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Ace the AP Computer Science Exam for High Schoolers

Java Wrapper Class: Double

Get a brief introduction to Double, a Java wrapper class.

We'll cover the following...

Introducing Double

The Double class is part of the java.lang package.

The Double class is a wrapper class for the primitive type double. It contains several methods to deal with double type values effectively. An object of Double class can hold a single double value.

Creating a Double object

This class has two constructors:

  • Double (double value)
  • Double (String string)

Let’s cover them one by one.

The Double (double value) constructor

This constructor constructs a new Double object that represents the specified double value.

Look at the program below.

Java
class DoubleWrapperDemo1 
{
    public static void main(String args[]) 
    {
        Double x = new Double(5); // Creating an Double type object
        System.out.println(x);
    }
}

Look at line 5. We create the Double object, called x. We pass 55 as the argument. Now, when we try to print x, we get 5.05.0 as a result. It behaves just like a standard double ...