Number

AI-generated Key Takeaways

• The Number class is an abstract class that serves as the superclass for all numeric wrapper classes in Java.

• It provides methods to convert the represented number into primitive types like byte, double, float, int, long, and short.

• Implementations of Number define the specific behavior of the conversion to these primitive types, which can include rounding or truncation.

• Key subclasses of Number include Integer, Double, Long, Float, Byte, Short, and atomic implementations like AtomicInteger and AtomicLong.

• The conversion semantics for Number implementations often resemble the narrowing or widening primitive conversions defined in the Java Language Specification.

public abstract class Number extends Object
implements Serializable

Known Direct Subclasses AtomicInteger, AtomicLong, Byte, Double, DoubleAccumulator, DoubleAdder, Float, Integer, Long, LongAccumulator, LongAdder, Short AtomicInteger An int value that may be updated atomically.  AtomicLong A long value that may be updated atomically.  Byte The Byte class wraps a value of primitive type byte in an object.  Double The Double class wraps a value of the primitive type double in an object.  DoubleAccumulator One or more variables that together maintain a running double value updated using a supplied function.  DoubleAdder One or more variables that together maintain an initially zero double sum.  Float The Float class wraps a value of primitive type float in an object.  Integer The Integer class wraps a value of the primitive type int in an object.  Long The Long class wraps a value of the primitive type long in an object.  LongAccumulator One or more variables that together maintain a running long value updated using a supplied function.  LongAdder One or more variables that together maintain an initially zero long sum.  Short The Short class wraps a value of primitive type short in an object.

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. The specific semantics of the conversion from the numeric value of a particular Number implementation to a given primitive type is defined by the Number implementation in question. For platform classes, the conversion is often analogous to a narrowing primitive conversion or a widening primitive conversion as defining in The Java™ Language Specification for converting between primitive types. Therefore, conversions may lose information about the overall magnitude of a numeric value, may lose precision, and may even return a result of a different sign than the input. See the documentation of a given Number implementation for conversion details.

Public Constructor Summary

Number()

Public Method Summary

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.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Public Constructors

public Number ()

Public Methods

public byte byteValue ()

Returns the value of the specified number as a byte, which may involve rounding or truncation.

This implementation returns the result of intValue() cast to a byte.

Returns

• the numeric value represented by this object after conversion to type byte.

public abstract double doubleValue ()

Returns the value of the specified number as a double, which may involve rounding.

Returns

• the numeric value represented by this object after conversion to type double.

public abstract float floatValue ()

Returns the value of the specified number as a float, which may involve rounding.

Returns

• the numeric value represented by this object after conversion to type float.

public abstract int intValue ()

Returns the value of the specified number as an int, which may involve rounding or truncation.

Returns

• the numeric value represented by this object after conversion to type int.

public abstract long longValue ()

Returns the value of the specified number as a long, which may involve rounding or truncation.

Returns

• the numeric value represented by this object after conversion to type long.

public short shortValue ()

Returns the value of the specified number as a short, which may involve rounding or truncation.

This implementation returns the result of intValue() cast to a short.

Returns

• the numeric value represented by this object after conversion to type short.