java.util.ArrayList class

java.util.ArrayList class

java.util.ArrayList class

• We can store group of objects in ArrayList object.
• Here group of objects means, it can allow us to store same type of objects and different type of objects.
• Same type means, assuming that all objects are in the form of integer types.
• Different type means, assuming that all objects are in the form of integer, float, String, Student and Customer types also.
• ArrayList extends AbstractList class which is a abstract class and implements List interface.
• Size will increase dynamically.
• ArrayList is non synchronized.
• We can get the objects in Random order because ArrayList works on index based.

Limitation

• The process of ArrayList is very slow, if you are inserting and removing the objects from middle of the ArrayList.

Inherited features from List

• We will get the output according to insertion order.
• Allows duplicate objects.

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Program         :       Example on ArrayList class

Program name  :       ALDemo1.java

Output            :         

      [1, Nireekshan, A, 1.1, 1.12345]

     

import java.util.ArrayList;
class ALDemo1
{
public static void main(String args[])
{
ArrayList arrayList = new ArrayList();

arrayList.add(1);
arrayList.add("Nireekshan");
arrayList.add('A');
arrayList.add(1.1f);
arrayList.add(1.12345);

System.out.println(arrayList);
}

}

Compile       :         javac ALDemo1.java

Run             :         java ALDemo1

Output        :         

     [1, Nireekshan, A, 1.1, 1.12345]

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Thanks for your time.

- Nireekshan