Set addAll() Method in Java

In Java, the addAll() method of the Set class is used to add all the elements of a specified collection to the current collection. The elements are added randomly without following any specific order.

Example 1: This example demonstrates how to merge two TreeSet using the addAll() method.

Initial Set: [A, B, C]
Final Set: [A, B, C, D, E]

Syntax of addAll() Method

boolean addAll(Collection<? extends E> c)

• Parameter: The method takes a collection as an argument, which can be any subclass of the Collection interface.
• Return Type: This method returns "true" if the element were added successfully, otherwise returns "false".

Example 2: This example demonstrates how to append elements from an ArrayList to a TreeSet using the addAll() method.