Program/Source Code:

The source code to get the index of the first occurrence of the specified item from the LinkedList collection is given below. The given program is compiled and executed successfully.

// Java program to get the index of the first occurrence of the 
// item from LinkedList collection

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");
    countries.add("USA");

    System.out.println("Country names: " + countries);
    System.out.println("Index of USA: " + countries.indexOf("USA"));
    System.out.println("Index of PAK: " + countries.indexOf("PAK"));
  }
}

Output:

Country names: [India, USA, UK, CANADA, USA]
Index of USA: 1
Index of PAK: -1

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 got the index of the first occurrence of the specified item from LinkedList using the indexOf() method and printed the result.