Introduction to ArrayList

Basics of ArrayList

An ArrayList offers a dynamic data structure, where the size can change as needed, unlike regular arrays in Java.
Arraylists belong to the java.util package and therefore, this package needs to be imported for using ArrayLists.
An ArrayList can store elements of a specific type, similar to arrays. However, it allows for greater flexibility in terms of manipulation of data.
In ArrayLists, the indices start at 0, as with arrays.

Declaration and Initialisation of an ArrayList

ArrayList in Java is declared: ArrayList<DataType> listName = new ArrayList<>();.
DataType can be any Object data type like Integer, String, Double etc.
Instances of ArrayLists are initialised by calling the constructor with new ArrayList<>().
Preliminary values can be added during initialisation using Arrays.asList(): ArrayList<Integer> list = new ArrayList<>(Arrays.asList(1,2,3,4));.

Manipulating Elements in an ArrayList

The add(element) function is used for appending elements at the end of the ArrayList.
For insertion of elements at specific indices, add(index, element) is used.
To access elements, get(index) is employed.
The remove(index) function allows for deletion of elements from a given index.
The entire ArrayList can be emptied by calling clear().

Additional Methods for ArrayList Handling

The size() function returns the total number of elements present.
isEmpty() is used to check if an ArrayList is devoid of elements, returning true if so, and false otherwise.
To search for an element’s presence, contains(object) is used, where a true value indicates the object is in the list.
The toArray() function allows for conversion of the ArrayList to an array.

Remember to always import java.util.ArrayList and possibly java.util.Arrays when manipulating ArrayLists in Java programs.