diff --git a/build.gradle b/build.gradle
index a9197df67..e54215a4b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -24,4 +24,12 @@ task sourcesJar(type: Jar, dependsOn: classes) {
 
 artifacts {
     archives sourcesJar
+}
+
+tasks.withType(Test) {
+    testLogging {
+        events "skipped", "failed"
+        showStandardStreams = true
+        exceptionFormat = 'full'
+    }
 }
\ No newline at end of file
diff --git a/src/main/java/org/schabi/newpipe/extractor/Extractor.java b/src/main/java/org/schabi/newpipe/extractor/Extractor.java
index 3e0456a94..e71321836 100644
--- a/src/main/java/org/schabi/newpipe/extractor/Extractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/Extractor.java
@@ -33,12 +33,16 @@ public abstract class Extractor {
      */
     @Nullable
     private String cleanUrl;
+    private boolean pageFetched = false;
+    private final Downloader downloader;
 
     public Extractor(StreamingService service, String url) throws ExtractionException {
         if(service == null) throw new NullPointerException("service is null");
         if(url == null) throw new NullPointerException("url is null");
         this.service = service;
         this.originalUrl = url;
+        this.downloader = NewPipe.getDownloader();
+        if(downloader == null) throw new NullPointerException("downloader is null");
     }
 
     /**
@@ -49,8 +53,26 @@ public abstract class Extractor {
 
     /**
      * Fetch the current page.
+     * @throws IOException if the page can not be loaded
+     * @throws ExtractionException if the pages content is not understood
      */
-    public abstract void fetchPage() throws IOException, ExtractionException;
+    public void fetchPage() throws IOException, ExtractionException {
+        if(pageFetched) return;
+        onFetchPage(downloader);
+        pageFetched = true;
+    }
+
+    protected void assertPageFetched() {
+        if(!pageFetched) throw new IllegalStateException("Page is not fetched. Make sure you call fetchPage()");
+    }
+
+    /**
+     * Fetch the current page.
+     * @param downloader the download to use
+     * @throws IOException if the page can not be loaded
+     * @throws ExtractionException if the pages content is not understood
+     */
+    public abstract void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException;
 
     @Nonnull
     public abstract String getId() throws ParsingException;
diff --git a/src/main/java/org/schabi/newpipe/extractor/Info.java b/src/main/java/org/schabi/newpipe/extractor/Info.java
index c2445bd61..8e9fc79d0 100644
--- a/src/main/java/org/schabi/newpipe/extractor/Info.java
+++ b/src/main/java/org/schabi/newpipe/extractor/Info.java
@@ -16,7 +16,7 @@ public abstract class Info implements Serializable {
     public final String url;
     public final String name;
 
-    public List<Throwable> errors = new ArrayList<>();
+    public final List<Throwable> errors = new ArrayList<>();
 
     public void addError(Throwable throwable) {
         this.errors.add(throwable);
diff --git a/src/main/java/org/schabi/newpipe/extractor/Subtitles.java b/src/main/java/org/schabi/newpipe/extractor/Subtitles.java
index 0542b385e..9427bf528 100644
--- a/src/main/java/org/schabi/newpipe/extractor/Subtitles.java
+++ b/src/main/java/org/schabi/newpipe/extractor/Subtitles.java
@@ -3,9 +3,10 @@ package org.schabi.newpipe.extractor;
 import org.schabi.newpipe.extractor.stream.SubtitlesFormat;
 
 public class Subtitles {
-    private SubtitlesFormat format;
-    private String languageCode, URL;
-    private boolean autoGenerated;
+    private final SubtitlesFormat format;
+    private final String languageCode;
+    private final String URL;
+    private final boolean autoGenerated;
 
     public Subtitles(SubtitlesFormat format, String languageCode, String URL, boolean autoGenerated) {
         this.format = format;
diff --git a/src/main/java/org/schabi/newpipe/extractor/SuggestionExtractor.java b/src/main/java/org/schabi/newpipe/extractor/SuggestionExtractor.java
index 983adc07e..d7c9cdca7 100644
--- a/src/main/java/org/schabi/newpipe/extractor/SuggestionExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/SuggestionExtractor.java
@@ -27,7 +27,7 @@ import java.util.List;
 
