/var/tmp $ javac Test.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="LocalFinalVariableName"/>
  </module>
</module>

/var/tmp $ cat Test.java
public class Test {
	public void foo() {
		try (var _ = lock()) {
		} catch (Exception exception) {
		}
	}

	public AutoCloseable lock() {
		return null;
	}
}

/var/tmp $ RUN_LOCALE="-Duser.language=en -Duser.country=US"
/var/tmp $ java $RUN_LOCALE -jar checkstyle-X.XX-all.jar -c config.xml Test.java
Starting audit...
[ERROR] /home/boris/Test.java:3:26: Name '_' must match pattern '^[a-z][a-zA-Z0-9]*$'. [LocalFinalVariableName]
Audit done.
Checkstyle ends with 1 errors.