diff --git a/.github/workflows/pr-comment.yml b/.github/workflows/pr-comment.yml
index 3b8ef29091e..e3a82fa08ce 100644
--- a/.github/workflows/pr-comment.yml
+++ b/.github/workflows/pr-comment.yml
@@ -43,7 +43,7 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
       - name: jbang
         if: ${{ steps.read-pr_number.outputs.pr_number != '' }}
-        uses: jbangdev/jbang-action@v0.118.0
+        uses: jbangdev/jbang-action@v0.119.0
         with:
           script: ghprcomment@koppor/ghprcomment
           scriptargs: "-r JabRef/jabref -p ${{ steps.read-pr_number.outputs.pr_number }} -w ${{ github.event.workflow_run.id }}"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f98cb2c822c..f20a1ec6a4b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,10 +47,12 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - ⚠️ Renamed command line parameters `embeddBibfileInPdf` to `embedBibFileInPdf`, `writeMetadatatoPdf` to `writeMetadataToPdf`, and `writeXMPtoPdf` to `writeXmpToPdf`. [#11575](https://github.com/JabRef/jabref/pull/11575)
 - The browse button for a Custom theme now opens in the directory of the current used CSS file. [#11597](https://github.com/JabRef/jabref/pull/11597)
 - The browse button for a Custom exporter now opens in the directory of the current used exporter file. [#11717](https://github.com/JabRef/jabref/pull/11717)
+- JabRef now uses TLS 1.2 for all HTTPS connections. [#11852](https://github.com/JabRef/jabref/pull/11852)
 - We improved the display of long messages in the integrity check dialog. [#11619](https://github.com/JabRef/jabref/pull/11619)
 - We improved the undo/redo buttons in the main toolbar and main menu to be disabled when there is nothing to undo/redo. [#8807](https://github.com/JabRef/jabref/issues/8807)
 - We improved the DOI detection in PDF imports. [#11782](https://github.com/JabRef/jabref/pull/11782)
 - We improved the performance when pasting and importing entries in an existing library. [#11843](https://github.com/JabRef/jabref/pull/11843)
+- When fulltext search is selected but indexing is deactivated, a dialog is now shown asking if the user wants to enable indexing now [#9491](https://github.com/JabRef/jabref/issues/9491)
 
 ### Fixed
 
@@ -73,6 +75,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We fixed an issue where search result highlighting was incorrectly highlighting the boolean operators. [#11595](https://github.com/JabRef/jabref/issues/11595)
 - We fixed an issue where search result highlighting was broken at complex searches. [#8067](https://github.com/JabRef/jabref/issues/8067)
 - We fixed an exception when searching for unlinked files. [#11731](https://github.com/JabRef/jabref/issues/11731)
+- We fixed an issue with the link to the full text at the BVB fetcher. [#11852](https://github.com/JabRef/jabref/pull/11852)
 - We fixed an issue where two contradicting notifications were shown when cutting an entry in the main table. [#11724](https://github.com/JabRef/jabref/pull/11724)
 - We fixed an issue where unescaped braces in the arXiv fetcher were not treated. [#11704](https://github.com/JabRef/jabref/issues/11704)
 - We fixed an issue where HTML instead of the fulltext pdf was downloaded when importing arXiv entries. [#4913](https://github.com/JabRef/jabref/issues/4913)
diff --git a/build.gradle b/build.gradle
index 1643de2a6ec..99804fafbec 100644
--- a/build.gradle
+++ b/build.gradle
@@ -262,7 +262,7 @@ dependencies {
     implementation 'org.jsoup:jsoup:1.18.1'
     implementation 'com.konghq:unirest-java-core:4.4.4'
     implementation 'com.konghq:unirest-modules-gson:4.4.4'
-    implementation 'org.apache.httpcomponents.client5:httpclient5:5.3.1'
+    implementation 'org.apache.httpcomponents.client5:httpclient5:5.4'
     // endregion
 
     implementation 'org.slf4j:slf4j-api:2.0.16'
@@ -336,7 +336,7 @@ dependencies {
         exclude group: 'com.squareup.retrofit2', module: 'retrofit'
         exclude group: 'org.jetbrains.kotlin'
     }
-    implementation('dev.langchain4j:langchain4j-mistral-ai:0.34.0') {
+    implementation('dev.langchain4j:langchain4j-mistral-ai:0.35.0') {
         exclude group: 'com.squareup.okhttp3'
         exclude group: 'com.squareup.retrofit2', module: 'retrofit'
         exclude group: 'org.jetbrains.kotlin'
@@ -345,7 +345,7 @@ dependencies {
         exclude group: 'com.squareup.okhttp3'
         exclude group: 'com.squareup.retrofit2', module: 'retrofit'
     }
-    implementation('dev.langchain4j:langchain4j-hugging-face:0.34.0') {
+    implementation('dev.langchain4j:langchain4j-hugging-face:0.35.0') {
         exclude group: 'com.squareup.okhttp3'
         exclude group: 'com.squareup.retrofit2', module: 'retrofit'
         exclude group: 'org.jetbrains.kotlin'
@@ -373,11 +373,11 @@ dependencies {
     implementation 'io.zonky.test:embedded-postgres:2.0.7'
     implementation enforcedPlatform('io.zonky.test.postgres:embedded-postgres-binaries-bom:17.0.0')
 
-    testImplementation 'io.github.classgraph:classgraph:4.8.175'
+    testImplementation 'io.github.classgraph:classgraph:4.8.176'
     testImplementation 'org.junit.jupiter:junit-jupiter:5.11.0'
     testImplementation 'org.junit.platform:junit-platform-launcher:1.10.3'
 
-    testImplementation 'org.mockito:mockito-core:5.13.0'
+    testImplementation 'org.mockito:mockito-core:5.14.1'
     testImplementation 'org.xmlunit:xmlunit-core:2.10.0'
     testImplementation 'org.xmlunit:xmlunit-matchers:2.10.0'
     testRuntimeOnly 'com.tngtech.archunit:archunit-junit5-engine:1.3.0'
diff --git a/rewrite.yml b/rewrite.yml
index 0ddc0934f1a..ecaf9b7b001 100644
--- a/rewrite.yml
+++ b/rewrite.yml
@@ -102,6 +102,8 @@ recipeList:
   - org.openrewrite.java.migrate.io.ReplaceFileInOrOutputStreamFinalizeWithClose
   - org.openrewrite.java.migrate.net.JavaNetAPIs
   - org.openrewrite.java.migrate.net.URLConstructorsToURIRecipes
+  - org.openrewrite.java.migrate.util.OptionalNotEmptyToIsPresent
+  - org.openrewrite.java.migrate.util.OptionalNotPresentToIsEmpty
   - org.openrewrite.java.migrate.util.SequencedCollection
   - org.openrewrite.java.migrate.lang.StringFormatted
 
diff --git a/src/main/java/org/jabref/Launcher.java b/src/main/java/org/jabref/Launcher.java
index da2f9cde7e8..ca52a7141d7 100644
--- a/src/main/java/org/jabref/Launcher.java
+++ b/src/main/java/org/jabref/Launcher.java
@@ -172,26 +172,29 @@ private static void initLogging(String[] args) {
     /**
      * @return true if JabRef should continue starting up, false if it should quit.
      */
-    private static boolean handleMultipleAppInstances(String[] args, RemotePreferences remotePreferences) {
+    private static boolean handleMultipleAppInstances(String[] args, RemotePreferences remotePreferences) throws InterruptedException {
         LOGGER.trace("Checking for remote handling...");
         if (remotePreferences.useRemoteServer()) {
             // Try to contact already running JabRef
             RemoteClient remoteClient = new RemoteClient(remotePreferences.getPort());
             if (remoteClient.ping()) {
                 LOGGER.debug("Pinging other instance succeeded.");
-                // We are not alone, there is already a server out there, send command line
-                // arguments to other instance
-                LOGGER.debug("Passing arguments passed on to running JabRef...");
-                if (remoteClient.sendCommandLineArguments(args)) {
-                    // So we assume it's all taken care of, and quit.
-                    // Output to both to the log and the screen. Therefore, we do not have an additional System.out.println.
-                    LOGGER.info("Arguments passed on to running JabRef instance. Shutting down.");
-                    return false;
+                if (args.length == 0) {
+                    // There is already a server out there, avoid showing log "Passing arguments" while no arguments are provided.
+                    LOGGER.warn("This JabRef instance is already running. Please switch to that instance.");
                 } else {
-                    LOGGER.warn("Could not communicate with other running JabRef instance.");
-                    // We do not launch a new instance in presence of an error
-                    return false;
+                    // We are not alone, there is already a server out there, send command line arguments to other instance
+                    LOGGER.debug("Passing arguments passed on to running JabRef...");
+                    if (remoteClient.sendCommandLineArguments(args)) {
+                        // So we assume it's all taken care of, and quit.
+                        // Output to both to the log and the screen. Therefore, we do not have an additional System.out.println.
+                        LOGGER.info("Arguments passed on to running JabRef instance. Shutting down.");
+                    } else {
+                        LOGGER.warn("Could not communicate with other running JabRef instance.");
+                    }
                 }
+                // We do not launch a new instance in presence if there is another instance running
+                return false;
             } else {
                 LOGGER.debug("Could not ping JabRef instance.");
             }
diff --git a/src/main/java/org/jabref/gui/JabRefGUI.java b/src/main/java/org/jabref/gui/JabRefGUI.java
index dc464b1cfa1..4536bdb566f 100644
--- a/src/main/java/org/jabref/gui/JabRefGUI.java
+++ b/src/main/java/org/jabref/gui/JabRefGUI.java
@@ -393,7 +393,9 @@ public void stopBackgroundTasks() {
 
