OptionalDouble orElseThrow() method in Java with examples

OptionalDouble help us to create an object which may or may not contain a Double value. The orElseThrow() method help us to get the double value. If double value is not present then this method will throw NoSuchElementException. Syntax:

public Double orElseThrow()

Parameters: This method accepts nothing. Return value: This method returns the Double value described by this OptionalDouble. Exception: This method throws NoSuchElementException if no value is present Below programs illustrate orElseThrow() method: Program 1:

Java

// Java program to demonstrate
// OptionalDouble.orElseThrow() method

import java.util.OptionalDouble;

public class GFG {

    public static void main(String[] args)
    {

        // create a OptionalDouble
        OptionalDouble opDouble
            = OptionalDouble.of(134.1);

        // get value using orElseThrow()
        System.out.println("double Value extracted using"
                           + " orElseThrow() = "
                           + opDouble.orElseThrow());
    }
}

Output:

double Value extracted using orElseThrow() = 134.1

Program 2:

Java

// Java program to demonstrate
// OptionalDouble.orElseThrow() method

import java.util.OptionalDouble;

public class GFG {

    public static void main(String[] args)
    {

        // create a OptionalDouble
        OptionalDouble opDouble
            = OptionalDouble.empty();

        try {

            // try to get value from empty OptionalDouble
            Double value = opDouble.orElseThrow();
        }
        catch (Exception e) {

            System.out.println("Exception thrown : "
                               + e);
        }
    }
}

Output:

Exception thrown : java.util.NoSuchElementException: No value present

References: https://docs.oracle.com/javase/10/docs/api/java/util/OptionalDouble.html#orElseThrow()