextLine()){
content = sc.nextLine();
list.add(content);
}
sc.close();
}catch(FileNotFoundException fnf){
fnf.printStackTrace();
}
catch (Exception e) {
e.printStackTrace();
System.out.println("\nProgram terminated Safely...");
}

Collections.reverse(list);
Iterator i = list.iterator();
while (i.hasNext()) {
System.out.print("Node " + (count++) + " : ");
System.out.println(i.next());
}
 }
 }

Below program demonstrates how file content can be added to a LinkedList.

import java.io.*;
import java.util.*;

public class UsingLinkedList
{
  public static void main(String[] args)
  {
    System.out.println("Enter meal plan file name :");
    Scanner input = new Scanner(System.in);
    String mealList = input.nextLine().trim();

    List<String> meals = new LinkedList<>();
    try
    {
      File inp1 = new File(mealList + ".txt");
      Scanner inputfile = new Scanner(inp1);
      while (inputfile.hasNextLine())
      {
        meals.add(inputfile.nextLine());
      }
      System.out.println(meals);
    }
    catch (FileNotFoundException exception)
    {
      exception.printStackTrace();
      System.out.println("File not found. Please re-enter the file name.");
    }
  }
}

For below input file content,

Meal plan 1
Meal plan 2
Meal plan 3
Meal plan 4

Output is:

Enter meal plan file name :
MealPlans
[Meal plan 1, Meal plan 2, Meal plan 3, Meal plan 4]

...
List<String> list = new ArrayList<String>();
// add to list
while (input.hasNext()) {
    list.add(input.next());
}
// display
for (String s : list) {
    System.out.println(s);
}

The problem is that you create the LinkedList in your fileIn.

But then you do not export it:

  fileIn f = new fileIn();
  LinkedList l = new LinkedList();

What you need is something like this:

  fileIn f = new fileIn();
  LinkedList l = f.readFileContents(String filename, new LinkedList()); 

Change the method to use the LinkedList you created and then populate it. So the fileIn class might look like something like this:

public class fileIn {
    ...
    public void readFileContents(String fileName, LinkedList) {
        // fill linked list
    }
    ...
}