ArrayList isEmpty() Method in Java with Examples
In Java, the isEmpty() method of ArrayList is used to check if an ArrayList is empty.
Example 1: Here, we use the isEmpty() method to check whether an ArrayList of integers is empty.
// Java program to demonstrate the use of isEmpty()
// method with ArrayList of Integers
import java.util.ArrayList;
public class GFG {
public static void main(String[] args) {
// Creating an empty ArrayList of Integers
ArrayList<Integer> n = new ArrayList<>();
// Checking if the ArrayList is empty
boolean res = n.isEmpty();
System.out.println("" + res);
// Adding an element
// to the ArrayList
n.add(21);
// Checking again if the
// ArrayList is empty
res = n.isEmpty();
System.out.println("" + res);
}
}
Output
true false
Syntax of ArrayList isEmpty() Method
public boolean isEmpty()
Return Type: It returns a boolean value, true if the list is empty, otherwise false.
Example 2: Here, we use the isEmpty() method to check if an ArrayList of strings is empty.
// Java program to demonstrate the use of
// isEmpty() method with ArrayList of Strings
import java.util.ArrayList;
public class GFG {
public static void main(String[] args) {
// Creating an ArrayList of Strings
ArrayList<String> s = new ArrayList<>();
// Checking if the ArrayList is empty
System.out.println("" + s.isEmpty());
// Adding an element to
// the ArrayList
s.add("Cherry");
// Checking again if the
// ArrayList is empty
System.out.println("" + s.isEmpty());
}
}
Output
true false
Example 3: Here, we will use the isEmpty() method to check if an ArrayList of Objects is empty.
// Java program to demonstrate the use of
// isEmpty() method with custom Objects
import java.util.ArrayList;
class Person {
String n;
int a;
// Constructor
public Person(String n, int a) {
this.n = n;
this.a = a;
}
}
public class Main {
public static void main(String[] args) {
// create an ArrayList of Person objects
ArrayList<Person> p = new ArrayList<>();
// check if the ArrayList is empty
System.out.println("" + p.isEmpty());
// add a Person object to the ArrayList
p.add(new Person("Sweta", 24));
// check again if the ArrayList is empty
System.out.println("" + p.isEmpty());
}
}
Output
true false