 public abstract class SuggestionExtractor {
 
-    private int serviceId;
+    private final int serviceId;
 
     public SuggestionExtractor(int serviceId) {
         this.serviceId = serviceId;
diff --git a/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskExtractor.java b/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskExtractor.java
index 5df579e7a..923f5d033 100644
--- a/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskExtractor.java
@@ -30,7 +30,7 @@ import java.io.IOException;
 
 public abstract class KioskExtractor extends ListExtractor {
     private String contentCountry = null;
-    private String id = null;
+    private final String id;
 
     public KioskExtractor(StreamingService streamingService,
                           String url,
diff --git a/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskList.java b/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskList.java
index bbaab0092..5256af8e0 100644
--- a/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskList.java
+++ b/src/main/java/org/schabi/newpipe/extractor/kiosk/KioskList.java
@@ -19,8 +19,8 @@ public  class KioskList {
             throws ExtractionException, IOException;
     }
 
-    private int service_id;
-    private HashMap<String, KioskEntry> kioskList = new HashMap<>();
+    private final int service_id;
+    private final HashMap<String, KioskEntry> kioskList = new HashMap<>();
     private String defaultKiosk = null;
 
     private class KioskEntry {
@@ -28,8 +28,8 @@ public  class KioskList {
             extractorFactory = ef;
             handler = h;
         }
-        KioskExtractorFactory extractorFactory;
-        UrlIdHandler handler;
+        final KioskExtractorFactory extractorFactory;
+        final UrlIdHandler handler;
     }
 
     public KioskList(int service_id) {
diff --git a/src/main/java/org/schabi/newpipe/extractor/search/SearchEngine.java b/src/main/java/org/schabi/newpipe/extractor/search/SearchEngine.java
index b9f9fa393..878888324 100644
--- a/src/main/java/org/schabi/newpipe/extractor/search/SearchEngine.java
+++ b/src/main/java/org/schabi/newpipe/extractor/search/SearchEngine.java
@@ -35,7 +35,7 @@ public abstract class SearchEngine {
         }
     }
 
-    private InfoItemSearchCollector collector;
+    private final InfoItemSearchCollector collector;
 
     public SearchEngine(int serviceId) {
         collector = new InfoItemSearchCollector(serviceId);
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelExtractor.java
index 845d77217..e81fe2cb1 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelExtractor.java
@@ -24,14 +24,13 @@ public class SoundcloudChannelExtractor extends ChannelExtractor {
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        Downloader dl = NewPipe.getDownloader();
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
 
         userId = getUrlIdHandler().getId(getOriginalUrl());
         String apiUrl = "https://api.soundcloud.com/users/" + userId +
                 "?client_id=" + SoundcloudParsingHelper.clientId();
 
-        String response = dl.download(apiUrl);
+        String response = downloader.download(apiUrl);
         try {
             user = JsonParser.object().from(response);
         } catch (JsonParserException e) {
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelInfoItemExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelInfoItemExtractor.java
index 773e8e405..532c059b8 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelInfoItemExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChannelInfoItemExtractor.java
@@ -4,7 +4,7 @@ import com.grack.nanojson.JsonObject;
 import org.schabi.newpipe.extractor.channel.ChannelInfoItemExtractor;
 
 public class SoundcloudChannelInfoItemExtractor implements ChannelInfoItemExtractor {
-    private JsonObject searchResult;
+    private final JsonObject searchResult;
 
     public SoundcloudChannelInfoItemExtractor(JsonObject searchResult) {
         this.searchResult = searchResult;
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChartsExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChartsExtractor.java
index 24e51b1ac..ac5f933bc 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChartsExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudChartsExtractor.java
@@ -4,6 +4,7 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
+import org.schabi.newpipe.extractor.Downloader;
 import org.schabi.newpipe.extractor.StreamingService;
 import org.schabi.newpipe.extractor.UrlIdHandler;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
@@ -23,7 +24,7 @@ public class SoundcloudChartsExtractor extends KioskExtractor {
     }
 
