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Java : Number with Examples

December 31, 2023 March 22, 2022

Number (Java SE 19 & JDK 19) API Examples.
You will find code examples on most Number methods.


Summary

The abstract class Number is the superclass of platform classes representing numeric values that are convertible to the primitive types byte, double, float, int, long, and short.

Number (Java SE 19 & JDK 19)

Class diagram

final Number num = Integer.valueOf(100);

System.out.println(num.intValue()); // 100
System.out.println(num.longValue()); // 100
System.out.println(num.doubleValue()); // 100.0

Constructors

Number ()

Constructor for subclasses to call.

Number (Java SE 19 & JDK 19)

I think it's rare to create a subclass of Number. Therefore, the code example is omitted.

Methods

byte byteValue ()

Returns the value of the specified number as a byte.

Number (Java SE 19 & JDK 19) 
final Number num1 = Byte.valueOf((byte) 0);
System.out.println(num1.byteValue()); // 0

final Number num2 = Byte.valueOf((byte) 100);
System.out.println(num2.byteValue()); // 100

final Number num3 = Byte.valueOf(Byte.MAX_VALUE);
System.out.println(num3.byteValue()); // 127

final Number num4 = Byte.valueOf(Byte.MIN_VALUE);
System.out.println(num4.byteValue()); // -128

final Number num1 = Integer.valueOf(127);
System.out.println(num1.byteValue()); // 127

final Number num2 = Integer.valueOf(128);
System.out.println(num2.byteValue()); // -128

final Number num3 = Integer.valueOf(129);
System.out.println(num3.byteValue()); // -127

final Number num1 = Integer.valueOf(-128);
System.out.println(num1.byteValue()); // -128

final Number num2 = Integer.valueOf(-129);
System.out.println(num2.byteValue()); // 127

final Number num3 = Integer.valueOf(-130);
System.out.println(num3.byteValue()); // 126

final Number num1 = Double.valueOf(1.2345);
System.out.println(num1.byteValue()); // 1

final Number num2 = Double.valueOf(2.9);
System.out.println(num2.byteValue()); // 2

final Number num3 = Double.valueOf(-3.7);
System.out.println(num3.byteValue()); // -3

final Number num1 = Double.valueOf(Double.POSITIVE_INFINITY);
System.out.println(num1.byteValue()); // -1

final Number num2 = Double.valueOf(Double.NEGATIVE_INFINITY);
System.out.println(num2.byteValue()); // 0

final Number num3 = Double.valueOf(Double.NaN);
System.out.println(num3.byteValue()); // 0

abstract double doubleValue ()

Returns the value of the specified number as a double.

Number (Java SE 19 & JDK 19) 
final Number num1 = Double.valueOf(1.2345);
System.out.println(num1.doubleValue()); // 1.2345

final Number num2 = Double.valueOf(2.9);
System.out.println(num2.doubleValue()); // 2.9

final Number num3 = Double.valueOf(-3.7);
System.out.println(num3.doubleValue()); // -3.7

final Number num1 = Long.valueOf(0L);
System.out.println(num1.doubleValue()); // 0.0

final Number num2 = Long.valueOf(100L);
System.out.println(num2.doubleValue()); // 100.0

final Number num3 = Long.valueOf(Long.MAX_VALUE);
System.out.println(num3.doubleValue()); // 9.223372036854776E18

final Number num4 = Long.valueOf(Long.MIN_VALUE);
System.out.println(num4.doubleValue()); // -9.223372036854776E18

abstract float floatValue ()

Returns the value of the specified number as a float.

Number (Java SE 19 & JDK 19) 
final Number num1 = Float.valueOf(1.2345f);
System.out.println(num1.floatValue()); // 1.2345

final Number num2 = Float.valueOf(2.9f);
System.out.println(num2.floatValue()); // 2.9

final Number num3 = Float.valueOf(-3.7f);
System.out.println(num3.floatValue()); // -3.7

final Number num1 = Long.valueOf(0L);
System.out.println(num1.floatValue()); // 0.0

final Number num2 = Long.valueOf(100L);
System.out.println(num2.floatValue()); // 100.0

final Number num3 = Long.valueOf(Long.MAX_VALUE);
System.out.println(num3.floatValue()); // 9.223372E18

final Number num4 = Long.valueOf(Long.MIN_VALUE);
System.out.println(num4.floatValue()); // -9.223372E18

abstract int intValue ()

Returns the value of the specified number as an int.