     public static void shutdownThreadPools() {
         LOGGER.trace("Shutting down taskExecutor");
-        taskExecutor.shutdown();
+        if (taskExecutor != null) {
+            taskExecutor.shutdown();
+        }
         LOGGER.trace("Shutting down fileUpdateMonitor");
         fileUpdateMonitor.shutdown();
         LOGGER.trace("Shutting down directoryMonitor");
diff --git a/src/main/java/org/jabref/gui/entryeditor/DeprecatedFieldsTab.java b/src/main/java/org/jabref/gui/entryeditor/DeprecatedFieldsTab.java
index 8fd8b739a79..4fda9b83cc0 100644
--- a/src/main/java/org/jabref/gui/entryeditor/DeprecatedFieldsTab.java
+++ b/src/main/java/org/jabref/gui/entryeditor/DeprecatedFieldsTab.java
@@ -68,7 +68,7 @@ protected SequencedSet<Field> determineFieldsToShow(BibEntry entry) {
         BibDatabaseMode mode = databaseContext.getMode();
         Optional<BibEntryType> entryType = entryTypesManager.enrich(entry.getType(), mode);
         if (entryType.isPresent()) {
-            return entryType.get().getDeprecatedFields(mode).stream().filter(field -> !entry.getField(field).isEmpty()).collect(Collectors.toCollection(LinkedHashSet::new));
+            return entryType.get().getDeprecatedFields(mode).stream().filter(field -> entry.getField(field).isPresent()).collect(Collectors.toCollection(LinkedHashSet::new));
         } else {
             // Entry type unknown -> treat all fields as required (thus no optional fields)
             return new LinkedHashSet<>();
diff --git a/src/main/java/org/jabref/gui/entryeditor/citationrelationtab/semanticscholar/SemanticScholarFetcher.java b/src/main/java/org/jabref/gui/entryeditor/citationrelationtab/semanticscholar/SemanticScholarFetcher.java
index 82ad2767f6a..557a135741e 100644
--- a/src/main/java/org/jabref/gui/entryeditor/citationrelationtab/semanticscholar/SemanticScholarFetcher.java
+++ b/src/main/java/org/jabref/gui/entryeditor/citationrelationtab/semanticscholar/SemanticScholarFetcher.java
@@ -33,7 +33,7 @@ public String getAPIUrl(String entry_point, BibEntry entry) {
 
     @Override
     public List<BibEntry> searchCitedBy(BibEntry entry) throws FetcherException {
-        if (!entry.getDOI().isPresent()) {
+        if (entry.getDOI().isEmpty()) {
             return List.of();
         }
 
@@ -59,7 +59,7 @@ public List<BibEntry> searchCitedBy(BibEntry entry) throws FetcherException {
 
     @Override
     public List<BibEntry> searchCiting(BibEntry entry) throws FetcherException {
-        if (!entry.getDOI().isPresent()) {
+        if (entry.getDOI().isEmpty()) {
             return List.of();
         }
 
diff --git a/src/main/java/org/jabref/gui/linkedfile/DownloadLinkedFileAction.java b/src/main/java/org/jabref/gui/linkedfile/DownloadLinkedFileAction.java
index c81bf261ca2..47402708ad4 100644
--- a/src/main/java/org/jabref/gui/linkedfile/DownloadLinkedFileAction.java
+++ b/src/main/java/org/jabref/gui/linkedfile/DownloadLinkedFileAction.java
@@ -10,10 +10,7 @@
 import java.util.List;
 import java.util.Optional;
 
-import javax.net.ssl.HostnameVerifier;
-import javax.net.ssl.HttpsURLConnection;
 import javax.net.ssl.SSLHandshakeException;
-import javax.net.ssl.SSLSocketFactory;
 
 import javafx.beans.property.DoubleProperty;
 import javafx.beans.property.ReadOnlyDoubleProperty;
@@ -243,8 +240,6 @@ private boolean checkSSLHandshake(URLDownload urlDownload) {
     }
 
     private BackgroundTask<Path> prepareDownloadTask(Path targetDirectory, URLDownload urlDownload) {
-        SSLSocketFactory defaultSSLSocketFactory = HttpsURLConnection.getDefaultSSLSocketFactory();
-        HostnameVerifier defaultHostnameVerifier = HttpsURLConnection.getDefaultHostnameVerifier();
         return BackgroundTask
                 .wrap(() -> {
                     String suggestedName;
@@ -263,7 +258,6 @@ private BackgroundTask<Path> prepareDownloadTask(Path targetDirectory, URLDownlo
                 .then(destination -> new FileDownloadTask(urlDownload.getSource(), destination))
                 .onFailure(ex -> LOGGER.error("Error in download", ex))
                 .onFinished(() -> {
-                    URLDownload.setSSLVerification(defaultSSLSocketFactory, defaultHostnameVerifier);
                     downloadProgress.unbind();
                     downloadProgress.set(1);
                 });
diff --git a/src/main/java/org/jabref/gui/preferences/websearch/WebSearchTabViewModel.java b/src/main/java/org/jabref/gui/preferences/websearch/WebSearchTabViewModel.java
index 71c61a5cf2d..81cc3a2a11a 100644
--- a/src/main/java/org/jabref/gui/preferences/websearch/WebSearchTabViewModel.java
+++ b/src/main/java/org/jabref/gui/preferences/websearch/WebSearchTabViewModel.java
@@ -5,10 +5,6 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 
-import javax.net.ssl.HostnameVerifier;
-import javax.net.ssl.HttpsURLConnection;
-import javax.net.ssl.SSLSocketFactory;
-
 import javafx.beans.property.BooleanProperty;
 import javafx.beans.property.ListProperty;
 import javafx.beans.property.ObjectProperty;
@@ -217,15 +213,10 @@ public void checkCustomApiKey() {
         if (!apiKey.isEmpty()) {
             URLDownload urlDownload;
             try {
-                SSLSocketFactory defaultSslSocketFactory = HttpsURLConnection.getDefaultSSLSocketFactory();
-                HostnameVerifier defaultHostnameVerifier = HttpsURLConnection.getDefaultHostnameVerifier();
-
                 urlDownload = new URLDownload(testUrlWithoutApiKey + apiKey);
                 // The HEAD request cannot be used because its response is not 200 (maybe 404 or 596...).
                 int statusCode = ((HttpURLConnection) urlDownload.getSource().openConnection()).getResponseCode();
                 keyValid = (statusCode >= 200) && (statusCode < 300);
-
-                URLDownload.setSSLVerification(defaultSslSocketFactory, defaultHostnameVerifier);
             } catch (IOException | UnirestException e) {
                 keyValid = false;
             }
diff --git a/src/main/java/org/jabref/gui/search/GlobalSearchBar.java b/src/main/java/org/jabref/gui/search/GlobalSearchBar.java
index b74121f7a39..5bbe833b8c4 100644
--- a/src/main/java/org/jabref/gui/search/GlobalSearchBar.java
+++ b/src/main/java/org/jabref/gui/search/GlobalSearchBar.java
@@ -44,6 +44,7 @@
 import org.jabref.architecture.AllowedToUseClassGetResource;
 import org.jabref.gui.ClipBoardManager;
 import org.jabref.gui.DialogService;
+import org.jabref.gui.LibraryTab;
 import org.jabref.gui.LibraryTabContainer;
 import org.jabref.gui.StateManager;
 import org.jabref.gui.autocompleter.AppendPersonNamesStrategy;
@@ -57,6 +58,7 @@
 import org.jabref.gui.util.BindingsHelper;
 import org.jabref.gui.util.TooltipTextUtil;
 import org.jabref.gui.util.UiTaskExecutor;
+import org.jabref.logic.FilePreferences;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.preferences.AutoCompleteFirstNameMode;
 import org.jabref.logic.search.SearchPreferences;
@@ -96,6 +98,7 @@ public class GlobalSearchBar extends HBox {
     private final DialogService dialogService;
     private final BooleanProperty globalSearchActive = new SimpleBooleanProperty(false);
     private final BooleanProperty illegalSearch = new SimpleBooleanProperty(false);
+    private final FilePreferences filePreferences;
     private GlobalSearchResultDialog globalSearchResultDialog;
     private final SearchType searchType;
 
@@ -109,6 +112,7 @@ public GlobalSearchBar(LibraryTabContainer tabContainer,
         this.stateManager = stateManager;
         this.preferences = preferences;
         this.searchPreferences = preferences.getSearchPreferences();
+        this.filePreferences = preferences.getFilePreferences();
         this.undoManager = undoManager;
         this.dialogService = dialogService;
         this.tabContainer = tabContainer;
@@ -151,7 +155,10 @@ public GlobalSearchBar(LibraryTabContainer tabContainer,
             if (keyBindingRepository.matches(event, KeyBinding.CLEAR_SEARCH)) {
                 searchField.clear();
                 if (searchType == SearchType.NORMAL_SEARCH) {
-                    tabContainer.getCurrentLibraryTab().getMainTable().requestFocus();
+                    LibraryTab currentLibraryTab = tabContainer.getCurrentLibraryTab();
+                    if (currentLibraryTab != null) {
+                        currentLibraryTab.getMainTable().requestFocus();
+                    }
                 }
                 event.consume();
             }
@@ -231,32 +238,59 @@ public GlobalSearchBar(LibraryTabContainer tabContainer,
     }
 
