Java Number Class Methods with Examples

This article is series of Java Lang Package tutorial. In this tutorial, we will discuss the important and commonly used Number class methods with examples.
The java.lang.Number class is the superclass of classes BigDecimal, BigInteger, Byte, Double, Float, Integer, Long, and Short. The Subclasses of Number must provide methods to convert the represented numeric value to byte, double, float, int, long, and short.
Check out below Java Core API packages tutorials:

Java Number Class Methods

  • byte byteValue() - Returns the value of the specified number as a byte, which may involve rounding or truncation.
  • abstract double doubleValue() - Returns the value of the specified number as a double, which may involve rounding.
  • abstract float floatValue() - Returns the value of the specified number as a float, which may involve rounding.
  • abstract int intValue() - Returns the value of the specified number as an int, which may involve rounding or truncation.
  • abstract long longValue() - Returns the value of the specified number as a long, which may involve rounding or truncation.
  • short shortValue() - Returns the value of the specified number as a short, which may involve rounding or truncation.

Java Number Class Methods/APIs with Examples

byte byteValue()

This method returns the value of the specified number as a byte, which may involve rounding or truncation.
public void byteValueMethod() {
 // get a number as integer
 Number x = new Integer(123456);

 // get a number as float
 Number y = new Float(9876f);

 // print their value as byte
 System.out.println("x as integer:" + x + ", x as byte:" + x.byteValue());
 System.out.println("y as float:" + y + ", y as byte:" + y.byteValue());
}
Output:
x as integer:123456, x as byte:64
y as float:9876.0, y as byte:-108

abstract double doubleValue()

This method returns the value of the specified number as a double, which may involve rounding.
public void doubleValueMethod() {
 // get a number as integer
 Number x = new Integer(123456);

 // get a number as float
 Number y = new Float(9876f);

 // print their value as double
 System.out.println("x as integer :" + x + ", x as double:" + x.doubleValue());
 System.out.println("y as float::" + y + ", y as double:" + y.doubleValue());
}
Output:
x as integer :123456, x as double:123456.0
y as float::9876.0, y as double:9876.0

abstract float floatValue()

This method returns the value of the specified number as a float, which may involve rounding.
public void floatValueMethod() {
 // get a number as integer
 Number x = new Integer(123456);

 // get a number as double
 Number y = new Double(9876);

 // print their value as float
 System.out.println("x as integer:" + x + ", x as float:" + x.floatValue());
 System.out.println("y as double:" + y + ", y as float:" + y.floatValue());
}
Output:
x as integer:123456, x as float:123456.0
y as double:9876.0, y as float:9876.0

abstract int intValue()

This method returns the value of the specified number as an int, which may involve rounding or truncation.
public void intValueMethod() {
 // get a number as float
 Number x = new Float(123456f);

 // get a number as double
 Number y = new Double(9876);

 // print their value as int
 System.out.println("x as float:" + x + ", x as Integer:" + x.intValue());
 System.out.println("y as double:" + y + ", y as Integer:" + y.intValue());
}
Output:
x as float:123456.0, x as Integer:123456
y as double:9876.0, y as Integer:9876

abstract long longValue()

This method returns the value of the specified number as a long, which may involve rounding or truncation.
public void longValueMethod() {
 // get a number as float
 Number x = new Float(123456f);

 // get a number as double
 Number y = new Double(9876);

 // print their value as long
 System.out.println("x as float:" + x + ", x as long:" + x.longValue());
 System.out.println("y as double:" + y + ", y as long:" + y.longValue());
}
Output:
x as float:123456.0, x as long:123456
y as double:9876.0, y as long:9876

short shortValue()

This method returns the value of the specified number as a short, which may involve rounding or truncation.
public void shortValueMethod() {
 // get a number as float
 Number x = new Float(123456f);

 // get a number as double
 Number y = new Double(9876);

 // print their value as short
 System.out.println("x as float :" + x + ", x as short:" + x.shortValue());
 System.out.println("y as double:" + y + ", y as short:" + y.shortValue());
}
Output:
x as float :123456.0, x as short:-7616
y as double:9876.0, y as short:9876

Complete Example

package net.javaguides.lang;

/**
 * Class demonstrates the usage of Random class methods with examples
 * 
 * @author Ramesh Fadatare
 *
 */
public class NumberClassMethods {

    public static void main(String[] args) {
        NumberClassMethods classMethods = new NumberClassMethods();
        classMethods.shortValueMethod();
        classMethods.longValueMethod();
        classMethods.intValueMethod();
        classMethods.floatValueMethod();
        classMethods.doubleValueMethod();
        classMethods.byteValueMethod();
    }

    public void shortValueMethod() {
        // get a number as float
        Number x = new Float(123456 f);

        // get a number as double
        Number y = new Double(9876);

        // print their value as short
        System.out.println("x as float :" + x + ", x as short:" + x.shortValue());
        System.out.println("y as double:" + y + ", y as short:" + y.shortValue());
    }

    public void longValueMethod() {
        // get a number as float
        Number x = new Float(123456 f);

        // get a number as double
        Number y = new Double(9876);

        // print their value as long
        System.out.println("x as float:" + x + ", x as long:" + x.longValue());
        System.out.println("y as double:" + y + ", y as long:" + y.longValue());
    }

    public void intValueMethod() {
        // get a number as float
        Number x = new Float(123456 f);

        // get a number as double
        Number y = new Double(9876);

        // print their value as int
        System.out.println("x as float:" + x + ", x as Integer:" + x.intValue());
        System.out.println("y as double:" + y + ", y as Integer:" + y.intValue());
    }

    public void floatValueMethod() {
        // get a number as integer
        Number x = new Integer(123456);

        // get a number as double
        Number y = new Double(9876);

        // print their value as float
        System.out.println("x as integer:" + x + ", x as float:" + x.floatValue());
        System.out.println("y as double:" + y + ", y as float:" + y.floatValue());
    }

    public void doubleValueMethod() {
        // get a number as integer
        Number x = new Integer(123456);

        // get a number as float
        Number y = new Float(9876 f);

        // print their value as double
        System.out.println("x as integer :" + x + ", x as double:" + x.doubleValue());
        System.out.println("y as float::" + y + ", y as double:" + y.doubleValue());
    }

    public void byteValueMethod() {
        // get a number as integer
        Number x = new Integer(123456);

        // get a number as float
        Number y = new Float(9876 f);

        // print their value as byte
        System.out.println("x as integer:" + x + ", x as byte:" + x.byteValue());
        System.out.println("y as float:" + y + ", y as byte:" + y.byteValue());
    }

}
Output:
x as float :123456.0, x as short:-7616
y as double:9876.0, y as short:9876
x as float:123456.0, x as long:123456
y as double:9876.0, y as long:9876
x as float:123456.0, x as Integer:123456
y as double:9876.0, y as Integer:9876
x as integer:123456, x as float:123456.0
y as double:9876.0, y as float:9876.0
x as integer :123456, x as double:123456.0
y as float::9876.0, y as double:9876.0
x as integer:123456, x as byte:64
y as float:9876.0, y as byte:-108

References

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