child of #14942
I have read check documentation: https://checkstyle.org/checks/naming/constantname.html
I have downloaded the latest checkstyle from: https://checkstyle.org/cmdline.html#Download_and_Run
I have executed the cli and showed it below, as cli describes the problem better than 1,000 words

From check documentation:

A constant is a static and final field or an interface/annotation field, except serialVersionUID and serialPersistentFields.

unnamed variables can't be field

PS D:\CS\test> cat src/Test.java                                                
import java.util.PriorityQueue;
import java.util.Queue;

public class Test {
  final static int _ = 0;
}
PS D:\CS\test> javac  src/Test.java
src\Test.java:5: error: underscore not allowed here
  final static int _ = 0;
                   ^
1 error
PS D:\CS\test> 

Describe what you expect in detail.

no update is needed this can be closed