public class DoubleAdder extends Number implements Serializable
double sum.  When updates (method add(double)) are
 contended across threads, the set of variables may grow dynamically
 to reduce contention.  Method sum() (or, equivalently doubleValue()) returns the current total combined across the
 variables maintaining the sum. The order of accumulation within or
 across threads is not guaranteed. Thus, this class may not be
 applicable if numerical stability is required, especially when
 combining values of substantially different orders of magnitude.
 This class is usually preferable to alternatives when multiple threads update a common value that is used for purposes such as summary statistics that are frequently updated but less frequently read.
This class extends Number, but does not define
 methods such as equals, hashCode and compareTo because instances are expected to be mutated, and so are
 not useful as collection keys.
| Constructor and Description | 
|---|
| DoubleAdder()Creates a new adder with initial sum of zero. | 
| Modifier and Type | Method and Description | 
|---|---|
| void | add(double x)Adds the given value. | 
| double | doubleValue()Equivalent to  sum(). | 
| float | floatValue()Returns the  sum()as afloatafter a narrowing primitive conversion. | 
| int | intValue()Returns the  sum()as anintafter a
 narrowing primitive conversion. | 
| long | longValue()Returns the  sum()as alongafter a
 narrowing primitive conversion. | 
| void | reset()Resets variables maintaining the sum to zero. | 
| double | sum()Returns the current sum. | 
| double | sumThenReset() | 
| String | toString()Returns the String representation of the  sum(). | 
byteValue, shortValuepublic void add(double x)
x - the value to addpublic double sum()
public void reset()
public double sumThenReset()
sum() followed by reset(). This method may apply for example during quiescent
 points between multithreaded computations.  If there are
 updates concurrent with this method, the returned value is
 not guaranteed to be the final value occurring before
 the reset.public double doubleValue()
sum().doubleValue in class Numberpublic long longValue()
sum() as a long after a
 narrowing primitive conversion.public int intValue()
sum() as an int after a
 narrowing primitive conversion.public float floatValue()
sum() as a float
 after a narrowing primitive conversion.floatValue in class Numberfloat. Submit a bug or feature 
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
 Copyright © 1993, 2025, Oracle and/or its affiliates.  All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.