private static PathOrException getUserHome(final Properties javaSystemProperties, final Logger logger) {
        return normalizePathInJavaSystemProperty("user.home", javaSystemProperties, logger);
    }
Builds the eventual Embulk system properties from the command line, environment variables, and the actual file system.
embulk-core/src/main/java/org/embulk/cli/EmbulkSystemPropertiesBuilder.java