Java : Number with Examples
Last Modified : December 31, 2023 Published : 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.
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.
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.
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.
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.
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.
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.
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.
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