[EC4] [Java] Rule "Avoid using global variables" discussion

[dedece35]

Is your feature request related to a problem? Please describe.
The java rule Avoid using global variables with id cnumr-java:D4 isn't really "good" for our society for different reasons :

• java IDE generates automatically a global variable with serialID for classes implementing "Serializable" interface : we have a lot this kind of modification : please see capture
• it's a good practice in java language to have a common global variable representing a constant used in one or several classes : please see capture
• it's a good practice in java language to have a common global variable with pre-compiled regex Pattern to avoid compiling this pattern each time a local method is called. This rule is against native SaonrQube rule Regex patterns should not be created needlessly (id : java:S4248) : please see capture

please check also rule Avoid using Pattern.compile() in a non-static context. (id cnumr-java:S77) because it's quite against the rule Avoid using global variables (id cnumr-java:D4)

Describe the solution you'd like

• for the moment, this rule is disabled in our SonarQube
• check why this rule is relevant in our plugin

what is your point of view @glalloue, @jules-delecour-dav, @jhertout, @olegoaer, @mdubois81 ?

[jhertout]

I did not know the rule but I agree with you @dedece35. If this rule is not compliant with eco-development, we have to justify it by:

• demonstrating its energy consumption
• indicating the good practice

With that we can begin to discuss with team developers but else I think I that I should have deactivated the rule in the same situation.

[MP-Aubay]

Hi @dedece35 ,

I totally agree with you concerning constant, I do not know why this rule have been merged without change, I was highlighting it in the PR: cnumr/ecoCode#93

In Java we could consider that this code could be bad practice:

public class HelloWorld {
    public static String myGlobalVariable;
}

But concerning memory consumption I do not know if this rule is pertinent in Java.