Arraylist – In Java
import java.util.ArrayList;
public class Program1 {
public static void main(String[] args) {
ArrayList<String> countries = new ArrayList<String>();
countries.add("India");
countries.add("USA");
countries.add("China");
countries.add("Russia");
System.out.println(countries);
}
}
🧾 Output:
[India, USA, China, Russia]
💡 What is an ArrayList?
A resizable array in Java (from
java.utilpackage).Can store a list of objects (in this case, Strings).
Allows dynamic addition, removal, and retrieval of items.
🧠 Common Operations:
| Operation | Example Code |
|---|---|
| Add an element | countries.add("Japan"); |
| Get an element by index | countries.get(0); // India |
| Set (replace) an element | countries.set(1, "UK"); |
| Remove an element | countries.remove("China"); |
| Size of the list | countries.size(); |
| Loop through elements (for-each) | for(String c : countries) {} |