Number (Java SE 19 & JDK 19) 
final Number num1 = Integer.valueOf(0);
System.out.println(num1.intValue()); // 0

final Number num2 = Integer.valueOf(100);
System.out.println(num2.intValue()); // 100

final Number num3 = Integer.valueOf(Integer.MAX_VALUE);
System.out.println(num3.intValue()); // 2147483647

final Number num4 = Integer.valueOf(Integer.MIN_VALUE);
System.out.println(num4.intValue()); // -2147483648

final Number num1 = Long.valueOf(2147483647L);
System.out.println(num1.intValue()); // 2147483647

final Number num2 = Long.valueOf(2147483648L);
System.out.println(num2.intValue()); // -2147483648

final Number num3 = Long.valueOf(2147483649L);
System.out.println(num3.intValue()); // -2147483647

final Number num1 = Long.valueOf(-2147483648L);
System.out.println(num1.intValue()); // -2147483648

final Number num2 = Long.valueOf(-2147483649L);
System.out.println(num2.intValue()); // 2147483647

final Number num3 = Long.valueOf(-2147483650L);
System.out.println(num3.intValue()); // 2147483646

final Number num1 = Double.valueOf(1.2345);
System.out.println(num1.intValue()); // 1

final Number num2 = Double.valueOf(2.9);
System.out.println(num2.intValue()); // 2

final Number num3 = Double.valueOf(-3.7);
System.out.println(num3.intValue()); // -3

final Number num1 = Double.valueOf(Double.POSITIVE_INFINITY);
System.out.println(num1.intValue()); // 2147483647

final Number num2 = Double.valueOf(Double.NEGATIVE_INFINITY);
System.out.println(num2.intValue()); // -2147483648

final Number num3 = Double.valueOf(Double.NaN);
System.out.println(num3.intValue()); // 0

abstract long longValue ()

Returns the value of the specified number as a long.

Number (Java SE 19 & JDK 19) 
final Number num1 = Long.valueOf(0L);
System.out.println(num1.longValue()); // 0

final Number num2 = Long.valueOf(100L);
System.out.println(num2.longValue()); // 100

final Number num3 = Long.valueOf(Long.MAX_VALUE);
System.out.println(num3.longValue()); // 9223372036854775807

final Number num4 = Long.valueOf(Long.MIN_VALUE);
System.out.println(num4.longValue()); // -9223372036854775808

final Number num1 = Double.valueOf(1.2345);
System.out.println(num1.longValue()); // 1

final Number num2 = Double.valueOf(2.9);
System.out.println(num2.longValue()); // 2

final Number num3 = Double.valueOf(-3.7);
System.out.println(num3.longValue()); // -3

final Number num1 = Double.valueOf(Double.POSITIVE_INFINITY);
System.out.println(num1.longValue()); // 9223372036854775807

final Number num2 = Double.valueOf(Double.NEGATIVE_INFINITY);
System.out.println(num2.longValue()); // -9223372036854775808

final Number num3 = Double.valueOf(Double.NaN);
System.out.println(num3.longValue()); // 0

short shortValue ()

Returns the value of the specified number as a short.

Number (Java SE 19 & JDK 19) 
final Number num1 = Short.valueOf((short) 0);
System.out.println(num1.shortValue()); // 0

final Number num2 = Short.valueOf((short) 100);
System.out.println(num2.shortValue()); // 100

final Number num3 = Short.valueOf(Short.MAX_VALUE);
System.out.println(num3.shortValue()); // 32767

final Number num4 = Short.valueOf(Short.MIN_VALUE);
System.out.println(num4.shortValue()); // -32768

final Number num1 = Integer.valueOf(32767);
System.out.println(num1.shortValue()); // 32767

final Number num2 = Integer.valueOf(32768);
System.out.println(num2.shortValue()); // -32768

final Number num3 = Integer.valueOf(32769);
System.out.println(num3.shortValue()); // -32767

final Number num1 = Integer.valueOf(-32768);
System.out.println(num1.shortValue()); // -32768

final Number num2 = Integer.valueOf(-32769);
System.out.println(num2.shortValue()); // 32767

final Number num3 = Integer.valueOf(-32770);
System.out.println(num3.shortValue()); // 32766

final Number num1 = Double.valueOf(1.2345);
System.out.println(num1.shortValue()); // 1

final Number num2 = Double.valueOf(2.9);
System.out.println(num2.shortValue()); // 2

final Number num3 = Double.valueOf(-3.7);
System.out.println(num3.shortValue()); // -3

final Number num1 = Double.valueOf(Double.POSITIVE_INFINITY);
System.out.println(num1.shortValue()); // -1

final Number num2 = Double.valueOf(Double.NEGATIVE_INFINITY);
System.out.println(num2.shortValue()); // 0

final Number num3 = Double.valueOf(Double.NaN);
System.out.println(num3.shortValue()); // 0

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