private static ClassLoader selectClassLoader() {
        return Optional.ofNullable(Thread.currentThread().getContextClassLoader())
            .orElseGet(FreemarkerSqlLocator.class::getClassLoader);
    }
Locates SQL in {@code .sql.ftl} Freemarker files on the classpath.
freemarker/src/main/java/org/jdbi/v3/freemarker/FreemarkerSqlLocator.java