Java Long doubleValue Method

Introduction

In this lab, you will learn how to use the doubleValue() method of the Long class in Java. This method is used to convert a Long object into its equivalent double value. You will see two examples in this lab that demonstrate how to use this method and how to get its output.

Create a Java file

Firstly, open any text editor or an integrated development environment (IDE) of your choice and create a new Java file with the name LongDoubleValue.java in the project folder:

cd ~/project
touch LongDoubleValue.java

Write the Java code

In this step, we will write Java code to demonstrate the usage of the doubleValue() method.

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

        // Example 1
        Long x = 99L;
        double i = x.doubleValue();
        System.out.println(i);

        Long y = 23L;
        double d = y.doubleValue();
        System.out.println(d);

        // Example 2
        System.out.print("Enter the value to be converted : ");

        try {
            Scanner sc = new Scanner(System.in);
            long number = sc.nextLong();
            Long n = number;
            double val = n.doubleValue();

            System.out.println("Double Value is: " + val);
        } catch(Exception e) {
            System.out.println("Not a valid long");
        }
    }
}

Compile and run the code

After writing the code, you need to compile the Java file using the javac command:

javac LongDoubleValue.java

Once the compilation is successful, you can run the code using the java command:

java LongDoubleValue

Output:

99.0
23.0
Enter the value to be converted : 63
Double Value is: 63.0

Test the code

In the second example, you can input any long value and get its double equivalent. For example:

Enter the value to be converted : 456
Double Value is: 456.0

Enter the value to be converted : -789
Double Value is: -789.0

Summary

In this lab, you learned about the doubleValue() method of the Long class in Java. You saw how to create a Java file, write the code, compile, run, and test it. Now, you can easily use the doubleValue() method to convert a Long object into its equivalent double value.