How to find length/size of ArrayList in Java? Example

You can use the size() method of java.util.ArrayList to find the length or size of ArrayList in Java. The size() method returns an integer equal to a number of elements present in the array list. It's different than the length of the array which is backing the ArrayList, that is called the capacity of ArrayList. When you create an object of ArrayList in Java without specifying a capacity, it is created with a default capacity which is 10. Since ArrayList is a growable array, it automatically resizes when the size (number of elements in array list) grows beyond a threshold. Also, when an ArrayList is first created it is called empty ArrayList and size() will return zero. If you add elements then size grows one by one. You can also remove all elements from ArrayList by using a clear() method which will then again make the ArrayList empty as shown in our examples.

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