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Decimal Literal decimal floating-point numbers cannot always be precisely represented as a BigDecimal if the BigDecimal(double val) constructor is used. The primitive type double cannot precisely represent all decimal fractions, because its underlying representation is binaryan IEEE 754 floating-point value. Consequently, the input to the BigDecimal(double val) constructor can lose precision before the constructor is ever invokedmust not be passed a floating-point literal as an argument when doing so results in an unacceptable loss of precision.

Noncompliant Code Example

This noncompliant code example passes a double value to the BigDecimal constructor. Because of thisthe decimal literal 0.1 cannot be precisely represented by a double, precision of the literal BigDecimal is affected.

// printsPrints 0.1000000000000000055511151231257827021181583404541015625
// when run in FP-strict mode 
System.out.println(new BigDecimal(0.1)); 

Compliant Solution

This compliant solution passes the decimal literal as a String so that the BigDecimal(String val) constructor is invoked . and the precision is preserved:

// printsPrints 0.1
// when run in FP-strict mode 
System.out.println(new BigDecimal("0.1"));

Risk Assessment

Using the BigDecimal(double val) constructor with decimal floating-point literals leads can lead to loss of precision.

Automated Detection

Automated detection appears to be is straightforward.

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this guideline on the CERT website.

Bibliography

[JLS 2005]

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Bibliography

[JLS 2015]
[Seacord 2015]	Image Added NUM10-J. Do not construct BigDecimal objects from floating-point literals LiveLesson

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Image Added Image Added Image Added use floating point variables as loop counters      07. Floating Point (FLP)      FLP09-J. Do not rely on the default string representation of floating point values