Java Deque removeFirst() Method

The removeFirst() method of Deque interface is used to retrieve and removes the first element of the given deque. The above method is different from the pollFirst() method such that it throws an exception if the given deque is empty.

Syntax:

Parameter:

Return:

The above method is used to return the head of the given deque.

Throw:

NoSuchElementException- If the given deque is empty.

Example 1

import java.util.ArrayDeque;
import java.util.Deque;
public class JavaDequeremoveFirstExample1 {
   public static void main(String[] args) {
	Deque<String> deque = new ArrayDeque<>();
	 deque.offer("Welcome");
	 deque.offer("to");
	 deque.offer("our");
	 deque.offer("site"); 
	   String val = deque.removeFirst();
	   System.out.println("The removed string is : "+val);
      System.out.println("The resultant deque is : ");
      for (String string : deque) {
		System.out.println(string);
	}
   }
}

Test it Now

Output:

The removed string is : Welcome
The resultant deque is : 
to
our
site

Example 2

import java.util.ArrayDeque;
import java.util.Deque;
public class JavaDequeremoveFirstExample2 {
   public static void main(String[] args) {
	Deque<Integer> deque = new ArrayDeque<>();
	 deque.offer(66);
	 deque.offer(11);
	 deque.offer(33);
	 deque.offer(44); 
	  int val = deque.removeFirst();
	   System.out.println("The removed integer value is : "+val);
      System.out.println("The resultant deque is : ");
      for (Integer integer : deque) {
		System.out.println(integer);
	     }
    }
}

Test it Now

Output:

The removed integer value is : 66
The resultant deque is : 
11
33
44

Example 3

import java.util.ArrayDeque;
import java.util.Deque;
public class JavaDequeremoveFirstExample3 {
   public static void main(String[] args) {
	Deque<Long> deque = new ArrayDeque<>();
	 deque.offer(11l);
	 deque.offer(88l);
	 deque.offer(22l);
	 deque.offer(99l); 
	  Long val = deque.removeFirst();
	   System.out.println("The removed long value is : "+val);
      System.out.println("The resultant deque is : ");
      for (Long long1 : deque) {
		System.out.println(long1);
	   }
    }
}

Test it Now

Output:

The removed long value is : 11
The resultant deque is : 
88
22
99

Next TopicJava Deque

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