/var/tmp $ javac Test1.java

/var/tmp $ cat config.xml
<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
          "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name = "Checker">
    <module name="TreeWalker">
        <module name="VariableDeclarationUsageDistance">
          <property name="validateBetweenScopes" value="true"/>
          <property name="allowedDistance" value="1"/>
        </module> 
    </module>
</module>

/var/tmp $ cat Test1.java

import java.util.Iterator;

public class Test1 {
    public void method(){
        int a=1;
        class GeneralLogic {
            public <T> Iterator<T> method(T[] b) throws Exception{
                if(a>0){
                    System.out.println(b.length);
                }
                return null;
            }
        }
    }
}


/var/tmp $ RUN_LOCALE="-Duser.language=en -Duser.country=US"
/var/tmp $ java $RUN_LOCALE -jar checkstyle-10.9.3-all.jar -c config.xml Test1.java

Starting audit...
[WARN] /var/tmp/Test.java:5:9: Distance between variable 'a' declaration and its first usage is 3,
 but allowed 1.  Consider making that variable final if you still need to store its value in 
advance (before method calls that might have side effects on the original value).
 [VariableDeclarationUsageDistance]
Audit done.