     private void initSearchModifierButtons() {
-        fulltextButton.setSelected(searchPreferences.isFulltext());
         fulltextButton.setTooltip(new Tooltip(Localization.lang("Fulltext search")));
         initSearchModifierButton(fulltextButton);
+
+        EasyBind.subscribe(filePreferences.fulltextIndexLinkedFilesProperty(), enabled -> {
+            if (!enabled) {
+                fulltextButton.setSelected(false);
+            } else if (searchPreferences.isFulltext()) {
+                fulltextButton.setSelected(true);
+            }
+        });
+
         fulltextButton.selectedProperty().addListener((obs, oldVal, newVal) -> {
-            searchPreferences.setSearchFlag(SearchFlags.FULLTEXT, newVal);
+            if (!filePreferences.shouldFulltextIndexLinkedFiles() && newVal) {
+                boolean enableFulltextSearch = dialogService.showConfirmationDialogAndWait(Localization.lang("Fulltext search"), Localization.lang("Fulltext search requires the setting 'Automatically index all linked files for fulltext search' to be enabled. Do you want to enable indexing now?"), Localization.lang("Enable indexing"), Localization.lang("Keep disabled"));
+
+                LibraryTab libraryTab = tabContainer.getCurrentLibraryTab();
+                if (libraryTab != null && enableFulltextSearch) {
+                    filePreferences.setFulltextIndexLinkedFiles(true);
+                    searchPreferences.setSearchFlag(SearchFlags.FULLTEXT, true);
+                }
+                if (!enableFulltextSearch) {
+                    fulltextButton.setSelected(false);
+                    searchPreferences.setSearchFlag(SearchFlags.FULLTEXT, false);
+                }
+            } else {
+                searchPreferences.setSearchFlag(SearchFlags.FULLTEXT, newVal);
+            }
+            searchField.requestFocus();
             updateSearchQuery();
         });
 
         keepSearchString.setSelected(searchPreferences.shouldKeepSearchString());
         keepSearchString.setTooltip(new Tooltip(Localization.lang("Keep search string across libraries")));
         initSearchModifierButton(keepSearchString);
-        keepSearchString.selectedProperty().addListener((obs, oldVal, newVal) -> searchPreferences.setKeepSearchString(newVal));
+        keepSearchString.selectedProperty().addListener((obs, oldVal, newVal) -> {
+            searchPreferences.setKeepSearchString(newVal);
+            searchField.requestFocus();
+        });
 
         filterModeButton.setSelected(searchPreferences.getSearchDisplayMode() == SearchDisplayMode.FILTER);
         filterModeButton.setTooltip(new Tooltip(Localization.lang("Filter search results")));
         initSearchModifierButton(filterModeButton);
-        filterModeButton.setOnAction(event -> searchPreferences.setSearchDisplayMode(filterModeButton.isSelected() ? SearchDisplayMode.FILTER : SearchDisplayMode.FLOAT));
+        filterModeButton.setOnAction(event -> {
+            searchPreferences.setSearchDisplayMode(filterModeButton.isSelected() ? SearchDisplayMode.FILTER : SearchDisplayMode.FLOAT);
+            searchField.requestFocus();
+        });
 
         openGlobalSearchButton.disableProperty().bindBidirectional(globalSearchActive);
         openGlobalSearchButton.setTooltip(new Tooltip(Localization.lang("Search across libraries in a new window")));
         initSearchModifierButton(openGlobalSearchButton);
         openGlobalSearchButton.setOnAction(evt -> openGlobalSearchDialog());
 
-        searchPreferences.getObservableSearchFlags().addListener((SetChangeListener.Change<? extends SearchFlags> change) -> {
-            fulltextButton.setSelected(searchPreferences.isFulltext());
-        });
+        searchPreferences.getObservableSearchFlags().addListener((SetChangeListener.Change<? extends SearchFlags> change) -> fulltextButton.setSelected(searchPreferences.isFulltext()));
     }
 
     public void openGlobalSearchDialog() {
@@ -268,7 +302,7 @@ public void openGlobalSearchDialog() {
             globalSearchResultDialog = new GlobalSearchResultDialog(undoManager, tabContainer);
         }
         stateManager.activeSearchQuery(SearchType.NORMAL_SEARCH).get().ifPresent(query ->
-                    stateManager.activeSearchQuery(SearchType.GLOBAL_SEARCH).set(Optional.of(query)));
+                stateManager.activeSearchQuery(SearchType.GLOBAL_SEARCH).set(Optional.of(query)));
         updateSearchQuery();
         dialogService.showCustomDialogAndWait(globalSearchResultDialog);
         globalSearchActive.setValue(false);
diff --git a/src/main/java/org/jabref/logic/auxparser/DefaultAuxParser.java b/src/main/java/org/jabref/logic/auxparser/DefaultAuxParser.java
index 68c80974aa4..04eab9ccaf8 100644
--- a/src/main/java/org/jabref/logic/auxparser/DefaultAuxParser.java
+++ b/src/main/java/org/jabref/logic/auxparser/DefaultAuxParser.java
@@ -126,7 +126,7 @@ private void resolveTags(AuxParserResult result) {
         List<BibEntry> entriesToInsert = new ArrayList<>();
 
         for (String key : result.getUniqueKeys()) {
-            if (!result.getGeneratedBibDatabase().getEntryByCitationKey(key).isPresent()) {
+            if (result.getGeneratedBibDatabase().getEntryByCitationKey(key).isEmpty()) {
                 Optional<BibEntry> entry = masterDatabase.getEntryByCitationKey(key);
                 if (entry.isPresent()) {
                     entriesToInsert.add(entry.get());
@@ -155,7 +155,7 @@ private void resolveCrossReferences(List<BibEntry> entries, AuxParserResult resu
         List<BibEntry> entriesToInsert = new ArrayList<>();
         for (BibEntry entry : entries) {
             entry.getField(StandardField.CROSSREF).ifPresent(crossref -> {
-                if (!result.getGeneratedBibDatabase().getEntryByCitationKey(crossref).isPresent()) {
+                if (result.getGeneratedBibDatabase().getEntryByCitationKey(crossref).isEmpty()) {
                     Optional<BibEntry> refEntry = masterDatabase.getEntryByCitationKey(crossref);
 
                     if (refEntry.isPresent()) {
diff --git a/src/main/java/org/jabref/logic/bibtex/comparator/BibDatabaseDiff.java b/src/main/java/org/jabref/logic/bibtex/comparator/BibDatabaseDiff.java
index 9e7b5939372..c4161345061 100644
--- a/src/main/java/org/jabref/logic/bibtex/comparator/BibDatabaseDiff.java
+++ b/src/main/java/org/jabref/logic/bibtex/comparator/BibDatabaseDiff.java
@@ -41,7 +41,7 @@ private BibDatabaseDiff(BibDatabaseContext originalDatabase, BibDatabaseContext
     }
 
     private boolean isEmpty() {
-        return !metaDataDiff.isPresent() && !preambleDiff.isPresent() && bibStringDiffs.isEmpty() && entryDiffs.isEmpty();
+        return metaDataDiff.isEmpty() && preambleDiff.isEmpty() && bibStringDiffs.isEmpty() && entryDiffs.isEmpty();
     }
 
     private List<BibEntryDiff> getBibEntryDiffs(BibDatabaseContext originalDatabase, BibDatabaseContext newDatabase) {
diff --git a/src/main/java/org/jabref/logic/cleanup/ConvertToBiblatexCleanup.java b/src/main/java/org/jabref/logic/cleanup/ConvertToBiblatexCleanup.java
index 470d01f335b..19a54049cc3 100644
--- a/src/main/java/org/jabref/logic/cleanup/ConvertToBiblatexCleanup.java
+++ b/src/main/java/org/jabref/logic/cleanup/ConvertToBiblatexCleanup.java
@@ -25,7 +25,7 @@ public List<FieldChange> cleanup(BibEntry entry) {
             Field oldField = alias.getKey();
             Field newField = alias.getValue();
             entry.getField(oldField).ifPresent(oldValue -> {
-                if (!oldValue.isEmpty() && (!entry.getField(newField).isPresent())) {
+                if (!oldValue.isEmpty() && (entry.getField(newField).isEmpty())) {
                     // There is content in the old field and no value in the new, so just copy
                     entry.setField(newField, oldValue).ifPresent(changes::add);
                     entry.clearField(oldField).ifPresent(changes::add);
diff --git a/src/main/java/org/jabref/logic/cleanup/ConvertToBibtexCleanup.java b/src/main/java/org/jabref/logic/cleanup/ConvertToBibtexCleanup.java
index 1b289c091d9..a4e6a5e64d1 100644
--- a/src/main/java/org/jabref/logic/cleanup/ConvertToBibtexCleanup.java
+++ b/src/main/java/org/jabref/logic/cleanup/ConvertToBibtexCleanup.java
@@ -40,7 +40,7 @@ public List<FieldChange> cleanup(BibEntry entry) {
             Field oldField = alias.getValue();
             Field newField = alias.getKey();
             entry.getField(oldField).ifPresent(oldValue -> {
-                if (!oldValue.isEmpty() && (!entry.getField(newField).isPresent())) {
+                if (!oldValue.isEmpty() && (entry.getField(newField).isEmpty())) {
                     // There is content in the old field and no value in the new, so just copy
                     entry.setField(newField, oldValue).ifPresent(changes::add);
                     entry.clearField(oldField).ifPresent(changes::add);
diff --git a/src/main/java/org/jabref/logic/cleanup/FileLinksCleanup.java b/src/main/java/org/jabref/logic/cleanup/FileLinksCleanup.java
index fb72153186f..5e89cacbbec 100644
--- a/src/main/java/org/jabref/logic/cleanup/FileLinksCleanup.java
+++ b/src/main/java/org/jabref/logic/cleanup/FileLinksCleanup.java
@@ -18,7 +18,7 @@ public class FileLinksCleanup implements CleanupJob {
     @Override
     public List<FieldChange> cleanup(BibEntry entry) {
         Optional<String> oldValue = entry.getField(StandardField.FILE);
-        if (!oldValue.isPresent()) {
+        if (oldValue.isEmpty()) {
             return Collections.emptyList();
         }
 
diff --git a/src/main/java/org/jabref/logic/cleanup/ISSNCleanup.java b/src/main/java/org/jabref/logic/cleanup/ISSNCleanup.java
index 735e408b3a5..e703c296c75 100644
--- a/src/main/java/org/jabref/logic/cleanup/ISSNCleanup.java
+++ b/src/main/java/org/jabref/logic/cleanup/ISSNCleanup.java
@@ -14,7 +14,7 @@ public class ISSNCleanup implements CleanupJob {
     @Override
     public List<FieldChange> cleanup(BibEntry entry) {
         Optional<String> issnString = entry.getField(StandardField.ISSN);
-        if (!issnString.isPresent()) {
+        if (issnString.isEmpty()) {
             return Collections.emptyList();
         }
 
diff --git a/src/main/java/org/jabref/logic/importer/FetcherException.java b/src/main/java/org/jabref/logic/importer/FetcherException.java
index 47f672a8c51..cd82a392fb9 100644
--- a/src/main/java/org/jabref/logic/importer/FetcherException.java
+++ b/src/main/java/org/jabref/logic/importer/FetcherException.java
@@ -14,10 +14,8 @@
 
 public class FetcherException extends JabRefException {
     private static final Logger LOGGER = LoggerFactory.getLogger(FetcherException.class);
-
-    Pattern API_KEY_PATTERN = Pattern.compile("(?i)(api|key|api[-_]?key)=[^&]*");
-
-    String REDACTED_STRING = "[REDACTED]";
+    private static final Pattern API_KEY_PATTERN = Pattern.compile("(?i)(api|key|api[-_]?key)=[^&]*");
+    private static String REDACTED_STRING = "[REDACTED]";
 
     private final String url;
     private final SimpleHttpResponse httpResponse;
@@ -91,6 +89,10 @@ private String getRedactedUrl() {
         return API_KEY_PATTERN.matcher(url).replaceAll(REDACTED_STRING);
     }
 
