How to Search an Element in ArrayList in Java

This example demonstrates how to search an element in ArrayList in Java.

Search an Element in ArrayList in Java Example

The example below shows how to:

• Check if an ArrayList contains a given element | contains()
• Find the index of the first occurrence of an element in an ArrayList | indexOf()
• Find the index of the last occurrence of an element in an ArrayList | lastIndexOf()

import java.util.ArrayList;
import java.util.List;

public class SearchElementsInArrayListExample {
    public static void main(String[] args) {
        List<String> names = new ArrayList<>();
        names.add("John");
        names.add("Alice");
        names.add("Bob");
        names.add("Steve");
        names.add("John");
        names.add("Steve");
        names.add("Maria");

        // Check if an ArrayList contains a given element
        System.out.println("Does names array contain \"Bob\"? : " + names.contains("Bob"));

        // Find the index of the first occurrence of an element in an ArrayList
        System.out.println("indexOf \"Steve\": " + names.indexOf("Steve"));
        System.out.println("indexOf \"Mark\": " + names.indexOf("Mark"));

        // Find the index of the last occurrence of an element in an ArrayList
        System.out.println("lastIndexOf \"John\" : " + names.lastIndexOf("John"));
        System.out.println("lastIndexOf \"Bill\" : " + names.lastIndexOf("Bill"));
    }
}

Output

Does names array contain "Bob"? : true
indexOf "Steve": 3
indexOf "Mark": -1
lastIndexOf "John" : 4
lastIndexOf "Bill" : -1

Reference

https://www.javaguides.net/2018/11/java-arraylist-class-methods-with-examples.html