
- Java.util - Home
- Java.util - ArrayDeque
- Java.util - ArrayList
- Java.util - Arrays
- Java.util - BitSet
- Java.util - Calendar
- Java.util - Collections
- Java.util - Currency
- Java.util - Date
- Java.util - Dictionary
- Java.util - EnumMap
- Java.util - EnumSet
- Java.util - Formatter
- Java.util - GregorianCalendar
- Java.util - HashMap
- Java.util - HashSet
- Java.util - Hashtable
- Java.util - IdentityHashMap
- Java.util - LinkedHashMap
- Java.util - LinkedHashSet
- Java.util - LinkedList
- Java.util - ListResourceBundle
- Java.util - Locale
- Java.util - Observable
- Java.util - PriorityQueue
- Java.util - Properties
- Java.util - PropertyPermission
- Java.util - PropertyResourceBundle
- Java.util - Random
- Java.util - ResourceBundle
- Java.util - ResourceBundle.Control
- Java.util - Scanner
- Java.util - ServiceLoader
- Java.util - SimpleTimeZone
- Java.util - Stack
- Java.util - StringTokenizer
- Java.util - Timer
- Java.util - TimerTask
- Java.util - TimeZone
- Java.util - TreeMap
- Java.util - TreeSet
- Java.util - UUID
- Java.util - Vector
- Java.util - WeakHashMap
- Java.util - Interfaces
- Java.util - Exceptions
- Java.util - Enumerations
- Java.util Useful Resources
- Java.util - Useful Resources
- Java.util - Discussion
Java ArrayList size() Method
Description
The Java ArrayList size() method returns the number of elements in this list i.e the size of the list. It is updated everytime a change is made to the ArrayList.
Declaration
Following is the declaration for java.util.ArrayList.size() method
public int size()
Parameters
NA
Return Value
This method returns the number of elements in this list.
Exception
NA
Getting Size of an ArrayList of Integers Example
The following example shows the usage of Java ArrayList size() method. We're adding couple of Integers to the ArrayList object using add() method calls per element. Size of the arraylist is printed using size() method. And using remove(index) method, we're removing one element and size of the arraylist is again printed.
package com.tutorialspoint; import java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { // create an empty array list ArrayList<Integer> arrayList = new ArrayList<>(); // use add() method to add elements in the arrayList arrayList.add(20); arrayList.add(30); arrayList.add(20); arrayList.add(30); arrayList.add(15); arrayList.add(22); arrayList.add(11); // let us print the size of the arrayList again System.out.println("Arraylist Size = " + arrayList.size()); // remove an element at index 2 arrayList.remove(2); // let us print the size of the arrayList again System.out.println("Arraylist Size = " + arrayList.size()); } }
Output
Let us compile and run the above program, this will produce the following result −
Arraylist Size = 7 Arraylist Size = 6
Getting Size of an ArrayList of Strings Example
The following example shows the usage of Java ArrayList size() method. We're adding couple of Strings to the ArrayList object using add() method calls per element. Size of the arraylist is printed using size() method. And using remove(index) method, we're removing one element and size of the arraylist is again printed.
package com.tutorialspoint; import java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { // create an empty array list ArrayList<String> arrayList = new ArrayList<>(); // use add() method to add elements in the arrayList arrayList.add("Welcome"); arrayList.add("To"); arrayList.add("Tutorialspoint"); // let us print the size of the arrayList again System.out.println("Arraylist Size = " + arrayList.size()); // remove an element at index 2 arrayList.remove(2); // let us print the size of the arrayList again System.out.println("Arraylist Size = " + arrayList.size()); } }
Output
Let us compile and run the above program, this will produce the following result −
Arraylist Size = 3 Arraylist Size = 2
Getting Size of an ArrayList of Objects Example
The following example shows the usage of Java ArrayList size() method. We're adding couple of Student objects to the ArrayList object using add() method calls per element. Size of the arraylist is printed using size() method. And using remove(index) method, we're removing one element and size of the arraylist is again printed.
package com.tutorialspoint; import java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { // create an empty arrayList ArrayList<Student> arrayList = new ArrayList<>(); // use add() method to add elements in the arrayList arrayList.add(new Student(1, "Julie")); arrayList.add(new Student(2, "Robert")); arrayList.add(new Student(3, "Adam")); // let us print the size of the arrayList again System.out.println("Arraylist Size = " + arrayList.size()); // remove an element at index 2 arrayList.remove(2); // let us print the size of the arrayList again System.out.println("Arraylist Size = " + arrayList.size()); } } class Student { int rollNo; String name; Student(int rollNo, String name){ this.rollNo = rollNo; this.name = name; } @Override public String toString() { return "[ " + this.rollNo + ", " + this.name + " ]"; } }
Output
Let us compile and run the above program, this will produce the following result −
Arraylist Size = 3 Arraylist Size = 2