( ** Java Certification Training: https://www.edureka.co/java-j2ee-soa-training ** ) This Edureka tutorial on “Java ArrayList” (Java blog series: https://goo.gl/osrGrS) will give you a brief insight about ArrayList in Java and its various constructors and methods along with an example. Through this tutorial, you will learn the following topics: Collections Framework Hierarchy of ArrayList What is ArrayList Internal Working of ArrayList Constructors of ArrayList Constructors Example ArrayList Methods Methods Example and Demo Advantages of ArrayList over Arrays Check out our Java Tutorial blog series: https://goo.gl/osrGrS Check out our complete Youtube playlist here: https://goo.gl/CRbgFann Follow us to never miss an update in the future. Instagram: https://www.instagram.com/edureka_learning/ Facebook: https://www.facebook.com/edurekaIN/ Twitter: https://twitter.com/edurekain LinkedIn: https://www.linkedin.com/company/edureka

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01 Collections Framework
02 Hierarchy of ArrayList Class
03 ArrayList in Java
04 Internal Working of ArrayList
05 Constructors of ArrayList
06 Methods of ArrayList
07 Benefits of ArrayList vs Arrays
Topics For Today’s Discussion

3. Collections Framework

4. Collection
SortedSet
SetList
Priority Queue
ArrayDeque
TreeSet
LinkedHashSet
HashSet
Iterable
Queue
ArrayList
LinkedList
Vector
Stack
Deque

5. ArrayList
Collection
List
Abstract List
Hierarchy of Array List Class
Iterable
extends
implements
extends
extends

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ArrayList in Java
ArrayList is a part of collection framework present in java.util package. It provides dynamic arrays in Java.

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Internal Working of ArrayList
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
Array List Initialization
Adding elements to Array List
Capacity of Array List is Full
Creating a new array & moving the
elements to new array
Size is increased to double

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Constructors of ArrayList
ArrayList(int Capacity)
ArrayList(Collection c)
ArrayList( )

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Constructors of ArrayList
ArrayList(int Capacity)
ArrayList(Collection c)
ArrayList( ) This constructor builds an empty array list.
Syntax:
ArrayList<E> myArray = new ArrayList<E>();

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Constructors of ArrayList
ArrayList(int Capacity)
ArrayList( )
ArrayList(Collection c)
This constructor builds an array list that is initialized with the
elements of the collection c.
public boolean addAll(Collection c)
Syntax:

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Constructors of ArrayList
ArrayList(Collection c)
ArrayList( )
ArrayList(int Capacity)
It is used to build an array list that has the specified initial capacity.
ArrayList myArray = new ArrayList(int
initialCapacity);
Syntax:

12. Methods of Arraylist

13. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
This method is used to insert a specific element at a specific position
index in a list.
ArrayList<String> al=new ArrayList<String>();
al.add(“Jino");
al.add(“Piyush");
al.add(“Pramod");
Example:

14. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
This method is used to remove all the elements from any list.
ArrayList<String> al=new ArrayList<String>();
al.add("abc");
al.add("xyz");
System.out.println("ArrayList before clear: "+al);
al.clear();
System.out.println("ArrayList after clear: "+al);
Example:

15. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
ArrayList<Integer> al = new ArrayList<Integer>(9);
al.add(2);
al.add(4);
al.add(5);
al.trimToSize();
System.out.println("The List elements are:");
The trimToSize() method in Java trims the capacity of an ArrayList instance
to be the list’s current size. This method is used to trim an ArrayList
instance to the number of elements it contains.
Example:

16. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
ArrayList<Integer> al = new ArrayList<Integer>(9);
al.add(2);
al.add(4);
al.add(5);
int pos = al. indexOf(3);
This method returns the index of the first occurrence of the specified
element in this list, or -1 if this list does not contain the element.
Example:

17. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
ArrayList<String> al=new ArrayList<String>();
Object cloneList; //Added 2 elements
al.add("abc");
al.add("xyz");
System.out.println("Elements are: ");
cloneList = al.clone();
System.out.println("Elements in cloneList are:");
Returns a shallow copy of this ArrayList.
Example:

18. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
arrayList.add("element_1");
arrayList.add("element_2");
arrayList.add("element_3");
arrayList.add("element_4");
Object[] objArray = arrayList.toArray();
Returns an array containing all of the elements in this list in the correct
order; the runtime type of the returned array is that of the specified
array.
Example:

19. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
arrayList.add(“J");
arrayList.add(“I");
arrayList.add(“N");
arrayList.add(“O");
arraylist.remove(“N”);
Example:
java.util.ArrayList.remove(Object) method removes the first occurrence
of the specified element from this list, if it is present. If the list does not
contain the element, it is unchanged.

20. void add(int index, Object element)
void clear( )
void trimToSize()
Int indexOf(Object O)
Object clone()
Object[] to Array()
Object remove(int index)
Int size()
Declaration: public int size()
arrayList.add(“J");
arrayList.add(“I");
arrayList.add(“N");
arrayList.add(“O");
int asize = arraylist.size();
It returns the number of elements in this list i.e the size of the list.
Example:

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Advantages of ArrayList Over Array
Allows to add duplicate elements
Can traverse in both directions
Insert & Remove elements at particular
position
ArrayList is Variable length
Size can be modified dynamically
Can add any type of data in arraylist