Wrong NaN comparison¶
ID: java/comparison-with-nan
Kind: problem
Security severity:
Severity: error
Precision: very-high
Tags:
- correctness
Query suites:
- java-security-and-quality.qls
Click to see the query in the CodeQL repository
The special floating-point number NaN is defined to be different from all other floating-point numbers, including itself, when compared using the equality operators, == and !=.
Recommendation¶
To check whether a variable x is NaN use the method isNaN that is defined on both java.lang.Float and java.lang.Double.
Example¶
The expression x == Double.NaN is always false. This expression should be replaced by Double.isNaN(x), which accurately identifies whether x is equal to Double.NaN.
References¶
Java Language Specification: Numerical Equality Operators == and !=.