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Literal decimal floating-point numbers cannot always be precisely represented as an IEEE 754 floating-point value. Consequently, the BigDecimal(double val) constructor must not be passed a floating-point literal as an argument when doing so results in an unacceptable loss of precision.

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

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

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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"));

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

Automated Detection

Automated detection is straightforward.

Bibliography

[JLS

2005]

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 Removed      03. Numeric Types and Operations (NUM)