Literal decimal floating-point numbers can not always be represented precisely using the double primitive type, because the underlying representation of double is binary. This imprecision becomes apparent when a BigDecimal is constructed from a double.
Consequently, the BigDecimal(double val) constructor must not be invoked with floating-point literals.
Noncompliant Code Example
This noncompliant code example passes a double value to the BigDecimal constructor. Because the decimal literal 0.1 can not be precisely represented by a double, precision of the BigDecimal is affected.
// prints 0.1000000000000000055511151231257827021181583404541015625 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 precision is preserved.
// prints 0.1
System.out.println(new BigDecimal("0.1"));
Risk Assessment
Using the BigDecimal(double val) constructor with decimal floating point literals can lead to loss of precision.
Guideline |
Severity |
Likelihood |
Remediation Cost |
Priority |
Level |
|---|---|---|---|---|---|
NUM08-J |
low |
probable |
low |
P6 |
L2 |
Automated Detection
Automated detection appears to be straightforward.
Related Vulnerabilities
Search for vulnerabilities resulting from the violation of this guideline on the CERT website.
Bibliography
[JLS 2005]
NUM07-J. Do not use floating point variables as loop counters 03. Floating Point (FLP) NUM09-J. Do not rely on the default string representation of floating point values