Revert java 9 usage with java 8 equivalent

extractor/src/main/java/org/schabi/newpipe/extractor/ServiceList.java

@@ -6,6 +6,7 @@
 import org.schabi.newpipe.extractor.services.soundcloud.SoundcloudService;
 import org.schabi.newpipe.extractor.services.youtube.YoutubeService;
 
+import java.util.Arrays;
 import java.util.List;
 
 /*
@@ -45,7 +46,7 @@ private ServiceList() {
      * When creating a new service, put this service in the end of this list,
      * and give it the next free id.
      */
-    private static final List<StreamingService> SERVICES = List.of(
+    private static final List<StreamingService> SERVICES = Arrays.asList(
             YouTube, SoundCloud, MediaCCC, PeerTube, Bandcamp);
 
     /**

extractor/src/main/java/org/schabi/newpipe/extractor/services/bandcamp/extractors/BandcampCommentsExtractor.java

@@ -22,6 +22,7 @@
 import org.schabi.newpipe.extractor.utils.JsonUtils;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
@@ -67,7 +68,7 @@ public InfoItemsPage<CommentsInfoItem> getInitialPage()
 
         final String trackId = getTrackId();
         final String token = getNextPageToken(reviews);
-        return new InfoItemsPage<>(collector, new Page(List.of(trackId, token)));
+        return new InfoItemsPage<>(collector, new Page(Arrays.asList(trackId, token)));
     }
 
     @Override
@@ -92,7 +93,7 @@ public InfoItemsPage<CommentsInfoItem> getPage(final Page page)
         }
 
         return new InfoItemsPage<>(collector,
-                new Page(List.of(trackId, getNextPageToken(reviews))));
+                new Page(Arrays.asList(trackId, getNextPageToken(reviews))));
     }
 
     private JsonObject fetchReviewsData(final String trackId, final String token)

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeSuggestionExtractor.java

@@ -86,7 +86,7 @@ public List<String> suggestionList(final String query) throws IOException, Extra
                     .map(JsonArray.class::cast)
                     .map(suggestion -> suggestion.getString(0)) // 0 is the search suggestion
                     .filter(suggestion -> !isBlank(suggestion)) // Filter blank suggestions
-                    .collect(Collectors.toUnmodifiableList());
+                    .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList));
         } catch (final JsonParserException e) {
             throw new ParsingException("Could not parse JSON response", e);
         }

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeTrendingExtractor.java

@@ -134,7 +134,7 @@ public InfoItemsPage<StreamInfoItem> getInitialPage() throws ParsingException {
             final Stream<JsonObject> items;
             if (isVideoTab) {
                 // The first shelf of the Videos tab contains the normal trends
-                items = shelves.findFirst().stream();
+                items = shelves.findFirst().isPresent() ? Stream.of(shelves.findFirst().get()) : Stream.empty();
             } else {
                 // Filter Trending shorts and Recently trending sections which have a title,
                 // contrary to normal trends

extractor/src/test/java/org/schabi/newpipe/extractor/services/bandcamp/BandcampPaidStreamExtractorTest.java

@@ -9,6 +9,7 @@
 import org.schabi.newpipe.extractor.NewPipe;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
 import org.schabi.newpipe.extractor.exceptions.PaidContentException;
+import org.schabi.newpipe.extractor.stream.StreamExtractor;
 
 public class BandcampPaidStreamExtractorTest {
 
@@ -19,7 +20,7 @@ public static void setUp() {
 
     @Test
     public void testPaidTrack() throws ExtractionException {
-        final var extractor = Bandcamp.getStreamExtractor("https://radicaldreamland.bandcamp.com/track/hackmud-continuous-mix");
+        final StreamExtractor extractor = Bandcamp.getStreamExtractor("https://radicaldreamland.bandcamp.com/track/hackmud-continuous-mix");
         assertThrows(PaidContentException.class, extractor::fetchPage);
     }
 }

extractor/src/test/java/org/schabi/newpipe/extractor/services/youtube/stream/YoutubeStreamExtractorDefaultTest.java

@@ -418,9 +418,9 @@ public static void setUp() throws Exception {
                     "",
                     new Description("Arte is a French/German public broadcast service.",
                             Description.PLAIN_TEXT),
-                    List.of(new URL(
+                    Collections.singletonList(new URL(
                             "https://en.wikipedia.org/wiki/Arte?wprov=yicw1")),
-                    List.of("Wikipedia")
+                    Collections.singletonList("Wikipedia")
             ));
         }
         @Override public boolean expectedUploaderVerified() { return true; }