Program/Source Code:

The source code to check whether an item exists in the LinkedList collection or not is given below. The given program is compiled and executed successfully.

// Java program to check whether an item exists in 
// LinkedList collection or not

import java.util.LinkedList;

public class Main {
  public static void main(String[] args) {
    LinkedList < String > countries = new LinkedList < String > ();

    countries.add("India");
    countries.add("USA");
    countries.add("UK");
    countries.add("CANADA");

    System.out.println("Country names: " + countries);

    if (countries.contains("UK") == true)
      System.out.println("Item exists.");
    else
      System.out.println("Item does not exists.");
  }
}

Output:

Country names: [India, USA, UK, CANADA]
Item exists.

Explanation:

In the above program, we imported the "java.util.LinkedList" package to use the LinkedList collection class. Here, we created a class Main. The Main class contains a main() method. The main() method is the entry point for the program.

In the main() method, we created an object of the LinkedList collection class to store country names. Here, we added country names using add() method. Then we checked an item is exist or not, in created collection using contains() method and printed the appropriate message.