System.getProperty("user.home") returns /root when running on Tomcat

Question

I am developing my application in Ubuntu. I have one Java web Spring MVC application. In that I have a controller. The client can upload a file (posting through AngularJS). In the controller, I am getting the file and copying to a specific location.

Here is my controller

@RequestMapping(value = "/fileUpload", method = RequestMethod.POST)
@ResponseBody
public String UploadFile(HttpServletRequest request,HttpServletResponse response) {

    SimpleDateFormat sdf = new SimpleDateFormat("MM_dd_yyyy_HHmmss");
    String date = sdf.format(new Date());

    String fileLoc = null;

    MultipartHttpServletRequest mRequest = (MultipartHttpServletRequest) request;

    Iterator<String> itr = mRequest.getFileNames();
    while (itr.hasNext()) {
        MultipartFile mFile = mRequest.getFile(itr.next());
        String fileName = mFile.getOriginalFilename();

        String homePath=System.getProperty("user.home");
        String separator=File.separator;

        fileLoc = homePath + separator + "myapp" + separator + "file-uploads" +
                  separator + date + "_" + fileName;

        System.out.println(fileLoc);
        try {
            File file = new File(fileLoc);

            // If the directory does not exist, create it
            if (!file.getParentFile().exists()) {
                file.getParentFile().mkdirs();
            }
            FileCopyUtils.copy(mFile.getBytes(), file);

        }
        catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }
    return fileLoc;
}

But when I deploy it in tomcat server and run, the file is getting created in root.

When I print the value of fileLoc, it shows

/root/myapp/file-uploads/01_16_2014_000924_document.jpg

I added a main method in the controller.

public static void main(String[] args) {
    String homePath=System.getProperty("user.home");
    String separator=File.separator;

    System.out.println("Home Path: " + homePath);
    System.out.println("Separator: " + separator);
}

When I run this as Java Application, I am getting proper output

Home Path : /home/shiju
Separator : /

Why it's giving root when running on Tomcat?

Answer 1

If you are executing the application with the root user then it is obvious that /root/ will be returned in the user.home property.