The user reports that data is not displayed. What actions will you take?

1. Check the logs on the server: application logs, web server logs (e.g., Tomcat, Jetty), database logs. Look for errors, exceptions, warnings related to the user request or data processing.
2. Check the database status: availability, load, presence of tables and data. Execute a simple SELECT query to ensure data exists and is accessible.
3. Check network interactions:
   • Backend accessibility from the client side (ping, traceroute).
   • Database accessibility from the backend.
   • Use browser developer tools (Network tab) to analyze HTTP requests: check response status (200, 404, 500), presence of data in the response body.
4. Check the code responsible for data retrieval and display:
   • Ensure that the backend request is correctly formed and sent to the database.
   • Verify how data is processed and serialized on the backend for sending to the client.
   • Review frontend code responsible for parsing received data and displaying it (correctness of field access, handling empty or erroneous responses).
5. Obtain more detailed information from the user:
   • Exact URL of the page or action they are performing.
   • Type of data not displayed.
   • Browser used and its version.
   • Approximate timestamp of the issue.
   • Screenshots of the error or empty page.
6. Reproduce the problem: try to perform the same actions as the user in the same environment (or test environment).
7. Use debugging tools: set breakpoints in server and client code to step through execution and observe variable values.

Example of a database query to check data:

SELECT COUNT(*) FROM your_table_name WHERE relevant_filter_condition;

Example of logging code:

// Inside the request handling method
try {
    List<Data> data = dataService.getDataForUser(userId);
    // Log successful data retrieval
    logger.info("Successfully retrieved {} items for user {}", data.size(), userId);
    return ResponseEntity.ok(data);
} catch (Exception e) {
    // Log error during data retrieval
    logger.error("Error retrieving data for user {}", userId, e);
    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Error retrieving data");
}