What does addAll() do in Java?
The addAll() method adds all of the items from a collection to the list. All() method is a static utility function in the java. Collections class. Its primary purpose is to add multiple elements to a collection in one go, rather than adding them individually using a loop.All method in Java isn’t null safe. If you pass a null reference into it, you’ll get a NullPointerException thrown.
How to use addAll?
The addAll() method adds all of the items from a collection to the list. If an index is provided then the new items will be placed at the specified index, pushing all of the following elements in the list ahead. If an index is not provided then the new items will be placed at the end of the list. The add() method adds an item to the list. If an index is provided then the new item will be placed at the specified index, pushing all of the following elements in the list ahead by one.
What is addAll in Apex list?
All(fromList) Adds all of the elements in the specified list to the list that calls the method. Both lists must be of the same type. All(fromSet) Adds all of the elements in the specified set to the list that calls the method. The set and the list must be of the same type. All() method is declared in the Set interface and is implemented in the HashSet class. It is used to add all of the elements in the specified collection to this set if they’re not already present.
What is the addAll method in set?
The . All() method is declared in the Set interface and is implemented in the HashSet class. It is used to add all of the elements in the specified collection to this set if they’re not already present. A LinkedHashSet is a collection that stores unique elements and remembers the order they were added. It is part of the java. Set interface. Tip: Use LinkedHashSet when you want a set that does not allow duplicates and keeps the original insertion order.
Does addAll remove duplicates?
Understand that addAll() does not inherently manage duplicates. Decide on the logic to handle duplicates based on the application needs. Here, a HashSet is used to ensure no duplicates are added, demonstrating how to handle duplicate elements when using addAll() by employing a set that doesn’t allow duplicates. This behavior is enforced by the underlying implementations of the Set interface, such as HashSet, TreeSet, and LinkedHashSet. The main reason Sets do not allow duplicates is due to the contract defined by the Set interface: Uniqueness: Sets are designed to store unique elements only.