+    public static Object getRedactedUrl(URL source) {
+        return API_KEY_PATTERN.matcher(source.toString()).replaceAll(REDACTED_STRING);
+    }
+
     private String getPrefix() {
         String superLocalizedMessage = super.getLocalizedMessage();
         if (!StringUtil.isBlank(superLocalizedMessage)) {
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/ACS.java b/src/main/java/org/jabref/logic/importer/fetcher/ACS.java
index 73fc7f3ead9..11cf1fd9ca3 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/ACS.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/ACS.java
@@ -26,23 +26,15 @@ public class ACS implements FulltextFetcher {
     private static final String SOURCE = "https://pubs.acs.org/doi/abs/%s";
 
     /**
-     * Tries to find a fulltext URL for a given BibTex entry.
-     * <p>
-     * Currently only uses the DOI if found.
-     *
-     * @param entry The Bibtex entry
-     * @return The fulltext PDF URL Optional, if found, or an empty Optional if not found.
-     * @throws NullPointerException if no BibTex entry is given
-     * @throws java.io.IOException
+     * Tries to find a fulltext URL for a given BibTeX entry.
+     * Requires the entry to have a DOI field.
+     * In case no DOI is present, an empty Optional is returned.
      */
     @Override
     public Optional<URL> findFullText(BibEntry entry) throws IOException {
         Objects.requireNonNull(entry);
-
-        // DOI search
         Optional<DOI> doi = entry.getField(StandardField.DOI).flatMap(DOI::parse);
-
-        if (!doi.isPresent()) {
+        if (doi.isEmpty()) {
             return Optional.empty();
         }
 
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/ApsFetcher.java b/src/main/java/org/jabref/logic/importer/fetcher/ApsFetcher.java
index 2a5ca987964..88de237ab9b 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/ApsFetcher.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/ApsFetcher.java
@@ -35,7 +35,7 @@ public Optional<URL> findFullText(BibEntry entry) throws IOException {
 
         Optional<DOI> doi = entry.getField(StandardField.DOI).flatMap(DOI::parse);
 
-        if (!doi.isPresent()) {
+        if (doi.isEmpty()) {
             return Optional.empty();
         }
 
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/BvbFetcher.java b/src/main/java/org/jabref/logic/importer/fetcher/BvbFetcher.java
index 4cfba366384..e570a13f754 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/BvbFetcher.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/BvbFetcher.java
@@ -14,6 +14,9 @@
 import org.apache.hc.core5.net.URIBuilder;
 import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
 
+/**
+ * Fetcher for <a href="Bibliotheksverbund Bayern (BVB)">https://www.bib-bvb.de/</a>.
+ */
 public class BvbFetcher implements SearchBasedParserFetcher {
 
     private static final String URL_PATTERN = "http://bvbr.bib-bvb.de:5661/bvb01sru?";
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/IEEE.java b/src/main/java/org/jabref/logic/importer/fetcher/IEEE.java
index f74803c8b99..6d1f93e9b65 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/IEEE.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/IEEE.java
@@ -30,6 +30,7 @@
 import org.jabref.model.entry.field.StandardField;
 import org.jabref.model.entry.identifier.DOI;
 import org.jabref.model.entry.types.StandardEntryType;
+import org.jabref.model.strings.StringUtil;
 
 import kong.unirest.core.json.JSONArray;
 import kong.unirest.core.json.JSONObject;
@@ -118,10 +119,9 @@ private static BibEntry parseJsonResponse(JSONObject jsonEntry, Character keywor
         entry.setField(StandardField.ISBN, jsonEntry.optString("isbn"));
         entry.setField(StandardField.ISSN, jsonEntry.optString("issn"));
         entry.setField(StandardField.ISSUE, jsonEntry.optString("issue"));
-        try {
-            entry.addFile(new LinkedFile(URI.create(jsonEntry.optString("pdf_url")).toURL(), "PDF"));
-        } catch (MalformedURLException e) {
-            LOGGER.error("Fetched PDF URL String is malformed.");
+        String pdfUrl = jsonEntry.optString("pdf_url");
+        if (!StringUtil.isBlank(pdfUrl)) {
+            entry.addFile(new LinkedFile("", pdfUrl, "PDF"));
         }
         entry.setField(StandardField.JOURNALTITLE, jsonEntry.optString("publication_title"));
         entry.setField(StandardField.DATE, jsonEntry.optString("publication_date"));
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/MrDLibFetcher.java b/src/main/java/org/jabref/logic/importer/fetcher/MrDLibFetcher.java
index 818f80ea105..570e9777a3f 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/MrDLibFetcher.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/MrDLibFetcher.java
@@ -54,7 +54,7 @@ public String getName() {
     @Override
     public List<BibEntry> performSearch(BibEntry entry) throws FetcherException {
         Optional<String> title = entry.getFieldLatexFree(StandardField.TITLE);
-        if (!title.isPresent()) {
+        if (title.isEmpty()) {
             // without a title there is no reason to ask MrDLib
             return List.of();
         }
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/OpenAccessDoi.java b/src/main/java/org/jabref/logic/importer/fetcher/OpenAccessDoi.java
index 42a89a32f4e..9e12625e4fd 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/OpenAccessDoi.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/OpenAccessDoi.java
@@ -36,7 +36,7 @@ public Optional<URL> findFullText(BibEntry entry) throws IOException {
         Optional<DOI> doi = entry.getField(StandardField.DOI)
                                  .flatMap(DOI::parse);
 
-        if (!doi.isPresent()) {
+        if (doi.isEmpty()) {
             return Optional.empty();
         }
 
diff --git a/src/main/java/org/jabref/logic/importer/fetcher/ResearchGate.java b/src/main/java/org/jabref/logic/importer/fetcher/ResearchGate.java
index abbababcf23..6e4f3269fdd 100644
--- a/src/main/java/org/jabref/logic/importer/fetcher/ResearchGate.java
+++ b/src/main/java/org/jabref/logic/importer/fetcher/ResearchGate.java
@@ -69,7 +69,7 @@ public Optional<URL> findFullText(BibEntry entry) throws IOException, FetcherExc
         try {
             html = getHTML(entry);
         } catch (FetcherException | NullPointerException e) {
-            LOGGER.debug("ResearchGate server is not available");
+            LOGGER.debug("ResearchGate server is not available", e);
             return Optional.empty();
         }
         Elements eLink = html.getElementsByTag("section");
diff --git a/src/main/java/org/jabref/logic/importer/fileformat/MarcXmlParser.java b/src/main/java/org/jabref/logic/importer/fileformat/MarcXmlParser.java
index 195199bc469..1e918099990 100644
--- a/src/main/java/org/jabref/logic/importer/fileformat/MarcXmlParser.java
+++ b/src/main/java/org/jabref/logic/importer/fileformat/MarcXmlParser.java
@@ -18,10 +18,12 @@
 import org.jabref.logic.importer.AuthorListParser;
 import org.jabref.logic.importer.ParseException;
 import org.jabref.logic.importer.Parser;
+import org.jabref.logic.util.StandardFileType;
 import org.jabref.model.entry.AuthorList;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.Date;
 import org.jabref.model.entry.LinkedFile;
+import org.jabref.model.entry.field.Field;
 import org.jabref.model.entry.field.StandardField;
 import org.jabref.model.entry.types.StandardEntryType;
 import org.jabref.model.strings.StringUtil;
@@ -380,17 +382,7 @@ private void putDoi(BibEntry bibEntry, Element datafield) {
 
         if ("e".equals(ind1) && StringUtil.isNotBlank("u") && StringUtil.isNotBlank(resource)) { // DOI
             String fulltext = getSubfield("3", datafield);
-
-            if ("Volltext".equals(fulltext)) {
-                try {
-                    LinkedFile linkedFile = new LinkedFile(URI.create(resource).toURL(), "PDF");
-                    bibEntry.setField(StandardField.FILE, linkedFile.toString());
-                } catch (MalformedURLException e) {
-                    LOGGER.info("Malformed URL: {}", resource);
-                }
-            } else {
-                bibEntry.setField(StandardField.DOI, resource);
-            }
+            handleVolltext(bibEntry, fulltext, resource, StandardField.DOI);
         }
     }
 
@@ -402,17 +394,20 @@ private void putElectronicLocation(BibEntry bibEntry, Element datafield) {
         if ("4".equals(ind1) && "0".equals(ind2)) {
             String fulltext = getSubfield("3", datafield);
             String resource = getSubfield("u", datafield);
+            handleVolltext(bibEntry, fulltext, resource, StandardField.URL);
+        }
+    }
 
