Why does my application crash when it tries to open a file after the phone restarts?

Eulerrr :

I'm developing an application that recieves a file from the user and inserts the URI into a SQLite db:

    public void getBook(){                     // called when the user wants to give a file to the app
        Intent chooseFile = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        chooseFile.setType("text/plain");
        chooseFile = Intent.createChooser(chooseFile, "Choose a file");
        startActivityForResult(chooseFile, FILE_CHOOSER_REQUEST_CODE);
    }

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == FILE_CHOOSER_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
            Uri u = data.getData();
            addBook(u);   // addBook adds u.toString() to the db
        }
    }

My application uses the following code to read the file (it gets u by using Uri.parse() on the string from the db):

    private void readFile(Uri u, String lang, String name){
        try {
            InputStream is = getContentResolver().openInputStream(u);  //the code crashes on this line
            \\ some code...
        }
        catch(java.io.IOException e){
            Toast.makeText(MainActivity.this, R.string.file_not_found, Toast.LENGTH_SHORT).show();
        }
    }

This works fine even when I reopen the app, but after the phone gets restarted I'm getting the following error:

2020-03-06 11:31:49.687 5664-5664/com.example.android.readme E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.android.readme, PID: 5664
    java.lang.SecurityException: Permission Denial: opening provider com.android.providers.downloads.DownloadStorageProvider from ProcessRecord{93bfa52 5664:com.example.android.readme/u0a163} (pid=5664, uid=10163) requires that you obtain access using ACTION_OPEN_DOCUMENT or related APIs
        at android.os.Parcel.readException(Parcel.java:2013)
        at android.os.Parcel.readException(Parcel.java:1959)
        at android.app.IActivityManager$Stub$Proxy.getContentProvider(IActivityManager.java:4758)
        at android.app.ActivityThread.acquireProvider(ActivityThread.java:5836)
        at android.app.ContextImpl$ApplicationContentResolver.acquireUnstableProvider(ContextImpl.java:2526)
        at android.content.ContentResolver.acquireUnstableProvider(ContentResolver.java:1780)
        at android.content.ContentResolver.openTypedAssetFileDescriptor(ContentResolver.java:1394)
        at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:1247)
        at android.content.ContentResolver.openInputStream(ContentResolver.java:967)
        at com.example.android.readme.MainActivity.readFile(MainActivity.java:162)
        at com.example.android.readme.MainActivity.access$300(MainActivity.java:25)
        at com.example.android.readme.MainActivity$1.onItemClick(MainActivity.java:84)
        at android.widget.AdapterView.performItemClick(AdapterView.java:318)
        at android.widget.AbsListView.performItemClick(AbsListView.java:1158)
        at android.widget.AbsListView$PerformClick.run(AbsListView.java:3127)
        at android.widget.AbsListView$3.run(AbsListView.java:4042)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6494)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

Why does it happen? (I do use ACTION_OPEN_DOCUMENT in my code.)

Thanks in advance for any help!

CommonsWare :

addBook(u);   // addBook adds u.toString() to the db

By default, your rights to access the content identified by the Uri is limited to the activity instance that was given the Uri via onActivityResult(). In particular, your rights go away when your process does.

If you are going to persist the Uri from ACTION_OPEN_DOCUMENT and try to use that Uri again the next day/week/month/year, you need to call takePersistableUriPermission() on ContentResolver first, before saving your Uri to the database.