Java .contains()

The .contains() method is declared in the List interface and implemented in the ArrayList class. It is used to check if the element is present in the specified ArrayList or not. The function returns a boolean value of true if the element is present and false if not.

Syntax

The .contains() method can be called on an ArrayList instance and requires a single parameter:

arrayListInstance.contains(obj);

• arrayListInstance: The ArrayList on which the .contains() method is called.
• obj: The element whose presence in the ArrayList is to be checked.

Example

In the example below, an empty ArrayList instance fruitList is created, which can hold String type elements. Next, a few fruit names are added with the .add() method. Lastly, the presence of two fruit names is checked in the ArrayList with the .contains() method:

import java.util.ArrayList;

public class Fruits {
  public static void main(String[] args) {

    ArrayList<String> fruitList = new ArrayList<String>();

    fruitList.add("Mangos");
    fruitList.add("Bananas");
    fruitList.add("Watermelons");
    fruitList.add("Grapes");

    // Checking if 'Oranges' and 'Bananas' are present in 'fruitList'
    boolean areOrangesPresent = fruitList.contains("Oranges");
    boolean areBananasPresent = fruitList.contains("Bananas");

    System.out.println("Fruit list contains oranges: "+ areOrangesPresent);
    System.out.println("Fruit list contains bananas: "+ areBananasPresent);
  }
}

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The output of the above example will look like this:

Fruit list contains oranges: false
Fruit list contains bananas: true

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