-            if ("Volltext".equals(fulltext) && StringUtil.isNotBlank(resource)) {
-                try {
-                    LinkedFile linkedFile = new LinkedFile(URI.create(resource).toURL(), "PDF");
-                    bibEntry.setField(StandardField.FILE, linkedFile.toString());
-                } catch (MalformedURLException e) {
-                    LOGGER.info("Malformed URL: {}", resource);
-                }
-            } else {
-                bibEntry.setField(StandardField.URL, resource);
+    private static void handleVolltext(BibEntry bibEntry, String fieldName, String resource, Field fallBackField) {
+        if ("Volltext".equals(fieldName) && StringUtil.isNotBlank(resource)) {
+            try {
+                LinkedFile linkedFile = new LinkedFile("", URI.create(resource).toURL(), StandardFileType.PDF.getName());
+                bibEntry.setFiles(List.of(linkedFile));
+            } catch (MalformedURLException | IllegalArgumentException e) {
+                LOGGER.info("Malformed URL: {}", resource);
             }
+        } else {
+            bibEntry.setField(fallBackField, resource);
         }
     }
 
diff --git a/src/main/java/org/jabref/logic/integrity/DateChecker.java b/src/main/java/org/jabref/logic/integrity/DateChecker.java
index 83f0077b8aa..a79e37994e8 100644
--- a/src/main/java/org/jabref/logic/integrity/DateChecker.java
+++ b/src/main/java/org/jabref/logic/integrity/DateChecker.java
@@ -15,7 +15,7 @@ public Optional<String> checkValue(String value) {
         }
 
         Optional<Date> parsedDate = Date.parse(value);
-        if (!parsedDate.isPresent()) {
+        if (parsedDate.isEmpty()) {
             return Optional.of(Localization.lang("incorrect format"));
         }
 
diff --git a/src/main/java/org/jabref/logic/integrity/FileChecker.java b/src/main/java/org/jabref/logic/integrity/FileChecker.java
index dc59850c229..d59e3c5d1ea 100644
--- a/src/main/java/org/jabref/logic/integrity/FileChecker.java
+++ b/src/main/java/org/jabref/logic/integrity/FileChecker.java
@@ -36,7 +36,7 @@ public Optional<String> checkValue(String value) {
 
         for (LinkedFile file : linkedFiles) {
             Optional<Path> linkedFile = file.findIn(context, filePreferences);
-            if ((!linkedFile.isPresent()) || !Files.exists(linkedFile.get())) {
+            if ((linkedFile.isEmpty()) || !Files.exists(linkedFile.get())) {
                 return Optional.of(Localization.lang("link should refer to a correct file path"));
             }
         }
diff --git a/src/main/java/org/jabref/logic/msbib/MSBibConverter.java b/src/main/java/org/jabref/logic/msbib/MSBibConverter.java
index 1870254e933..41f030e9be9 100644
--- a/src/main/java/org/jabref/logic/msbib/MSBibConverter.java
+++ b/src/main/java/org/jabref/logic/msbib/MSBibConverter.java
@@ -67,7 +67,7 @@ public static MSBibEntry convert(BibEntry entry) {
         result.day = entry.getFieldOrAliasLatexFree(StandardField.DAY).orElse(null);
         result.month = entry.getMonth().map(Month::getFullName).orElse(null);
 
-        if (!entry.getFieldLatexFree(StandardField.YEAR).isPresent()) {
+        if (entry.getFieldLatexFree(StandardField.YEAR).isEmpty()) {
             result.year = entry.getFieldOrAliasLatexFree(StandardField.YEAR).orElse(null);
         }
         result.journalName = entry.getFieldOrAliasLatexFree(StandardField.JOURNAL).orElse(null);
diff --git a/src/main/java/org/jabref/logic/net/URLDownload.java b/src/main/java/org/jabref/logic/net/URLDownload.java
index b748535a183..6fb9db4cabe 100644
--- a/src/main/java/org/jabref/logic/net/URLDownload.java
+++ b/src/main/java/org/jabref/logic/net/URLDownload.java
@@ -24,6 +24,9 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
+import java.security.KeyManagementException;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
 import java.time.Duration;
 import java.util.Collections;
 import java.util.HashMap;
@@ -32,9 +35,8 @@
 import java.util.Map.Entry;
 import java.util.Optional;
 
-import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.HttpsURLConnection;
-import javax.net.ssl.SSLSocketFactory;
+import javax.net.ssl.SSLContext;
 
 import org.jabref.http.dto.SimpleHttpResponse;
 import org.jabref.logic.importer.FetcherClientException;
@@ -65,7 +67,7 @@
  */
 public class URLDownload {
 
-    public static final String USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36";
+    public static final String USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:130.0) Gecko/20100101 Firefox/130.0";
     private static final Logger LOGGER = LoggerFactory.getLogger(URLDownload.class);
     private static final Duration DEFAULT_CONNECT_TIMEOUT = Duration.ofSeconds(30);
     private static final int MAX_RETRIES = 3;
@@ -74,6 +76,7 @@ public class URLDownload {
     private final Map<String, String> parameters = new HashMap<>();
     private String postData = "";
     private Duration connectTimeout = DEFAULT_CONNECT_TIMEOUT;
+    private SSLContext sslContext;
 
     static {
         Unirest.config()
@@ -96,18 +99,14 @@ public URLDownload(String source) throws MalformedURLException {
     public URLDownload(URL source) {
         this.source = source;
         this.addHeader("User-Agent", URLDownload.USER_AGENT);
-    }
 
-    /**
-     * @param socketFactory trust manager
-     * @param verifier      host verifier
-     */
-    public static void setSSLVerification(SSLSocketFactory socketFactory, HostnameVerifier verifier) {
         try {
-            HttpsURLConnection.setDefaultSSLSocketFactory(socketFactory);
-            HttpsURLConnection.setDefaultHostnameVerifier(verifier);
-        } catch (Exception e) {
-            LOGGER.error("A problem occurred when reset SSL verification", e);
+            sslContext = SSLContext.getInstance("TLSv1.2");
+            sslContext.init(null, null, new SecureRandom());
+            // Note: SSL certificates are installed at {@link TrustStoreManager#configureTrustStore(Path)}
+        } catch (NoSuchAlgorithmException | KeyManagementException e) {
+            LOGGER.error("Could not initialize SSL context", e);
+            sslContext = null;
         }
     }
 
@@ -384,7 +383,7 @@ public URLConnection openConnection() throws FetcherException {
             } else if (status >= 400) {
                 // in case of an error, propagate the error message
                 SimpleHttpResponse httpResponse = new SimpleHttpResponse(httpURLConnection);
-                LOGGER.info("{}", httpResponse);
+                LOGGER.info("{}: {}", FetcherException.getRedactedUrl(this.source), httpResponse);
                 if (status < 500) {
                     throw new FetcherClientException(this.source, httpResponse);
                 } else {
@@ -397,6 +396,15 @@ public URLConnection openConnection() throws FetcherException {
 
     private URLConnection getUrlConnection() throws IOException {
         URLConnection connection = this.source.openConnection();
+
+        if (connection instanceof HttpURLConnection httpConnection) {
+            httpConnection.setInstanceFollowRedirects(true);
+        }
+
+        if ((sslContext != null) && (connection instanceof HttpsURLConnection httpsConnection)) {
+            httpsConnection.setSSLSocketFactory(sslContext.getSocketFactory());
+        }
+
         connection.setConnectTimeout((int) connectTimeout.toMillis());
         for (Entry<String, String> entry : this.parameters.entrySet()) {
             connection.setRequestProperty(entry.getKey(), entry.getValue());
diff --git a/src/main/java/org/jabref/logic/net/ssl/TrustStoreManager.java b/src/main/java/org/jabref/logic/net/ssl/TrustStoreManager.java
index 4e47623846e..3eaf6659167 100644
--- a/src/main/java/org/jabref/logic/net/ssl/TrustStoreManager.java
+++ b/src/main/java/org/jabref/logic/net/ssl/TrustStoreManager.java
@@ -27,6 +27,9 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/**
+ * @implNote SSL certificates are installed at {@link TrustStoreManager#configureTrustStore(Path)}
+ */
 public class TrustStoreManager {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(TrustStoreManager.class);
@@ -163,7 +166,9 @@ public static void createTruststoreFileIfNotExist(Path storePath) {
         }
     }
 
-    // based on https://stackoverflow.com/a/62586564/3450689
+    /**
+     * @implNote based on https://stackoverflow.com/a/62586564/3450689
+     */
     private static void configureTrustStore(Path myStorePath) throws NoSuchAlgorithmException, KeyManagementException, KeyStoreException,
         CertificateException, IOException {
         X509TrustManager jreTrustManager = getJreTrustManager();
diff --git a/src/main/java/org/jabref/migrations/ConvertLegacyExplicitGroups.java b/src/main/java/org/jabref/migrations/ConvertLegacyExplicitGroups.java
index 1b174abd162..63f1ab809c4 100644
--- a/src/main/java/org/jabref/migrations/ConvertLegacyExplicitGroups.java
+++ b/src/main/java/org/jabref/migrations/ConvertLegacyExplicitGroups.java
@@ -18,7 +18,7 @@ public class ConvertLegacyExplicitGroups implements PostOpenMigration {
     @Override
     public void performMigration(ParserResult parserResult) {
         Objects.requireNonNull(parserResult);
-        if (!parserResult.getMetaData().getGroups().isPresent()) {
+        if (parserResult.getMetaData().getGroups().isEmpty()) {
             return;
         }
 
diff --git a/src/main/java/org/jabref/migrations/ConvertMarkingToGroups.java b/src/main/java/org/jabref/migrations/ConvertMarkingToGroups.java
index 74832a8ca60..5326ae73fca 100644
--- a/src/main/java/org/jabref/migrations/ConvertMarkingToGroups.java
+++ b/src/main/java/org/jabref/migrations/ConvertMarkingToGroups.java
@@ -49,7 +49,7 @@ public void performMigration(ParserResult parserResult) {
                 markingGroup.addEntriesToGroup(markingMatchedEntries);
             }
 
