[Term Entry] Java Queue: add() (#7362)

content/java/concepts/queue/terms/add/add.md

@@ -0,0 +1,71 @@
+---
+Title: '.add()'
+Description: 'Inserts an element at the back of the queue.'
+Subjects:
+  - 'Code Foundations'
+  - 'Computer Science'
+Tags: 
+  - 'Collections'
+  - 'Data Structures'
+  - 'Methods'
+  - 'Queues'
+CatalogContent:
+  - 'learn-java'
+  - 'paths/computer-science'
+---
+
+The **`.add()`** method is a built-in method of the [`Queue`](https://www.codecademy.com/resources/docs/java/queue) interface in Java that inserts an element at the back of the `queue`. It returns true if the element is successfully added. Unlike `.offer()`, which returns false if the insertion fails, `.add()` throws an [`Exception`](https://www.codecademy.com/resources/docs/java/errors). This method is commonly used with implementations such as `LinkedList` and `ArrayDeque`.
+
+## Syntax
+
+```pseudo
+queue_name.add(E element);
+```
+
+**Parameters:**
+
+The `.add()` method requires an `element` as a parameter. The `E` is the type of the `element` parameter, which is the type of elements held in the `queue_name` [collection](https://www.codecademy.com/resources/docs/java/collection).
+
+**Return value:**
+
+The `.add()` method returns `true` upon success. If the queue has a capacity limit and is full, `.add()` throws an `IllegalStateException`.
+
+## Example
+
+In this example, a `Queue` in Java is created using `LinkedList`, elements are added to it, and then the `.add()` method is used to insert an additional element at the end of the queue:
+
+```java
+import java.util.*;
+class JAVA {
+  public static void main(String args[]){
+    Queue<Integer> myQueue = new LinkedList<Integer>();
+    myQueue.add(5);
+    myQueue.add(2);
+    myQueue.add(11);
+    myQueue.add(7);
+    myQueue.add(8);
+
+    // myQueue before adding 3: 5 => 2 => 11 => 7 => 8
+    System.out.println("The elements in the queue are: " + myQueue);
+
+    // adding 3 to myQueue
+    boolean success = myQueue.add(3);
+    System.out.println("3 inserted at the back of the queue: " + success);
+
+    // myQueue after adding 3: 5 => 2 => 11 => 7 => 8 => 3
+    System.out.println("The elements in the queue are: " + myQueue);
+  }
+}
+```
+
+The output generated by this code is:
+
+```shell
+The elements in the queue are: [5, 2, 11, 7, 8]
+3 inserted at the back of the queue: true
+The elements in the queue are: [5, 2, 11, 7, 8, 3]
+```
+
+Visual representation of the `.add()` method:
+
+![A diagram showing the addition of an item to a queue. The top row displays a queue with the numbers 5, 2, 11, 7, and 8. Below, the code "queue_name.add(3);" is shown, with an arrow pointing to the end of the queue. The bottom row shows the updated queue: 5, 2, 11, 7, 8, 3, illustrating that the number 3 was added to the end of the queue.](https://raw.githubusercontent.com/Codecademy/docs/main/media/java-queue-add.png)