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https://issues.apache.org/jira/browse/KAFKA-9642?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Soontaek Lim updated KAFKA-9642:
--------------------------------
Description:
I recommend not to use the BigDecimal(double) constructor. Because of floating
point imprecision, we're unlikely to get the value we expect from that
constructor.
Instead, we should use BigDecimal.valueOf, which uses a string under the covers
to eliminate floating-point rounding errors, or the constructor that takes a
String argument.
>From JavaDocs
The results of this constructor can be somewhat unpredictable. One might assume
that writing new BigDecimal(0.1) in Java creates a BigDecimal which is exactly
equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is actually
equal to 0.1000000000000000055511151231257827021181583404541015625. This is
because 0.1 cannot be represented exactly as a double (or, for that matter, as
a binary fraction of any finite length). Thus, the value that is being passed
in to the constructor is not exactly equal to 0.1, appearances notwithstanding.
was:
I recommend not to use the BigDecimal(double) constructor. Because of floating
point imprecision, we're unlikely to get the value we expect from that
constructor.
Instead, we should use BigDecimal.valueOf, which uses a string under the covers
to eliminate floating-point rounding errors.
>From JavaDocs
The results of this constructor can be somewhat unpredictable. One might assume
that writing new BigDecimal(0.1) in Java creates a BigDecimal which is exactly
equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is actually
equal to 0.1000000000000000055511151231257827021181583404541015625. This is
because 0.1 cannot be represented exactly as a double (or, for that matter, as
a binary fraction of any finite length). Thus, the value that is being passed
in to the constructor is not exactly equal to 0.1, appearances notwithstanding.
> "BigDecimal(double)" should not be used
> ---------------------------------------
>
> Key: KAFKA-9642
> URL: https://issues.apache.org/jira/browse/KAFKA-9642
> Project: Kafka
> Issue Type: Bug
> Reporter: Soontaek Lim
> Assignee: Soontaek Lim
> Priority: Minor
>
> I recommend not to use the BigDecimal(double) constructor. Because of
> floating point imprecision, we're unlikely to get the value we expect from
> that constructor.
> Instead, we should use BigDecimal.valueOf, which uses a string under the
> covers to eliminate floating-point rounding errors, or the constructor that
> takes a String argument.
>
> From JavaDocs
> The results of this constructor can be somewhat unpredictable. One might
> assume that writing new BigDecimal(0.1) in Java creates a BigDecimal which is
> exactly equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is
> actually equal to 0.1000000000000000055511151231257827021181583404541015625.
> This is because 0.1 cannot be represented exactly as a double (or, for that
> matter, as a binary fraction of any finite length). Thus, the value that is
> being passed in to the constructor is not exactly equal to 0.1, appearances
> notwithstanding.
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