-            if (!parserResult.getMetaData().getGroups().isPresent()) {
+            if (parserResult.getMetaData().getGroups().isEmpty()) {
                 parserResult.getMetaData().setGroups(GroupTreeNode.fromGroup(DefaultGroupsFactory.getAllEntriesGroup()));
             }
             GroupTreeNode root = parserResult.getMetaData().getGroups().get();
@@ -68,7 +68,7 @@ private Multimap<String, BibEntry> getMarkingWithEntries(List<BibEntry> entries)
 
         for (BibEntry entry : entries) {
             Optional<String> marking = entry.getField(InternalField.MARKED_INTERNAL);
-            if (!marking.isPresent()) {
+            if (marking.isEmpty()) {
                 continue;
             }
 
diff --git a/src/main/java/org/jabref/model/util/OptionalUtil.java b/src/main/java/org/jabref/model/util/OptionalUtil.java
index 98034401791..d3610010af6 100644
--- a/src/main/java/org/jabref/model/util/OptionalUtil.java
+++ b/src/main/java/org/jabref/model/util/OptionalUtil.java
@@ -13,8 +13,8 @@
 public class OptionalUtil {
 
     public static <T, U> boolean equals(Optional<T> left, Optional<U> right, BiPredicate<T, U> equality) {
-        if (!left.isPresent()) {
-            return !right.isPresent();
+        if (left.isEmpty()) {
+            return right.isEmpty();
         } else {
             if (right.isPresent()) {
                 return equality.test(left.get(), right.get());
diff --git a/src/main/resources/csl-styles b/src/main/resources/csl-styles
index e328d44b6c1..8bcd8fb2ee3 160000
--- a/src/main/resources/csl-styles
+++ b/src/main/resources/csl-styles
@@ -1 +1 @@
-Subproject commit e328d44b6c1e91f33cf36666bc718141be7d8062
+Subproject commit 8bcd8fb2ee3151e1c5ec2dcf477fa36b26c647c0
diff --git a/src/main/resources/l10n/JabRef_ar.properties b/src/main/resources/l10n/JabRef_ar.properties
index 44275e54d6b..e50ba72a461 100644
--- a/src/main/resources/l10n/JabRef_ar.properties
+++ b/src/main/resources/l10n/JabRef_ar.properties
@@ -373,6 +373,8 @@ Library\ protection=حماية المكتبة
 Unable\ to\ save\ library=تعذر حفظ المكتبة
 
 
+
+
 Please\ open\ or\ start\ a\ new\ library\ before\ searching=الرجاء فتح أو إنشاء مكتبة جديدة قبل البحث
 Please\ enter\ a\ field\ name\ to\ search\ for\ a\ keyword.=الرجاء إدخال اسم الحقل للبحث عن كلمة مفتاحية.
 
diff --git a/src/main/resources/l10n/JabRef_da.properties b/src/main/resources/l10n/JabRef_da.properties
index 234153c4fae..28451149be4 100644
--- a/src/main/resources/l10n/JabRef_da.properties
+++ b/src/main/resources/l10n/JabRef_da.properties
@@ -528,6 +528,8 @@ Character\ encoding\ '%0'\ is\ not\ supported.=Tegnkodingen '%0' er ikke underst
 
 Search=Søg
 Search\ expression=Søgeudtryk
+
+
 Help\ on\ regular\ expression\ search=Hjælp om søgning med regulære udtryk
 Searching\ for\ duplicates...=Søger efter dubletter...
 Searching\ for\ files=Søger efter filer
diff --git a/src/main/resources/l10n/JabRef_de.properties b/src/main/resources/l10n/JabRef_de.properties
index d292c8adbfd..69834bdd70b 100644
--- a/src/main/resources/l10n/JabRef_de.properties
+++ b/src/main/resources/l10n/JabRef_de.properties
@@ -817,6 +817,8 @@ Searching...=Suche läuft...
 Finished\ Searching=Suche beendet
 Search\ expression=Suchausdruck
 Fulltext\ search=Volltextsuche
+
+
 Help\ on\ regular\ expression\ search=Hilfe zur Suche mit regulärem Ausdruck
 Searching\ for\ duplicates...=Suche nach doppelten Einträgen...
 Searching\ for\ files=Suche nach Dateien
diff --git a/src/main/resources/l10n/JabRef_el.properties b/src/main/resources/l10n/JabRef_el.properties
index 2e7ec4c0f82..5fb935d9ea8 100644
--- a/src/main/resources/l10n/JabRef_el.properties
+++ b/src/main/resources/l10n/JabRef_el.properties
@@ -689,6 +689,8 @@ Searching...=Πραγματοποιείται αναζήτηση...
 Finished\ Searching=Ολοκλήρωση Αναζήτησης
 Search\ expression=Αναζήτηση έκφρασης
 Fulltext\ search=Αναζήτηση πλήρους κειμένου
+
+
 Help\ on\ regular\ expression\ search=Βοήθεια για την αναζήτηση κανονικών εκφράσεων
 Searching\ for\ duplicates...=Αναζήτηση για διπλότυπα...
 Searching\ for\ files=Αναζήτηση για αρχεία
diff --git a/src/main/resources/l10n/JabRef_en.properties b/src/main/resources/l10n/JabRef_en.properties
index 2ec8827add2..e7703f1bed7 100644
--- a/src/main/resources/l10n/JabRef_en.properties
+++ b/src/main/resources/l10n/JabRef_en.properties
@@ -819,6 +819,10 @@ Searching...=Searching...
 Finished\ Searching=Finished Searching
 Search\ expression=Search expression
 Fulltext\ search=Fulltext search
+
+Enable\ indexing=Enable indexing
+Fulltext\ search\ requires\ the\ setting\ 'Automatically\ index\ all\ linked\ files\ for\ fulltext\ search'\ to\ be\ enabled.\ Do\ you\ want\ to\ enable\ indexing\ now?=Fulltext search requires the setting 'Automatically index all linked files for fulltext search' to be enabled. Do you want to enable indexing now?
+
 Help\ on\ regular\ expression\ search=Help on regular expression search
 Searching\ for\ duplicates...=Searching for duplicates...
 Searching\ for\ files=Searching for files
diff --git a/src/main/resources/l10n/JabRef_es.properties b/src/main/resources/l10n/JabRef_es.properties
index 510461198e9..a64a92ce6ad 100644
--- a/src/main/resources/l10n/JabRef_es.properties
+++ b/src/main/resources/l10n/JabRef_es.properties
@@ -744,6 +744,8 @@ Searching...=Buscando...
 Finished\ Searching=Terminó la búsqueda
 Search\ expression=Buscar expresión
 Fulltext\ search=Búsqueda de texto completo
+
+
 Help\ on\ regular\ expression\ search=Ayuda sobre búsqueda mediante expresión regular
 Searching\ for\ duplicates...=Buscando duplicados...
 Searching\ for\ files=Buscando archivos
diff --git a/src/main/resources/l10n/JabRef_fa.properties b/src/main/resources/l10n/JabRef_fa.properties
index a579532fa30..586d4e8d17a 100644
--- a/src/main/resources/l10n/JabRef_fa.properties
+++ b/src/main/resources/l10n/JabRef_fa.properties
@@ -328,6 +328,8 @@ Library\ saved=کتابخانه ذخیره شد
 
 
 
+
+
 Search\ results\ from\ open\ libraries=جستجوی نتایج از کتابخانه های باز
 
 
diff --git a/src/main/resources/l10n/JabRef_fi.properties b/src/main/resources/l10n/JabRef_fi.properties
index 66442149920..e44900e6c7a 100644
--- a/src/main/resources/l10n/JabRef_fi.properties
+++ b/src/main/resources/l10n/JabRef_fi.properties
@@ -444,6 +444,8 @@ About\ JabRef=Tietoja JabRef
 
 
 
+
+
 
 
 
