JAVA ArrayList Constructors

JAVA ArrayList Constructors

java.lang.Object

     java.util.AbstractCollection

                 java.util.AbstractList

                          java.util.ArrayList

public class ArrayList

extends AbstractList

implements List, RandomAccess, Cloneable, Serializable

1.    ArrayList() : Create an empty ArrayList object with default initial capacity 10. Once ArrayList reaches its max capacity then new ArrayList will be created with a new capacity.

new capacity=(current capacity*3/2)+1
i.e (10*3/2)+1=16 
after this new ArrayList is created the previous one will be deleted and it will be treated as garbage.

2.    ArrayList(int initialcapacity) : Constructs an empty ArrayList with the specified initial capacity given by the user.

3.    ArrayList(Collection c) : For every Collection object, we can create an equivalent ArrayList.

ArrayListExample1.java

importjava.util.*;
classArrayListExample1
{
    public static void main(String[] args)
    {
            ArrayList al=new ArrayList();
            al.add("Sashi");
            al.add("Satyajit");
            al.add(20);
            al.add(null);
            System.out.println(al);          //[Sashi,Satyajit,20,null]
            al.remove(1);
           al.add(1,"Sasmita");
           al.add("Nilan");
           System.out.println(al);           //[Sashi,Sasmita,20,null,Nilan]
      }
}

Output

[Sashi,Satyajit,20,null]

[Sashi,Sasmita,20,null,Nilan]

Thanks & Regards:

Trilochan Tarai

SILAN Technology

java8s.com

0674-2361252