Java Code Conventions: must match pattern '^[a-z][a-zA-Z0-9]*$'

Question

I would like to use the following constant:

final String ADD = "Add text";

However, my CheckStyle tool tells me that 'ADD' does not match the pattern '^[a-z][a-zA-Z0-9]*$'.

Could anyone please tell me what is wrong with 'ADD'? Means '^[a-z][a-zA-Z0-9]*$' that every name has to start with a low character? Is there no other possibility?

Answer 1

^[a-z][a-zA-Z0-9]*$

This regex describes something which starts with lowercase and the remainder is composed of uppercase, lowercase, and numbers. (Examples: aVariable, variable, aNewVariable, variable7, aNewVariable7.)

If you want your field to be constant and static, use:

static final String ADD = "Add text";

Otherwise, use:

final String add = "Add text";

Answer 2

If it is a constant you want, it should also be static

static final String ADD = "Add text";

Constants normally use uppercase letters, but since your variable was not static, it was not interpreted as a constant.

Answer 3

This Regex indicate the need for camelCase with the first letter being small and then every next word having the first letter in it as capital letter.

Answer 4

I just ran into the same problem, turns out it was because it is expected for the Java codebase I was working on to use camel case for all variables as the naming convention. So be sure to check if your variables are named according to the regex pattern ^[a-z]([a-z0-9][a-zA-Z0-9]*)?$. In my case, I got stuck in the Python mode and had my variable named version_regex instead of versionRegex. Once I have made the needed correction the error is no longer thrown.

Answer 5

^[a-z][a-zA-Z0-9]*$

This regex describes something which starts with lowercase and the remainder is composed of uppercase, lowercase, and numbers. (Examples: aVariable, variable, aNewVariable, variable7, aNewVariable7.)

If you want your field to be constant and static, use:

static final String ADD = "Add text";

Otherwise, use:

final String add = "Add text";

Answer 6

If it is a constant you want, it should also be static

static final String ADD = "Add text";

Constants normally use uppercase letters, but since your variable was not static, it was not interpreted as a constant.

Answer 7

This Regex indicate the need for camelCase with the first letter being small and then every next word having the first letter in it as capital letter.

Answer 8

I just ran into the same problem, turns out it was because it is expected for the Java codebase I was working on to use camel case for all variables as the naming convention. So be sure to check if your variables are named according to the regex pattern ^[a-z]([a-z0-9][a-zA-Z0-9]*)?$. In my case, I got stuck in the Python mode and had my variable named version_regex instead of versionRegex. Once I have made the needed correction the error is no longer thrown.