Servlet can't output HashMap keys to jsp: FileNotFoundException, util class can't find local file after deployment

Question

I have a TranslateServlet that takes some text, creates an instance of a Cracker class and calls a getCrackedResult method which returns a HashMap of keys and values:

public class TranslateServlet extends HttpServlet {
    public static void main(String[] args) {
        Cracker cracker = new Cracker("German", "English");
        HashMap<String, ArrayList<Cracker.EntrySet<String, ArrayList<String>>>> crackedResults =
                cracker.getCrackedResult("Ich bin");

        for (String category: crackedResults.keySet())  {
            System.out.print(category);  //works fine
        }

    }


    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws IOException, ServletException {
        Cracker cracker = new Cracker("German", "English");

        HashMap<String, ArrayList<Cracker.EntrySet<String, ArrayList<String>>>> crackedResults =
                cracker.getCrackedResult("Ich bin");

        for (String category: crackedResults.keySet())  {
                response.getWriter().print(category);  //doesn't work
        }

        response.getWriter().print("DONE");  //works fine
    }
}

However, while iterating over a HashMap inside the main method works fine, when trying to get the key values through doPost() method, I only get DONE as an output, and no other values. Why??

EDIT: "Doesn't work" means doesn't output categories. If the main method outputs "Dog", "Cat", the jsp page only outputs "Done", instead of "Dog", "Cat", "Done".

What is wrong with my question to suffice closing it? Thank you anonymous downvoter too.

EDIT: I checked the tomcat's log and there is a java.io.FileNotFoundException: some_folder/some_file.bin error every time the servlet is called.

I realised that the function getCrackedResult makes use of a local file like this:

InputStream inputPOS = new FileInputStream("some_folder/some_file.bin");

I tried moving the file to WEB-INF and changing the file path:

InputStream inputPOS = new FileInputStream("WEB-INF/some_folder/some_file.bin");

But I still get the exception: java.io.FileNotFoundException: WEB-INF/some_folder/some_file.bin.

How should I deal with the file so that Cracker class, specifically its getCrackedResults function could get it after deployment. My file structure looks like this:

Project Root
------------src
---------------com
------------------util
----------------------Cracker.java
------------------web
---------------------TranslateServlet.java
------------target
------------------classes
-------------------------com
----------------------------util
--------------------------------Cracker.class
----------------------------web
-------------------------------TranslateServlet.class
------------imgs
------------some_folder
-----------------------some_file.bin
------------WEB-INF
-------------------classes
-------------------lib
-------------------some_folder
------------------------------some_file.bin (tried putting it here)

Answer 1

Solution:

Please deploy(!) /WEB-INF/some_file/some.bin at the correct location, then you can access its FileInputStream from a servlet environment like:

java.io.InputStream inS = /*httpRequest.get*/servletContext
    .getResourceAsStream("/WEB-INF/some_file/some.bin");

See: ServletContext Javadoc (Java8)

Answer 2

For now, I managed to fix it with

InputStream inputPOS = Cracker.class.getClassLoader().getResourceAsStream("some_folder/some_file.bin");

solution and placing some_folder/some_file.bin both inside

1. Project Root/target/classes (so that code would work inside IDE)

and

2. Project Root/WEB-INF/classes (so that code would work when deployed on tomcat).