     @Override
-    public void fetchPage() {
+    public void onFetchPage(@Nonnull Downloader downloader) {
     }
 
     @Nonnull
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java
index d2381bc5f..f68fff07a 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java
@@ -67,13 +67,13 @@ public class SoundcloudParsingHelper {
      * 
      * See https://developers.soundcloud.com/docs/api/reference#resolve
      */
-    public static JsonObject resolveFor(String url) throws IOException, ReCaptchaException, ParsingException {
+    public static JsonObject resolveFor(Downloader downloader, String url) throws IOException, ReCaptchaException, ParsingException {
         String apiUrl = "https://api.soundcloud.com/resolve"
                 + "?url=" + URLEncoder.encode(url, "UTF-8")
                 + "&client_id=" + clientId();
 
         try {
-            return JsonParser.object().from(NewPipe.getDownloader().download(apiUrl));
+            return JsonParser.object().from(downloader.download(apiUrl));
         } catch (JsonParserException e) {
             throw new ParsingException("Could not parse json response", e);
         }
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistExtractor.java
index 3f51be7c3..35da76425 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistExtractor.java
@@ -24,15 +24,14 @@ public class SoundcloudPlaylistExtractor extends PlaylistExtractor {
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        Downloader dl = NewPipe.getDownloader();
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
 
         playlistId = getUrlIdHandler().getId(getOriginalUrl());
         String apiUrl = "https://api.soundcloud.com/playlists/" + playlistId +
                 "?client_id=" + SoundcloudParsingHelper.clientId() +
                 "&representation=compact";
 
-        String response = dl.download(apiUrl);
+        String response = downloader.download(apiUrl);
         try {
             playlist = JsonParser.object().from(response);
         } catch (JsonParserException e) {
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistInfoItemExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistInfoItemExtractor.java
index 6002f054e..276f2c6a5 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistInfoItemExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistInfoItemExtractor.java
@@ -9,7 +9,7 @@ public class SoundcloudPlaylistInfoItemExtractor implements PlaylistInfoItemExtr
     private static final String AVATAR_URL_KEY = "avatar_url";
     private static final String ARTWORK_URL_KEY = "artwork_url";
 
-    private JsonObject searchResult;
+    private final JsonObject searchResult;
 
     public SoundcloudPlaylistInfoItemExtractor(JsonObject searchResult) {
         this.searchResult = searchResult;
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractor.java
index d323a262c..ca02b7a0c 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractor.java
@@ -21,12 +21,11 @@ public class SoundcloudStreamExtractor extends StreamExtractor {
 
     public SoundcloudStreamExtractor(StreamingService service, String url) throws IOException, ExtractionException {
         super(service, url);
-        fetchPage();
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        track = SoundcloudParsingHelper.resolveFor(getOriginalUrl());
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
+        track = SoundcloudParsingHelper.resolveFor(downloader, getOriginalUrl());
 
         String policy = track.getString("policy", "");
         if (!policy.equals("ALLOW") && !policy.equals("MONETIZE")) {
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/ItagItem.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/ItagItem.java
index 9d9663de3..1950c0b5e 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/ItagItem.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/ItagItem.java
@@ -146,8 +146,8 @@ public class ItagItem {
         return mediaFormat;
     }
 
-    public int id;
-    public ItagType itagType;
+    public final int id;
+    public final ItagType itagType;
 
