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Java - Double class

Introduction

The Java Double class wraps a value of primitive type double in an object. An object of type Double contains a single field whose type is double.

Class Declaration

Following is the declaration for java.lang.Double class −

public final class Double
   extends Number
      implements Comparable<Double>

Field

Following are the fields for java.lang.Double class −

  • static int MAX_EXPONENT − This is the maximum exponent a finite double variable may have.

  • static double MAX_VALUE − This is the constant holding the largest positive finite value of type double, (2-2-52)×21023.

  • static int MIN_EXPONENT − This is the minimum exponent a normalized double variable may have.

  • static double MIN_NORMAL − This is the constant holding the smallest positive normal value of type double, 2-1022.

  • static double MIN_VALUE − This is the constant holding the smallest positive nonzero value of type double, 2-1074.

  • static double NaN − This is the constant holding a Not-a-Number (NaN) value of type double.

  • static double NEGATIVE_INFINITY − This is the constant holding the negative infinity of type double.

  • static double POSITIVE_INFINITY − This is the constant holding the positive infinity of type double.

  • static int SIZE − This is the number of bits used to represent a double value.

  • static Class<Double> TYPE − This is the class instance representing the primitive type double

Class constructors

Sr.No. Constructor & Description
1

Double(double value)

This constructs a newly allocated Double object that represents the primitive double argument.
2

Double(String s)

This constructs a newly allocated Double object that represents the floating-point value of type double represented by the string.

Class methods

Methods inherited

This class inherits methods from the following classes −

  • java.lang.Object

Example

The following example shows the usage of Double class to get double from a string. We've created a String and then using valueOf() method, we're retrieving getting a Double Object and then double object is printed.

package com.tutorialspoint;

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

      // create a String s and assign value to it
      String s = "+120";

      // create a Double object b
      Double b;

      // get the value of double from string
      b = Double.valueOf(s);

      // print b value
      System.out.println( "Double value of string " + s + " is " + b );
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Double value of string +120 is 120.0