NumericalPrefixesInfixesSuffixesCharacterCase
Since Checkstyle 13.2.0
Description
Checks that all numerical literal prefixes, infixes, and suffixes are written using lowercase letters (for example prefixes :
0x, 0b, infixes : e, p, suffixes : f, d). This convention follows the OpenJDK Style Guide. ATTENTION:
This check ignores the L suffix for long literals, as using an uppercase L is a widely accepted and recommended practice to avoid confusion with the digit 1.
Examples
To configure the check:
<module name="Checker">
<module name="TreeWalker">
<module name="NumericalPrefixesInfixesSuffixesCharacterCase"/>
</module>
</module>
Example:
public class Example1 {
int hex1 = 0X1A; // violation 'Numerical prefix should be in lowercase.'
int hex2 = 0x1A;
int bin1 = 0B1010; // violation 'Numerical prefix should be in lowercase.'
int bin2 = 0b1010;
float exp1 = 1.23E3f; // violation 'Numerical infix should be in lowercase.'
float exp2 = 1.23e3f;
double hexEx1 = 0x1.3P2; // violation 'Numerical infix should be in lowercase.'
double hexEx2 = 0x1.3p2;
float suf1 = 10F; // violation 'Numerical suffix should be in lowercase.'
float suf2 = 10f;
double suf3 = 10D; // violation 'Numerical suffix should be in lowercase.'
double suf4 = 10d;
float mix1 = 1.2E3F; // violation 'Numerical infix should be in lowercase.'
float mix3 = 1.2e3f;
double mix4 = 0x1.3P2D; // violation 'Numerical infix should be in lowercase.'
double mix5 = 0x1.3p2D; // violation 'Numerical suffix should be in lowercase.'
double mix6 = 0x1.3p2d;
int ok1 = 0x1F; // ok, here 'F' is a hexadecimal digit, not a numeric suffix.
double ok2 = 123.456;
double ok3 = 1 / 5432.0;
// ok, here 'E' is a hexadecimal digit, not a numeric infix.
double ok4 = 0x1E2.2p2d;
}
Example of Usage
Violation Messages
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Fully Qualified Name
com.puppycrawl.tools.checkstyle.checks.NumericalPrefixesInfixesSuffixesCharacterCaseCheck
Use this fully qualified class name in configuration when an exact class reference is required.






