How to avoid platform based NoSuchFileException when using java.nio.file.Paths?

Whenever I run this code locally, the relative path for the file is working just fine but the Kubernetes pod deployment in pre-prod throws NoSuchFileException.

MOCK_DATA_BASE_PATH = "/data/mocks"
private static String getMockDataString(String fileName) {
        try {
            String filePath = MOCK_DATA_BASE_PATH + fileName;
            return Files.lines(Paths.get(filePath))
                    .collect(Collectors.joining(System.lineSeparator()));
        } catch (IOException e) {
            logger.error("Unable to read file {} with reason {}", fileName, e.getMessage());
        }
        return null;
}

When I checked what my local returns for Path projectRoot = Paths.get("").toAbsolutePath(); it returned a local machine specific absolute path like so:/Users/username/path/to/project/mavenModule while the Kubernetes deployment is plainly showing /. Given such difference in both, I'm wondering how I can read the file in both platforms without exception.

The project directory is as such: Project has 3 mvn module1/module2/module2 directories. The files are in path/to/Project/data/mocks/

Real code examples of alternatives would be highly appreciated

Based on the comments I managed to make this approach work:

private static String getMockDataString(String fileName) throws MyServiceException {
        String filePath = MOCK_DATA_BASE_PATH + fileName;
    try (InputStream inputStream = MockResponseUtils.class
            .getClassLoader().getResourceAsStream(filePath)) {
        if (inputStream != null) {
            return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8));
        }
    } catch (IOException e) {
        throw new MyServiceException("Unable to load mock data for file " + MOCK_FILENAME);
    }
    return null;
}