     // Audio fields
     public int avgBitrate = -1;
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelExtractor.java
index 054e6d798..d1b9ae165 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelExtractor.java
@@ -59,9 +59,7 @@ public class YoutubeChannelExtractor extends ChannelExtractor {
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        Downloader downloader = NewPipe.getDownloader();
-
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
         String channelUrl = super.getCleanUrl() + CHANNEL_URL_PARAMETERS;
         String pageContent = downloader.download(channelUrl);
         doc = Jsoup.parse(pageContent, channelUrl);
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelInfoItemExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelInfoItemExtractor.java
index d6d5d4620..a04d85622 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelInfoItemExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelInfoItemExtractor.java
@@ -26,7 +26,7 @@ import org.schabi.newpipe.extractor.utils.Utils;
  */
 
 public class YoutubeChannelInfoItemExtractor implements ChannelInfoItemExtractor {
-    private Element el;
+    private final Element el;
 
     public YoutubeChannelInfoItemExtractor(Element el) {
         this.el = el;
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistExtractor.java
index 02619fc6e..c6e5c064d 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistExtractor.java
@@ -36,9 +36,7 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        Downloader downloader = NewPipe.getDownloader();
-
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
         String pageContent = downloader.download(getCleanUrl());
         doc = Jsoup.parse(pageContent, getCleanUrl());
 
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistInfoItemExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistInfoItemExtractor.java
index 552f58f41..fe6e7768f 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistInfoItemExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistInfoItemExtractor.java
@@ -6,7 +6,7 @@ import org.schabi.newpipe.extractor.playlist.PlaylistInfoItemExtractor;
 import org.schabi.newpipe.extractor.utils.Utils;
 
 public class YoutubePlaylistInfoItemExtractor implements PlaylistInfoItemExtractor {
-    private Element el;
+    private final Element el;
 
     public YoutubePlaylistInfoItemExtractor(Element el) {
         this.el = el;
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractor.java
index 515af7483..66e72ef29 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractor.java
@@ -86,7 +86,6 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     public YoutubeStreamExtractor(StreamingService service, String url) throws IOException, ExtractionException {
         super(service, url);
-        fetchPage();
     }
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -106,6 +105,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getName() throws ParsingException {
+        assertPageFetched();
         String name = getStringFromMetaData("title");
         if(name == null) {
             // Fallback to HTML method
@@ -124,6 +124,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getUploadDate() throws ParsingException {
+        assertPageFetched();
         try {
             return doc.select("meta[itemprop=datePublished]").attr(CONTENT);
         } catch (Exception e) {//todo: add fallback method
@@ -134,6 +135,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getThumbnailUrl() throws ParsingException {
+        assertPageFetched();
         // Try to get high resolution thumbnail first, if it fails, use low res from the player instead
         try {
             return doc.select("link[itemprop=\"thumbnailUrl\"]").first().attr("abs:href");
@@ -157,6 +159,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getDescription() throws ParsingException {
+        assertPageFetched();
         try {
             return doc.select("p[id=\"eow-description\"]").first().html();
         } catch (Exception e) {//todo: add fallback method <-- there is no ... as long as i know
@@ -166,6 +169,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public int getAgeLimit() throws ParsingException {
+        assertPageFetched();
         if (!isAgeRestricted) {
             return NO_AGE_LIMIT;
         }
@@ -179,6 +183,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public long getLength() throws ParsingException {
+        assertPageFetched();
         if(playerArgs != null) {
             try {
                 long returnValue = Long.parseLong(playerArgs.get("length_seconds") + "");
@@ -217,6 +222,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public long getViewCount() throws ParsingException {
+        assertPageFetched();
         try {
             return Long.parseLong(doc.select("meta[itemprop=interactionCount]").attr(CONTENT));
         } catch (Exception e) {//todo: find fallback method
@@ -226,6 +232,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public long getLikeCount() throws ParsingException {
+        assertPageFetched();
         String likesString = "";
         try {
             Element button = doc.select("button.like-button-renderer-like-button").first();
@@ -245,6 +252,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public long getDislikeCount() throws ParsingException {
+        assertPageFetched();
         String dislikesString = "";
         try {
             Element button = doc.select("button.like-button-renderer-dislike-button").first();
@@ -265,6 +273,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getUploaderUrl() throws ParsingException {
+        assertPageFetched();
         try {
             return doc.select("div[class=\"yt-user-info\"]").first().children()
                     .select("a").first().attr("abs:href");
@@ -276,6 +285,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Nullable
     private String getStringFromMetaData(String field) {
+        assertPageFetched();
         String value = null;
         if(playerArgs != null) {
             // This can not fail
@@ -291,6 +301,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getUploaderName() throws ParsingException {
+        assertPageFetched();
         String name = getStringFromMetaData("author");
 
