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

Java example to get the index of the first occurrence of the specified item from LinkedList collection.
Submitted by Nidhi, on April 14, 2022

Problem Solution:

In this program, we will create a Linked List for country names using a Linked List collection. Then we will add items using add() method. After that, we will find the index of the first occurrence of the specified item from the LinkedList collection using the indexOf() method.

The indexOf() method returns the index of the first occurrence of the specified item from the LinkedList collection. If the specified item is not found in the LinkedList then it will return -1.

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.

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