Class Number

java.lang.Object

java.lang.Number

All Implemented Interfaces:: Serializable

Direct Known Subclasses:: AtomicInteger, AtomicLong, BigDecimal, BigInteger, Byte, Double, DoubleAccumulator, DoubleAdder, Float, Float16, Integer, Long, LongAccumulator, LongAdder, Short

public abstract class Number extends Object implements Serializable

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 defined 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.

See Java Language Specification:

5.1.2 Widening Primitive Conversion
5.1.3 Narrowing Primitive Conversion

Since:

1.0

See Also:

Constructor Summary

Constructor	Description
`Number()`	Constructor for subclasses to call.

Method Summary

Modifier and Type	Method	Description
`byte`	`byteValue()`	Returns the value of the specified number as a `byte`.
`abstract double`	`doubleValue()`	Returns the value of the specified number as a `double`.
`abstract float`	`floatValue()`	Returns the value of the specified number as a `float`.
`abstract int`	`intValue()`	Returns the value of the specified number as an `int`.
`abstract long`	`longValue()`	Returns the value of the specified number as a `long`.
`short`	`shortValue()`	Returns the value of the specified number as a `short`.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()`	Returns a string representation of the object.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

Number

public Number()

Constructor for subclasses to call.

Method Details

intValue

public abstract int intValue()

Returns the value of the specified number as an int.

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

longValue

public abstract long longValue()

Returns the value of the specified number as a long.

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

floatValue

public abstract float floatValue()

Returns the value of the specified number as a float.

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

doubleValue

public abstract double doubleValue()

Returns the value of the specified number as a double.

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

byteValue

public byte byteValue()

Returns the value of the specified number as a byte.

Implementation Requirements:: The default implementation returns the result of intValue() cast to a byte.
Returns:: the numeric value represented by this object after conversion to type byte.
Since:: 1.1

shortValue

public short shortValue()

Returns the value of the specified number as a short.

Implementation Requirements:: The default implementation returns the result of intValue() cast to a short.
Returns:: the numeric value represented by this object after conversion to type short.
Since:: 1.1

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.