Why you should care
The difference between private and protected visibility is that child classes can see and use protected members, but they cannot see private ones. Since a final class will have no children, marking the members of a final class protected is confusingly pointless.
Note that the protected members of a class can also be seen and used by other classes that are placed within the same package, this could lead to accidental, unintended access to otherwise private members.
How we detect
CAST Highlight counts one occurrence each time a final class has a protected member.
Bad Code
public final class MyFinalClass {
protected String name = "Fred";
protected void setName(String name) {
// ...
}
References
About CAST and Highlight’s Code Insights
Over the last 25 years, CAST has leveraged unique knowledge on software quality measurement by analyzing thousands of applications and billions of lines of code. Based on this experience and community standards on programming best practices, Highlight implements hundreds of code insights across 15+ technologies to calculate health factors of a software.