         if(name == null) {
@@ -310,6 +321,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Nonnull
     @Override
     public String getUploaderAvatarUrl() throws ParsingException {
+        assertPageFetched();
         try {
             return doc.select("a[class*=\"yt-user-photo\"]").first()
                     .select("img").first()
@@ -321,6 +333,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public String getDashMpdUrl() throws ParsingException {
+        assertPageFetched();
         try {
             String dashManifestUrl;
             if (videoInfoPage.containsKey("dashmpd")) {
@@ -347,6 +360,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public List<AudioStream> getAudioStreams() throws IOException, ExtractionException {
+        assertPageFetched();
         List<AudioStream> audioStreams = new ArrayList<>();
         try {
             for (Map.Entry<String, ItagItem> entry : getItags(ADAPTIVE_FMTS, ItagItem.ItagType.AUDIO).entrySet()) {
@@ -366,6 +380,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public List<VideoStream> getVideoStreams() throws IOException, ExtractionException {
+        assertPageFetched();
         List<VideoStream> videoStreams = new ArrayList<>();
         try {
             for (Map.Entry<String, ItagItem> entry : getItags(URL_ENCODED_FMT_STREAM_MAP, ItagItem.ItagType.VIDEO).entrySet()) {
@@ -385,6 +400,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public List<VideoStream> getVideoOnlyStreams() throws IOException, ExtractionException {
+        assertPageFetched();
         List<VideoStream> videoOnlyStreams = new ArrayList<>();
         try {
             for (Map.Entry<String, ItagItem> entry : getItags(ADAPTIVE_FMTS, ItagItem.ItagType.VIDEO_ONLY).entrySet()) {
@@ -411,11 +427,13 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     @Override
     @Nullable
     public List<Subtitles> getSubtitles(SubtitlesFormat format) throws IOException, ExtractionException {
+        assertPageFetched();
         if(isAgeRestricted) {
             // If the video is age restricted getPlayerConfig will fail
             return null;
         }
-        JsonObject playerConfig = getPlayerConfig(getPageHtml());
+        // TODO: This should be done in onFetchPage()
+        JsonObject playerConfig = getPlayerConfig(getPageHtml(NewPipe.getDownloader()));
         String playerResponse = playerConfig.getObject("args").getString("player_response");
 
         JsonObject captions;
@@ -459,6 +477,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public StreamInfoItem getNextVideo() throws IOException, ExtractionException {
+        assertPageFetched();
         try {
             StreamInfoItemCollector collector = new StreamInfoItemCollector(getServiceId());
             collector.commit(extractVideoPreviewInfo(doc.select("div[class=\"watch-sidebar-section\"]")
@@ -472,6 +491,7 @@ public class YoutubeStreamExtractor extends StreamExtractor {
 
     @Override
     public StreamInfoItemCollector getRelatedVideos() throws IOException, ExtractionException {
+        assertPageFetched();
         try {
             StreamInfoItemCollector collector = new StreamInfoItemCollector(getServiceId());
             Element ul = doc.select("ul[id=\"watch-related\"]").first();
@@ -526,30 +546,27 @@ public class YoutubeStreamExtractor extends StreamExtractor {
     private static final String GET_VIDEO_INFO_URL = "https://www.youtube.com/get_video_info?video_id=" + "%s" +
             "&el=info&ps=default&eurl=&gl=US&hl=en";
 
-    private static volatile String decryptionCode = "";
+    private volatile String decryptionCode = "";
 
-    private static String pageHtml = null;
+    private String pageHtml = null;
 