diff --git a/src/main/resources/l10n/JabRef_fr.properties b/src/main/resources/l10n/JabRef_fr.properties
index e27271002f1..e4aeac89f96 100644
--- a/src/main/resources/l10n/JabRef_fr.properties
+++ b/src/main/resources/l10n/JabRef_fr.properties
@@ -819,6 +819,10 @@ Searching...=Recherche...
 Finished\ Searching=Recherche terminée
 Search\ expression=Expression à rechercher
 Fulltext\ search=Recherche dans les documents
+
+Enable\ indexing=Activer l'indexation
+Fulltext\ search\ requires\ the\ setting\ 'Automatically\ index\ all\ linked\ files\ for\ fulltext\ search'\ to\ be\ enabled.\ Do\ you\ want\ to\ enable\ indexing\ now?=La recherche dans les documents nécessite le paramètre "Indexer automatiquement tous les fichiers liés pour la recherche dans les documents" pour être activé. Voulez-vous activer l'indexation maintenant ?
+
 Help\ on\ regular\ expression\ search=Aide sur la recherche d'une expression régulière
 Searching\ for\ duplicates...=Recherche des doublons en cours...
 Searching\ for\ files=Recherche de fichiers...
diff --git a/src/main/resources/l10n/JabRef_id.properties b/src/main/resources/l10n/JabRef_id.properties
index 6ee10e99a5f..d6a9aaaba0d 100644
--- a/src/main/resources/l10n/JabRef_id.properties
+++ b/src/main/resources/l10n/JabRef_id.properties
@@ -593,6 +593,8 @@ Search=Cari
 Searching...=Sedang mencari...
 Finished\ Searching=Pencarian Selesai
 Search\ expression=Ekspresi pencarian
+
+
 Help\ on\ regular\ expression\ search=Bantuan untuk Pencarian Ekspresi Reguler
 Searching\ for\ duplicates...=pencarian hal yang sama...
 Searching\ for\ files=Mencari berkas
diff --git a/src/main/resources/l10n/JabRef_it.properties b/src/main/resources/l10n/JabRef_it.properties
index 763c27a48bf..da069c6c15b 100644
--- a/src/main/resources/l10n/JabRef_it.properties
+++ b/src/main/resources/l10n/JabRef_it.properties
@@ -819,6 +819,10 @@ Searching...=Ricerca in corso...
 Finished\ Searching=Ricerca Terminata
 Search\ expression=Espressione di ricerca
 Fulltext\ search=Ricerca su tutto il testo
+
+Enable\ indexing=Abilita indicizzazione
+Fulltext\ search\ requires\ the\ setting\ 'Automatically\ index\ all\ linked\ files\ for\ fulltext\ search'\ to\ be\ enabled.\ Do\ you\ want\ to\ enable\ indexing\ now?=La ricerca di testo completo richiede che l'impostazione 'Indicizza automaticamente tutti i file collegati per la ricerca di testo completo' sia abilitata. Abilitare l'indicizzazione ora?
+
 Help\ on\ regular\ expression\ search=Aiuto sulla ricerca di un'espressione regolare
 Searching\ for\ duplicates...=Ricerca di duplicati in corso...
 Searching\ for\ files=Ricerca dei file
diff --git a/src/main/resources/l10n/JabRef_ja.properties b/src/main/resources/l10n/JabRef_ja.properties
index 42e975a2cd9..08a3fb06e71 100644
--- a/src/main/resources/l10n/JabRef_ja.properties
+++ b/src/main/resources/l10n/JabRef_ja.properties
@@ -705,6 +705,8 @@ Search=検索
 Searching...=検索中...
 Search\ expression=検索表現
 Fulltext\ search=全文検索
+
+
 Help\ on\ regular\ expression\ search=正規表現検索に関するヘルプ
 Searching\ for\ duplicates...=重複を検索しています...
 Searching\ for\ files=ファイルを検索しています
diff --git a/src/main/resources/l10n/JabRef_ko.properties b/src/main/resources/l10n/JabRef_ko.properties
index 331a92dd02e..fcf899f3359 100644
--- a/src/main/resources/l10n/JabRef_ko.properties
+++ b/src/main/resources/l10n/JabRef_ko.properties
@@ -668,6 +668,8 @@ Search=검색
 Searching...=검색 중...
 Search\ expression=수식 검색
 Fulltext\ search=전체 텍스트 검색
+
+
 Help\ on\ regular\ expression\ search=정규식 검색에 대한 도움말
 Searching\ for\ duplicates...=중복 검색 중...
 Searching\ for\ files=파일 검색
diff --git a/src/main/resources/l10n/JabRef_nl.properties b/src/main/resources/l10n/JabRef_nl.properties
index 8b67bace406..a10fa83938b 100644
--- a/src/main/resources/l10n/JabRef_nl.properties
+++ b/src/main/resources/l10n/JabRef_nl.properties
@@ -731,6 +731,8 @@ Searching...=Zoeken...
 Finished\ Searching=Zoeken voltooid
 Search\ expression=Zoek expressie
 Fulltext\ search=Zoeken in de volledige tekst
+
+
 Help\ on\ regular\ expression\ search=Help over Reguliere Expressie Zoekopdracht
 Searching\ for\ duplicates...=Aan het zoeken naar duplicaten...
 Searching\ for\ files=Zoeken naar bestanden
diff --git a/src/main/resources/l10n/JabRef_no.properties b/src/main/resources/l10n/JabRef_no.properties
index 3b5c8239b23..bcee3829e56 100644
--- a/src/main/resources/l10n/JabRef_no.properties
+++ b/src/main/resources/l10n/JabRef_no.properties
@@ -564,6 +564,8 @@ Character\ encoding\ '%0'\ is\ not\ supported.=Tegnkodingen '%0' er ikke støtte
 
 Search=Søk
 Search\ expression=Søkeuttrykk
+
+
 Help\ on\ regular\ expression\ search=Hjelp for søk med regulæruttrykk
 Searching\ for\ duplicates...=Søker etter duplikater...
 Searching\ for\ files=Søker etter filer
diff --git a/src/main/resources/l10n/JabRef_pl.properties b/src/main/resources/l10n/JabRef_pl.properties
index f2afc158336..ff027ad5243 100644
--- a/src/main/resources/l10n/JabRef_pl.properties
+++ b/src/main/resources/l10n/JabRef_pl.properties
@@ -762,6 +762,10 @@ Searching...=Wyszukiwanie...
 Finished\ Searching=Wyszukiwanie zakończone
 Search\ expression=Szukaj wyrażenia
 Fulltext\ search=Wyszukiwanie pełnotekstowe
+
+Enable\ indexing=Włącz indeksowanie
+Fulltext\ search\ requires\ the\ setting\ 'Automatically\ index\ all\ linked\ files\ for\ fulltext\ search'\ to\ be\ enabled.\ Do\ you\ want\ to\ enable\ indexing\ now?=Wyszukiwanie pełnotekstowe wymaga włączenia ustawienia "Automatycznie indeksuj wszystkie powiązane pliki do wyszukiwania pełnotekstowego". Czy chcesz włączyć indeksowanie teraz?
+
 Help\ on\ regular\ expression\ search=Pomoc przy wyszukiwaniu wyrażenia regularnego
 Searching\ for\ duplicates...=Wyszukiwanie duplikatów...
 Searching\ for\ files=Szukanie plików
diff --git a/src/main/resources/l10n/JabRef_pt.properties b/src/main/resources/l10n/JabRef_pt.properties
index f7a4a838b7b..05943b19870 100644
--- a/src/main/resources/l10n/JabRef_pt.properties
+++ b/src/main/resources/l10n/JabRef_pt.properties
@@ -684,6 +684,8 @@ Searching...=Buscando...
 Finished\ Searching=Pesquisa concluída
 Search\ expression=Pesquisar expressão
 Fulltext\ search=Pesquisa de texto completo
+
+
 Help\ on\ regular\ expression\ search=Ajuda sobre busca por expressão regular
 Searching\ for\ duplicates...=Procurando por duplicatas...
 Searching\ for\ files=Procurando por arquivos...
diff --git a/src/main/resources/l10n/JabRef_pt_BR.properties b/src/main/resources/l10n/JabRef_pt_BR.properties
index 924900eb43c..db2dfcfb97b 100644
--- a/src/main/resources/l10n/JabRef_pt_BR.properties
+++ b/src/main/resources/l10n/JabRef_pt_BR.properties
@@ -818,6 +818,10 @@ Searching...=Buscando...
 Finished\ Searching=Pesquisa concluída
 Search\ expression=Pesquisar expressão
 Fulltext\ search=Pesquisa de texto completo
+
+Enable\ indexing=Permitir indexação
+Fulltext\ search\ requires\ the\ setting\ 'Automatically\ index\ all\ linked\ files\ for\ fulltext\ search'\ to\ be\ enabled.\ Do\ you\ want\ to\ enable\ indexing\ now?=Busca por texto completo requer que a configuração 'Automaticamente indexa todos os arquivos vinculados para pesquisa em texto completo' seja ativada. Você deseja ativar a indexação agora?
+
 Help\ on\ regular\ expression\ search=Ajuda sobre busca por expressão regular
 Searching\ for\ duplicates...=Procurando por duplicatas...
 Searching\ for\ files=Procurando por arquivos...
diff --git a/src/main/resources/l10n/JabRef_ru.properties b/src/main/resources/l10n/JabRef_ru.properties
index bbb5fe20c57..efa3fd47af9 100644
--- a/src/main/resources/l10n/JabRef_ru.properties
+++ b/src/main/resources/l10n/JabRef_ru.properties
@@ -720,6 +720,8 @@ Search=Поиск
 Searching...=Выполняется поиск...
 Search\ expression=Выражение для поиска
 Fulltext\ search=Полнотекстовый поиск
+
+
 Help\ on\ regular\ expression\ search=Справка по поиску с помощью регулярных выражений
 Searching\ for\ duplicates...=Выполняется поиск дубликатов...
 Searching\ for\ files=Выполняется поиск файлов...
diff --git a/src/main/resources/l10n/JabRef_sv.properties b/src/main/resources/l10n/JabRef_sv.properties
index 25ee8df12dd..f6efad2fb81 100644
--- a/src/main/resources/l10n/JabRef_sv.properties
+++ b/src/main/resources/l10n/JabRef_sv.properties
@@ -623,6 +623,8 @@ Character\ encoding\ '%0'\ is\ not\ supported.=Teckenkodningen '%0' stöds inte.
 Search=Sök
 Searching...=Söker...
 Search\ expression=Sökuttryck
+
+
 Help\ on\ regular\ expression\ search=Hjälp för sökning med reguljära uttryck
 Searching\ for\ duplicates...=Söker efter dubbletter...
 Searching\ for\ files=Söker efter filer
diff --git a/src/main/resources/l10n/JabRef_tl.properties b/src/main/resources/l10n/JabRef_tl.properties
index 8fbeea796c8..47ece682433 100644
--- a/src/main/resources/l10n/JabRef_tl.properties
+++ b/src/main/resources/l10n/JabRef_tl.properties
@@ -557,6 +557,8 @@ Character\ encoding\ '%0'\ is\ not\ supported.=Pagkod ng mga Karakter '%0' ay hi
 Search=Ang paghahanap
 Searching...=Naghahanap...
 Search\ expression=Hanapin ang ekspresyon
+
+
 Help\ on\ regular\ expression\ search=Tumulong sa regular na paghahanap sa ekspresyon
 Searching\ for\ duplicates...=Naghahanap ng kakopya...
 Searching\ for\ files=Naghahanap nga mga files
diff --git a/src/main/resources/l10n/JabRef_tr.properties b/src/main/resources/l10n/JabRef_tr.properties
index a751e569474..5989566e1a3 100644
--- a/src/main/resources/l10n/JabRef_tr.properties
+++ b/src/main/resources/l10n/JabRef_tr.properties
@@ -741,6 +741,8 @@ Searching...=Arıyor...
 Finished\ Searching=Arama Bitti
 Search\ expression=İfade ara
 Fulltext\ search=Tam metin arama
+
+
 Help\ on\ regular\ expression\ search=Düzenli İfade Arama hakkında yardım
 Searching\ for\ duplicates...=Çift nüshalar aranıyor...
 Searching\ for\ files=Dosyalar aranıyor
diff --git a/src/main/resources/l10n/JabRef_uk.properties b/src/main/resources/l10n/JabRef_uk.properties
index 2d6106c3c6a..640e71c8eb3 100644
--- a/src/main/resources/l10n/JabRef_uk.properties
+++ b/src/main/resources/l10n/JabRef_uk.properties
@@ -511,6 +511,8 @@ Current\ value\:\ %0=Поточне значення\: %0
 
