The Google Java Style Guide §5.2.4 requires constant names to use
CONSTANT_CASE.
When naming a field with CONSTANT_CASE, make sure the field is static,
final, and of immutable type. If the field doesn’t meet those criteria, use
lowerCamelCase instead.
The check recognizes all primitive, String, and enum fields as deeply
immutable. It is possible to create mutable enums, but doing so is
strongly discouraged.
Suppress false positives by adding the suppression annotation @SuppressWarnings("ConstantField") to the enclosing element.