-    private String getPageHtml() throws IOException, ExtractionException{
+    private String getPageHtml(Downloader downloader) throws IOException, ExtractionException{
         if (pageHtml == null) {
-            Downloader dl = NewPipe.getDownloader();
-            pageHtml = dl.download(getCleanUrl());
+            pageHtml = downloader.download(getCleanUrl());
         }
         return pageHtml;
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        Downloader dl = NewPipe.getDownloader();
-
-        String pageContent = getPageHtml();
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
+        String pageContent = getPageHtml(downloader);
         doc = Jsoup.parse(pageContent, getCleanUrl());
 
 
         String playerUrl;
         // Check if the video is age restricted
         if (pageContent.contains("<meta property=\"og:restrictions:age")) {
-            String infoPageResponse = dl.download(String.format(GET_VIDEO_INFO_URL, getId()));
+            String infoPageResponse = downloader.download(String.format(GET_VIDEO_INFO_URL, getId()));
             videoInfoPage.putAll(Parser.compatParseMap(infoPageResponse));
             playerUrl = getPlayerUrlFromRestrictedVideo();
             isAgeRestricted = true;
diff --git a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractor.java b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractor.java
index efc9a3e7a..e6ff345d7 100644
--- a/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractor.java
+++ b/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractor.java
@@ -42,9 +42,7 @@ public class YoutubeTrendingExtractor extends KioskExtractor {
     }
 
     @Override
-    public void fetchPage() throws IOException, ExtractionException {
-        Downloader downloader = NewPipe.getDownloader();
-
+    public void onFetchPage(@Nonnull Downloader downloader) throws IOException, ExtractionException {
         final String contentCountry = getContentCountry();
         String url = getCleanUrl();
         if(contentCountry != null && !contentCountry.isEmpty()) {
diff --git a/src/main/java/org/schabi/newpipe/extractor/stream/StreamInfo.java b/src/main/java/org/schabi/newpipe/extractor/stream/StreamInfo.java
index 871720cc5..be0da42b5 100644
--- a/src/main/java/org/schabi/newpipe/extractor/stream/StreamInfo.java
+++ b/src/main/java/org/schabi/newpipe/extractor/stream/StreamInfo.java
@@ -236,7 +236,8 @@ public class StreamInfo extends Info {
      * Fills out the video info fields which are common to all services.
      * Probably needs to be overridden by subclasses
      */
-    public static StreamInfo getInfo(StreamExtractor extractor) throws ExtractionException {
+    private static StreamInfo getInfo(StreamExtractor extractor) throws ExtractionException, IOException {
+        extractor.fetchPage();
         StreamInfo streamInfo;
         try {
             streamInfo = extractImportantData(extractor);
diff --git a/src/main/java/org/schabi/newpipe/extractor/stream/SubtitlesFormat.java b/src/main/java/org/schabi/newpipe/extractor/stream/SubtitlesFormat.java
index a45454800..3a16f1059 100644
--- a/src/main/java/org/schabi/newpipe/extractor/stream/SubtitlesFormat.java
+++ b/src/main/java/org/schabi/newpipe/extractor/stream/SubtitlesFormat.java
@@ -1,7 +1,5 @@
 package org.schabi.newpipe.extractor.stream;
 
-import org.schabi.newpipe.extractor.Subtitles;
-
 public enum SubtitlesFormat {
     // YouTube subtitles formats
     // TRANSCRIPT(3) is default YT format based on TTML,
@@ -13,8 +11,8 @@ public enum SubtitlesFormat {
     TRANSCRIPT2 (0x3, "srv2"),
     TRANSCRIPT3 (0x4, "srv3");
 
-    private int id;
-    private String extension;
+    private final int id;
+    private final String extension;
 