 
 
+
+
 
 
 
diff --git a/src/main/resources/l10n/JabRef_vi.properties b/src/main/resources/l10n/JabRef_vi.properties
index 1d86d63f878..830ed5fd1a4 100644
--- a/src/main/resources/l10n/JabRef_vi.properties
+++ b/src/main/resources/l10n/JabRef_vi.properties
@@ -562,6 +562,8 @@ Character\ encoding\ '%0'\ is\ not\ supported.=Mã hóa ký tự '%0' không đ
 
 Search=Tìm
 Search\ expression=Biểu thức tìm kiếm
+
+
 Help\ on\ regular\ expression\ search=Trợ giúp về tìm kiếm bằng biểu thức chính tắc
 Searching\ for\ duplicates...=Đang tìm các mục bị lặp...
 Searching\ for\ files=Đang tìm các tập tin
diff --git a/src/main/resources/l10n/JabRef_zh_CN.properties b/src/main/resources/l10n/JabRef_zh_CN.properties
index 5c1970d7b26..4d70f95edd3 100644
--- a/src/main/resources/l10n/JabRef_zh_CN.properties
+++ b/src/main/resources/l10n/JabRef_zh_CN.properties
@@ -724,6 +724,8 @@ Searching...=正在搜索...
 Finished\ Searching=搜索完成
 Search\ expression=查找表达式
 Fulltext\ search=全文搜索
+
+
 Help\ on\ regular\ expression\ search=正则表达式搜索帮助
 Searching\ for\ duplicates...=正在查找重复记录...
 Searching\ for\ files=正在查找文件
diff --git a/src/main/resources/l10n/JabRef_zh_TW.properties b/src/main/resources/l10n/JabRef_zh_TW.properties
index 48b91b8829d..31b0daf5435 100644
--- a/src/main/resources/l10n/JabRef_zh_TW.properties
+++ b/src/main/resources/l10n/JabRef_zh_TW.properties
@@ -523,6 +523,8 @@ Unable\ to\ save\ library=無法儲存文獻倉庫
 Character\ encoding\ '%0'\ is\ not\ supported.=，不支援「%0」編碼。
 
 Search=搜尋
+
+
 Help\ on\ regular\ expression\ search=正規表達式搜索幫助
 Web\ search=網頁搜尋
 
diff --git a/src/test/java/org/jabref/logic/importer/fetcher/BvbFetcherTest.java b/src/test/java/org/jabref/logic/importer/fetcher/BvbFetcherTest.java
index c478693330b..e1d08456fd4 100644
--- a/src/test/java/org/jabref/logic/importer/fetcher/BvbFetcherTest.java
+++ b/src/test/java/org/jabref/logic/importer/fetcher/BvbFetcherTest.java
@@ -5,14 +5,15 @@
 import java.util.List;
 
 import org.jabref.logic.importer.FetcherException;
+import org.jabref.logic.util.StandardFileType;
 import org.jabref.model.entry.BibEntry;
+import org.jabref.model.entry.LinkedFile;
 import org.jabref.model.entry.field.StandardField;
 import org.jabref.model.entry.types.StandardEntryType;
 import org.jabref.testutils.category.FetcherTest;
 
 import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
 import org.apache.lucene.queryparser.flexible.standard.parser.StandardSyntaxParser;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import static org.jabref.logic.importer.fetcher.transformers.AbstractQueryTransformer.NO_EXPLICIT_FIELD;
@@ -23,8 +24,30 @@
 class BvbFetcherTest {
 
     BvbFetcher fetcher = new BvbFetcher();
-    BibEntry bibEntryISBN0134685997;
-    BibEntry bibEntryISBN9783960886402;
+    BibEntry bibEntryISBN9783960886402 = new BibEntry(StandardEntryType.Misc)
+            .withField(StandardField.TITLE, "Effective Java")
+            .withField(StandardField.YEAR, "2018")
+            .withField(StandardField.SUBTITLE, "best practices für die Java-Plattform")
+            .withField(StandardField.AUTHOR, "Bloch, Joshua")
+            .withField(StandardField.TITLEADDON, "Joshua Bloch")
+            .withField(StandardField.EDITION, "3. Auflage, Übersetzung der englischsprachigen 3. Originalausgabe 2018")
+            .withFiles(List.of(new LinkedFile("", "http://search.ebscohost.com/login.aspx?direct=true&scope=site&db=nlebk&db=nlabk&AN=1906353", StandardFileType.PDF)))
+            .withField(StandardField.ISBN, "9783960886402")
+            .withField(StandardField.KEYWORDS, "Klassen, Interfaces, Generics, Enums, Annotationen, Lambdas, Streams, Module, parallel, Parallele Programmierung, Serialisierung, funktional, funktionale Programmierung, Java EE, Jakarta EE")
+            .withField(StandardField.ADDRESS, "Heidelberg")
+            .withField(StandardField.PAGETOTAL, "396")
+            .withField(StandardField.PUBLISHER, "{dpunkt.verlag} and {Dpunkt. Verlag (Heidelberg)}");
+
+    BibEntry bibEntryISBN0134685997 = new BibEntry(StandardEntryType.Misc)
+            .withField(StandardField.TITLE, "Effective Java")
+            .withField(StandardField.YEAR, "2018")
+            .withField(StandardField.AUTHOR, "Bloch, Joshua")
+            .withField(StandardField.TITLEADDON, "Joshua Bloch")
+            .withField(StandardField.EDITION, "Third edition")
+            .withField(StandardField.ISBN, "0134685997")
+            .withField(StandardField.PAGETOTAL, "392")
+            .withField(StandardField.ADDRESS, "Boston")
+            .withField(StandardField.PUBLISHER, "{Addison-Wesley}");
 
     @Test
     void performTest() throws Exception {
@@ -38,41 +61,6 @@ void performTest() throws Exception {
 //        result.forEach(entry -> System.out.println(entry.toString()));
     }
 
-    @BeforeEach
-    void setUp() {
-        fetcher = new BvbFetcher();
-
-        bibEntryISBN9783960886402 = new BibEntry(StandardEntryType.Misc)
-                .withField(StandardField.TITLE, "Effective Java")
-                .withField(StandardField.YEAR, "2018")
-                .withField(StandardField.SUBTITLE, "best practices für die Java-Plattform")
-                .withField(StandardField.AUTHOR, "Bloch, Joshua")
-                .withField(StandardField.TITLEADDON, "Joshua Bloch")
-                .withField(StandardField.EDITION, "3. Auflage, Übersetzung der englischsprachigen 3. Originalausgabe 2018")
-                .withField(StandardField.FILE, "ParsedFileField{description='', link='http://search.ebscohost.com/login.aspx?direct=true&scope=site&db=nlebk&db=nlabk&AN=1906353', fileType='PDF'}")
-                .withField(StandardField.ISBN, "9783960886402")
-                .withField(StandardField.KEYWORDS, "Klassen, Interfaces, Generics, Enums, Annotationen, Lambdas, Streams, Module, parallel, Parallele Programmierung, Serialisierung, funktional, funktionale Programmierung, Java EE, Jakarta EE")
-                .withField(StandardField.ADDRESS, "Heidelberg")
-                .withField(StandardField.PAGETOTAL, "396")
-                .withField(StandardField.PUBLISHER, "{dpunkt.verlag} and {Dpunkt. Verlag (Heidelberg)}");
-
-        bibEntryISBN0134685997 = new BibEntry(StandardEntryType.Misc)
-                .withField(StandardField.TITLE, "Effective Java")
-                .withField(StandardField.YEAR, "2018")
-                .withField(StandardField.AUTHOR, "Bloch, Joshua")
-                .withField(StandardField.TITLEADDON, "Joshua Bloch")
-                .withField(StandardField.EDITION, "Third edition")
-                .withField(StandardField.ISBN, "0134685997")
-                .withField(StandardField.PAGETOTAL, "392")
-                .withField(StandardField.ADDRESS, "Boston")
-                .withField(StandardField.PUBLISHER, "{Addison-Wesley}");
-    }
-
-    @Test
-    void getName() {
-        assertEquals("Bibliotheksverbund Bayern (Experimental)", fetcher.getName());
-    }
-
     @Test
     void simpleSearchQueryURLCorrect() throws Exception {
         String query = "java jdk";
@@ -92,8 +80,7 @@ void complexSearchQueryURLCorrect() throws Exception {
     @Test
     void performSearchMatchingMultipleEntries() throws FetcherException {
         List<BibEntry> searchResult = fetcher.performSearch("effective java bloch");
-        assertEquals(bibEntryISBN9783960886402, searchResult.getFirst());
-        assertEquals(bibEntryISBN0134685997, searchResult.get(1));
+        assertEquals(List.of(bibEntryISBN9783960886402, bibEntryISBN0134685997), searchResult.subList(0, 2));
     }
 
     @Test