Does ArrayList extend AbstractList?

The ArrayList class extends AbstractList and implements the List interface. Unlike a conventional array, ArrayList is dynamic so that it can grow as needed. When an ArrayList’s size is exceeded, the collection automatically enlarges.

What does it mean for a list to be dynamic in ArrayList?

An ArrayList is a re-sizable array, also called a dynamic array. It grows its size to accommodate new elements and shrinks the size when the elements are removed. ArrayList internally uses an array to store the elements.

What happens when you add to ArrayList?

add(int index, E elemen) method inserts the specified element E at the specified position in this list.It shifts the element currently at that position (if any) and any subsequent elements to the right (will add one to their indices).

What is the use of AbstractList?

In Java, the Abstract List is the part of the Java Collection Framework. The Abstract list is implemented by the collection interface and the Abstract Collection class. This is used when the list can not be modified. To implement this AbstractList class is used with get() and size() methods.

Which extends the AbstractList class and implements list?

ArrayList
ArrayList implements List as well as extends AbstractList .

Which class extends the AbstractList class and implements the interfaces?

The AbstractList class in Java is a part of the Java Collection Framework and implements the Collection interface and the AbstractCollection class. It is used to implement an unmodifiable list, for which one needs to only extend this AbstractList Class and implement only the get() and the size() methods.

Does ArrayList extend list?

The ArrayList class extends AbstractList and implements the List interface. ArrayList supports dynamic arrays that can grow as needed. Standard Java arrays are of a fixed length. Following is the list of the constructors provided by the ArrayList class.

Does ArrayList maintain insertion order?

Yes, ArrayList is an ordered collection and it maintains the insertion order.

Which method adds an element to an ArrayList?

ArrayList add() method
ArrayList add() method is used to add an element in the list.

What extends the AbstractList class?

How does ArrayList increase in size?

The ArrayList size increases dynamically because whenever the ArrayList class requires to resize then it will create a new array of bigger size and copies all the elements from the old array to the new array. And now it is using the new array’s reference for its internal usage.

Can’t We say that ArrayList implements List?

If ArrayList extends AbstractList and AbstractList implements List, can’t we say, that ArrayList implement List? Yes. It could’ve been omitted. But thus it is immediately visible that it is a List. Otherwise an extra click through the code / documentation would be required.

Is it redundant to implement list as well as extend abstractlist?

The implementation of java.util.ArrayList implements List as well as extends AbstractList. But in java docs you can see that AbstractList already implements List. Then wouldn’t it be redundant to implement List as well as extend AbstractList? The Arrays.asList () method of the Arrays class contains its own implementation of ArrayList.

What is the purpose of abstractlist in Java?

And to add what Joeri Hendrickx commented – it is for the purpose of showing that ArrayList implements List. AbstractList in the whole picture is just for convenience and to reduce code duplication between List implementations. My 2 cents is to keep to the fact that ArrayList is a List.

Why ArrayList failed to be converted to list?

Note that Arrays.ArrayList class is not publicly visible, so its authors did not care to include List explicitly. As far as the failed conversion goes, this should come as no surprise, because the inner class Arrays.ArrayList and the public class ArrayList are unrelated to each other.