Java11 - Optional isEmpty

Java11 introduced isEmpty method java.util.Optional package.

Optional is a container object that contains values or null.

It checks if an object does not exist and returns true.

Before java11, We have a isPresent() method in Optional Class

isPresent() is used to check an object that exists in Container and return true.

This only checks for Object that exists in Optional.

If you want to check object does not exist, you have to use a negative condition such as!Optional.isPresent in conditional statements. This is not readable and complex to understand. For example, To check string contains a null value, we have to write the below program.

package java11;

import java.util.Optional;

public class OptionalIsEmptyTest {
    public static void main(String[] args) {
        String name= "john";
        String department= null;

        System.out.println(Optional.ofNullable(name).isPresent());  // true
        System.out.println(Optional.ofNullable(department).isPresent());  //false
        System.out.println(Optional.ofNullable(name).isEmpty());  //false
        System.out.println(Optional.ofNullable(department).isEmpty());  //true
        // Check for department is null
        if(!Optional.ofNullable(department).isPresent()){
            System.out.println("Department is null");
        }
        // Check for name is not null
        if(Optional.ofNullable(name).isPresent()){
            System.out.println("Name is not null");
        }
    }
}

Output:

true
false
Department is null
Name is not null

For negative conditions, you have to use isPresent with operator !.

The isEmpty method is the opposite of the isPresent method in java11.

Java11 Optional isEmpty method

isEmpty method returns true if the value is null, else returns true.

Syntax:

    public boolean isEmpty()

Here is a complete code example for the Optional isEmpty method

package java11;

import java.util.Optional;

public class OptionalIsEmptyTest {
    public static void main(String[] args) {
        String name= "john";
        String department= null;

        System.out.println(Optional.ofNullable(name).isPresent());  // true
        System.out.println(Optional.ofNullable(department).isPresent());  //false
        System.out.println(Optional.ofNullable(name).isEmpty());  //false
        System.out.println(Optional.ofNullable(department).isEmpty());  //true
        // Check for department is null
        if(Optional.ofNullable(department).isEmpty()){
            System.out.println("Department is null");
        }
        // Check for name is not null
        if(!Optional.ofNullable(name).isEmpty()){
            System.out.println("Name is not null");
        }
    }
}