Optional ofNullable() method in Java with examples

The ofNullable() method of the Optional class creates an Optional containing the specified value when it is non-null. If the value is null, it returns an empty Optional instead.

• It is useful when a value might be null and needs to be represented using Optional.
• Unlike Optional.of(), ofNullable() handles both non-null and null values without throwing a NullPointerException.

Example: Program to demonstrate how ofNullable() creates an Optional for a non-null value.

import java.util.Optional;

public class GFG {
    public static void main(String[] args) {

        String value = "GeeksforGeeks";

        Optional<String> result = Optional.ofNullable(value);

        System.out.println(result);
    }
}

Optional[GeeksforGeeks]

Explanation: The value variable contains a non-null string, so Optional.ofNullable() creates an Optional containing that value. If value were null, the method would return Optional.empty() instead.

Syntax:

public static <T> Optional<T> ofNullable(T value)

The method returns an Optional containing the specified value. For a null value, it returns an empty Optional.

Working of ofNullable()

ofNullable() checks the supplied value and creates an Optional containing the value when it is non-null or returns an empty Optional when it is null.

• Provide Value: A value is passed to ofNullable().
• Check Value: The method checks whether the value is null.
• Non-Null Value: If the value is not null, an Optional containing that value is returned.
• Null Value: If the value is null, Optional.empty() is returned.

Using ofNullable() with Different Values

The ofNullable() method handles both non-null and null values by creating an Optional containing the value or returning an empty Optional, respectively.

1: Using ofNullable() with a Non-Null Value

The following program passes an integer value to ofNullable(). The value is stored inside the Optional object.

import java.util.*;

public class GFG {
    public static void main(String[] args) {

        Optional<Integer> op1 =
            Optional.ofNullable(9455);

        System.out.println("Optional 1: " + op1);
    }
}

Optional 1: Optional[9455]

Explanation: The value 9455 is not null, so ofNullable() creates an Optional containing that value. Printing the object displays Optional[9455].

 2: Using ofNullable() with a Null Value

The following program passes null to ofNullable().

import java.util.*;

public class GFG {
    public static void main(String[] args) {

        Optional<String> op2 =
            Optional.ofNullable(null);

        System.out.println("Optional 2: " + op2);
    }
}

Optional 2: Optional.empty

Explanation: Since the specified value is null, ofNullable() returns an empty Optional. The empty instance is displayed as Optional.empty.

3: Using ofNullable() with a Variable

ofNullable() is particularly useful when a variable receives its value from a method, database, collection, or another source where the value might be null.

import java.util.Optional;

public class GFG {
    public static void main(String[] args) {

        String name = null;

        Optional<String> result = Optional.ofNullable(name);

        System.out.println(result);
    }
}

Optional.empty

Explanation: The name variable contains null, so ofNullable() returns an empty Optional instead of throwing an exception.

4: Using ofNullable() with Method Return Value

ofNullable() is also useful when a method might return null. Instead of directly working with the returned value, the result is wrapped in an Optional.

import java.util.Optional;

public class GFG {

    static String getName() {
        return null;
    }

    public static void main(String[] args) {

        Optional<String> name = Optional.ofNullable(getName());

        System.out.println(name);
    }
}

Optional.empty

Explanation: The getName() method returns null. ofNullable() converts this null result into Optional.empty(), providing an explicit representation of the absence of a value.

ofNullable() vs of()

The main difference between ofNullable() and of() is how they handle null values.