Fix NPE when opening a non existing file from the recent files menu

dialogService object was null, because the FileHistoryMenu class is initialized before the ctor of JabRef frame creates the dialog service object

CHANGELOG.md

@@ -25,6 +25,8 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed an error where the number of matched entries shown in the group pane was not updated correctly. [#4441](https://github.com/JabRef/jabref/issues/4441)
 - We fixed an error mentioning "javafx.controls/com.sun.javafx.scene.control" that was thrown when interacting with the toolbar.
 - We fixed an error where a cleared search was restored after switching libraries. [#4846](https://github.com/JabRef/jabref/issues/4846) 
+- We fixed an exception which occured when trying to open a non existing file from the "Recent files"-menu [#5334](https://github.com/JabRef/jabref/issues/5334)
+
 
 ### Removed
 

src/main/java/org/jabref/gui/menus/FileHistoryMenu.java

@@ -17,14 +17,12 @@ public class FileHistoryMenu extends Menu {
     private final FileHistory history;
     private final JabRefFrame frame;
     private final JabRefPreferences preferences;
-    private final DialogService dialogService;
 
     public FileHistoryMenu(JabRefPreferences preferences, JabRefFrame frame) {
         setText(Localization.lang("Recent libraries"));
 
         this.frame = frame;
         this.preferences = preferences;
-        this.dialogService = frame.getDialogService();
         history = preferences.getFileHistory();
         if (history.isEmpty()) {
             setDisable(true);
@@ -63,7 +61,7 @@ public void storeHistory() {
 
     public void openFile(Path file) {
         if (!Files.exists(file)) {
-            dialogService.showErrorDialogAndWait(
+            frame.getDialogService().showErrorDialogAndWait(
                     Localization.lang("File not found"),
                     Localization.lang("File not found") + ": " + file);
             history.removeItem(file);