ArrayDeque forEach() method in Java (original) (raw)

Last Updated : 08 Mar, 2024

The **forEach() method of **ArrayDeque is inherited from interface **java.lang.Iterable. The operation is performed in the order of iteration if that order is specified by the method. Method traverses each element of the Iterable of ArrayDeque until all elements have been processed by the method or an exception occurs. Exceptions thrown by the Operation are passed to the caller.

**Syntax:

public void forEach(Consumer<? super E> action)

**Parameter: This method takes a parameter name **action which represents the action to be performed for each element.
**Returns: This method returns Nothing.
**Exception: This method throws **NullPointerException if the specified action is null.

Example of ArrayDeque forEach() Method

The below programs illustrate forEach() method of ArrayDeque:

**Example 1:

To demonstrate the forEach() method on ArrayDeque which contains a queue of String values.

Java `

// Java Program Demonstrate forEach() // method of ArrayDeque import java.util.*;

// Driver Class public class GFG { // Main Function public static void main(String[] args) { // Create an ArrayDeque // which contains string values ArrayDeque cities = new ArrayDeque();

    // Add Strings to list
    cities.add("Kolkata");
    cities.add("Delhi");
    cities.add("Bombay");
    cities.add("Pune");

    // forEach method of ArrayDeque and
    // print city names
    cities.forEach((n) -> System.out.println(n));
}

}

`

Output

Kolkata Delhi Bombay Pune

**Example 2:

To demonstrate forEach() method on ArrayDeque which contains queue of Objects.

Java `

// Java Program Demonstrate forEach() // method of ArrayDeque import java.util.*;

// Driver Class public class GFG { // Main Method public static void main(String[] args) { // Create an ArrayDeque which going to // Contains a list of Objects ArrayDeque list = new ArrayDeque();

    // Add Objects to list
    list.add(new batch("CSE", 67));
    list.add(new batch("ECE", 57));
    list.add(new batch("IT", 90));
    list.add(new batch("ME", 78));

    // Print result
    System.out.println("list of Objects:");

    // forEach method of ArrayDeque and
    // Print student names
    list.forEach((n) -> print(n));
}

// Printing details of object
public static void print(batch n)
{
    System.out.println("*******************************");
    System.out.println("Batch Name is " + n.name);
    System.out.println("No of Students are " + n.noOfStudents);
}

}

// Create a Class class batch {

String name;
int noOfStudents;

batch(String name, int noOfStudents)
{
    this.name = name;
    this.noOfStudents = noOfStudents;
}

}

`

Output

list of Objects:

Batch Name is CSE No of Students are 67

Batch Name is ECE No of Students are 57

Batch Name is IT No of Students are 90

Batch Name is ME No of Students are 78

**Example 3:

To demonstrate NullPointerException of forEach() method on ArrayDeque.

Java `

// Java Program Demonstrate forEach() // method of ArrayDeque import java.util.*;

// Driver Class public class GFG { // Main Method public static void main(String[] args) { // Create an ArrayDeque // Which contains string values ArrayDeque cities = new ArrayDeque();

    // Add Strings to list
    cities.add("Kolkata");
    cities.add("Delhi");
    cities.add("Bombay");
    cities.add("Pune");

    try {
        // forEach method of ArrayDeque and
        // print city names
        cities.forEach(null);
    }
    catch (Exception e) {
        System.out.println("Exception: " + e);
    }
}

}

`

Output

Exception: java.lang.NullPointerException