     SubtitlesFormat(int id, String extension) {
         this.id = id;
diff --git a/src/main/java/org/schabi/newpipe/extractor/stream/VideoStream.java b/src/main/java/org/schabi/newpipe/extractor/stream/VideoStream.java
index 76fa20c1a..1e877bee3 100644
--- a/src/main/java/org/schabi/newpipe/extractor/stream/VideoStream.java
+++ b/src/main/java/org/schabi/newpipe/extractor/stream/VideoStream.java
@@ -23,8 +23,8 @@ package org.schabi.newpipe.extractor.stream;
 import org.schabi.newpipe.extractor.MediaFormat;
 
 public class VideoStream extends Stream {
-    public String resolution;
-    public boolean isVideoOnly;
+    public final String resolution;
+    public final boolean isVideoOnly;
 
 
     public VideoStream(String url, MediaFormat format, String resolution) {
diff --git a/src/test/java/org/schabi/newpipe/Downloader.java b/src/test/java/org/schabi/newpipe/Downloader.java
index 542c853bf..e3bb6f68c 100644
--- a/src/test/java/org/schabi/newpipe/Downloader.java
+++ b/src/test/java/org/schabi/newpipe/Downloader.java
@@ -9,7 +9,6 @@ import java.io.InputStreamReader;
 import java.net.URL;
 import java.net.UnknownHostException;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.Map;
 
 
diff --git a/src/test/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractorDefaultTest.java b/src/test/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractorDefaultTest.java
index 52af87eb1..b05dfc127 100644
--- a/src/test/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractorDefaultTest.java
+++ b/src/test/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudStreamExtractorDefaultTest.java
@@ -29,6 +29,7 @@ public class SoundcloudStreamExtractorDefaultTest {
     public void setUp() throws Exception {
         NewPipe.init(Downloader.getInstance());
         extractor = (SoundcloudStreamExtractor) SoundCloud.getService().getStreamExtractor("https://soundcloud.com/liluzivert/do-what-i-want-produced-by-maaly-raw-don-cannon");
+        extractor.fetchPage();
     }
 
     @Test
diff --git a/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorDefaultTest.java b/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorDefaultTest.java
index 789d60206..92a63ab13 100644
--- a/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorDefaultTest.java
+++ b/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorDefaultTest.java
@@ -41,12 +41,14 @@ import static org.schabi.newpipe.extractor.ServiceList.YouTube;
  */
 public class YoutubeStreamExtractorDefaultTest {
     public static final String HTTPS = "https://";
-    private StreamExtractor extractor;
+    private YoutubeStreamExtractor extractor;
 
     @Before
     public void setUp() throws Exception {
         NewPipe.init(Downloader.getInstance());
-        extractor = YouTube.getService().getStreamExtractor("https://www.youtube.com/watch?v=rYEDA3JcQqw");
+        extractor = (YoutubeStreamExtractor) YouTube.getService()
+                .getStreamExtractor("https://www.youtube.com/watch?v=rYEDA3JcQqw");
+        extractor.fetchPage();
     }
 
     @Test
diff --git a/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorRestrictedTest.java b/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorRestrictedTest.java
index d1f209d53..32220aabc 100644
--- a/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorRestrictedTest.java
+++ b/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeStreamExtractorRestrictedTest.java
@@ -28,6 +28,7 @@ public class YoutubeStreamExtractorRestrictedTest {
         NewPipe.init(Downloader.getInstance());
         extractor = (YoutubeStreamExtractor) YouTube.getService()
                 .getStreamExtractor("https://www.youtube.com/watch?v=i6JTvzrpBy0");
+        extractor.fetchPage();
     }
 
     @Test
diff --git a/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractorTest.java b/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractorTest.java
index 9deea4919..0df208a0a 100644
--- a/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractorTest.java
+++ b/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeTrendingExtractorTest.java
@@ -70,7 +70,7 @@ public class YoutubeTrendingExtractorTest {
     public void testGetStreams() throws Exception {
         StreamInfoItemCollector collector = extractor.getStreams();
         Utils.printErrors(collector);
-        assertTrue("no streams are received", collector.getItemList().isEmpty());
+        assertFalse("no streams are received", collector.getItemList().isEmpty());
     }
 
     @Test