Why are Java property files not visible in C:Windows

Question

I have a Java program "PropertyWrite" to write a property file "crazy.properties" into the directory C:Windows

import java.io.*;
import java.util.Properties;

public class PropertyWrite {

    public static void main(String[] args) throws Exception {

        File myprop = new File("C:\WINDOWS\crazy.properties");

        Properties props = new Properties();
        props.setProperty("testprop", "crazy");
        OutputStream os = new FileOutputStream(myprop);
        props.store(os, "comment");
        os.close();

        System.out.println(myprop.exists()); // returns true
    }
}

When i search for that file via Windows File Explorer, it is not visible
Also "Cmd -> dir" does not show the file
Somehow the file seems to be hidden

If i try to read the file with my program "PropertyRead"
it works fine and it prints the value "crazy" as expected

import java.io.*;
import java.util.Properties;

public class PropertyRead {

    public static void main(String[] args) throws Exception {

        File myprop = new File("C:\WINDOWS\crazy.properties");
        System.out.println(myprop.exists()); // returns true

        Properties props = new Properties();
        FileInputStream in = new FileInputStream(myprop);
        props.load(in);
        in.close();

        System.out.println(props.getProperty("testprop")); // prints crazy
    }
}

And now it's going crazy:
If i manually create the same file (crazy.properties with content -> testprop=handmade)
and move it to the folder C:Windows the Explorer is able to show the file.
The file seems visible

Now i restart "PropertyRead" -> it prints NOT "handmade" -> it prints "crazy"

What the hell???

Now i delete the file "C:WINDOWScrazy.properties" via Explorer and restart PropertyRead
the file is still there (but invisible) and it prints "crazy"

How can that be?

thanks in advance

question from:https://stackoverflow.com/questions/65834889/why-are-java-property-files-not-visible-in-c-windows

Answer 1

Normal programs without admin rights are not allowed to write to e.g. the Windows directory.

For compatiblity reasons files written to such location may end up in a "VirtualStore" specific to your user profile in some windows versions.

Check %UserProfile%AppDataLocalVirtualStore if your file is there.

Edit: Some further infos how VirtualStore works can be found here: https://answers.microsoft.com/en-us/windows/forum/windows_7-windows_programs/please-explain-virtualstore-for-non-experts/d8912f80-b275-48d7-9ff3-9e9878954227