diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/exceptions/ReCaptchaException.java b/extractor/src/main/java/org/schabi/newpipe/extractor/exceptions/ReCaptchaException.java
index 504ea8fe0..b077ae598 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/exceptions/ReCaptchaException.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/exceptions/ReCaptchaException.java
@@ -21,7 +21,7 @@ package org.schabi.newpipe.extractor.exceptions;
  */
 
 public class ReCaptchaException extends ExtractionException {
-    private String url;
+    private final String url;
 
     public ReCaptchaException(final String message, final String url) {
         super(message);
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/media_ccc/extractors/MediaCCCLiveStreamKiosk.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/media_ccc/extractors/MediaCCCLiveStreamKiosk.java
index 14049bb3c..260b04f36 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/media_ccc/extractors/MediaCCCLiveStreamKiosk.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/media_ccc/extractors/MediaCCCLiveStreamKiosk.java
@@ -16,7 +16,7 @@ import javax.annotation.Nonnull;
 import java.io.IOException;
 
 public class MediaCCCLiveStreamKiosk extends KioskExtractor<StreamInfoItem> {
-    public JsonArray doc;
+    private JsonArray doc;
 
     public MediaCCCLiveStreamKiosk(StreamingService streamingService, ListLinkHandler linkHandler, String kioskId) {
         super(streamingService, linkHandler, kioskId);
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java
index 1aac227a5..2c3778468 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java
@@ -46,7 +46,7 @@ public class SoundcloudParsingHelper {
     private SoundcloudParsingHelper() {
     }
 
-    public synchronized static String clientId() throws ExtractionException, IOException {
+    public static synchronized String clientId() throws ExtractionException, IOException {
         if (!isNullOrEmpty(clientId)) return clientId;
 
         Downloader dl = NewPipe.getDownloader();
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChannelLinkHandlerFactory.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChannelLinkHandlerFactory.java
index 4ef513b87..e49834ebc 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChannelLinkHandlerFactory.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChannelLinkHandlerFactory.java
@@ -10,7 +10,7 @@ import java.util.List;
 
 public class SoundcloudChannelLinkHandlerFactory extends ListLinkHandlerFactory {
     private static final SoundcloudChannelLinkHandlerFactory instance = new SoundcloudChannelLinkHandlerFactory();
-    private final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/[0-9a-z_-]+" +
+    private static final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/[0-9a-z_-]+" +
             "(/((tracks|albums|sets|reposts|followers|following)/?)?)?([#?].*)?$";
 
     public static SoundcloudChannelLinkHandlerFactory getInstance() {
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChartsLinkHandlerFactory.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChartsLinkHandlerFactory.java
index 546564e4b..dfe1c80a0 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChartsLinkHandlerFactory.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudChartsLinkHandlerFactory.java
@@ -6,8 +6,8 @@ import org.schabi.newpipe.extractor.utils.Parser;
 import java.util.List;
 
 public class SoundcloudChartsLinkHandlerFactory extends ListLinkHandlerFactory {
-    private final String TOP_URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/charts(/top)?/?([#?].*)?$";
-    private final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/charts(/top|/new)?/?([#?].*)?$";
+    private static final String TOP_URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/charts(/top)?/?([#?].*)?$";
+    private static final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/charts(/top|/new)?/?([#?].*)?$";
 
 
     @Override
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudPlaylistLinkHandlerFactory.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudPlaylistLinkHandlerFactory.java
index 53a70d3aa..3adade10c 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudPlaylistLinkHandlerFactory.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudPlaylistLinkHandlerFactory.java
@@ -10,7 +10,7 @@ import java.util.List;
 
 public class SoundcloudPlaylistLinkHandlerFactory extends ListLinkHandlerFactory {
     private static final SoundcloudPlaylistLinkHandlerFactory instance = new SoundcloudPlaylistLinkHandlerFactory();
-    private final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/[0-9a-z_-]+" +
+    private static final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/[0-9a-z_-]+" +
             "/sets/[0-9a-z_-]+/?([#?].*)?$";
 
     public static SoundcloudPlaylistLinkHandlerFactory getInstance() {
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudStreamLinkHandlerFactory.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudStreamLinkHandlerFactory.java
index e271345d5..48aa836e1 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudStreamLinkHandlerFactory.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/linkHandler/SoundcloudStreamLinkHandlerFactory.java
@@ -8,7 +8,7 @@ import org.schabi.newpipe.extractor.utils.Utils;
 
 public class SoundcloudStreamLinkHandlerFactory extends LinkHandlerFactory {
     private static final SoundcloudStreamLinkHandlerFactory instance = new SoundcloudStreamLinkHandlerFactory();
-    private final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/[0-9a-z_-]+" +
+    private static final String URL_PATTERN = "^https?://(www\\.|m\\.)?soundcloud.com/[0-9a-z_-]+" +
             "/(?!(tracks|albums|sets|reposts|followers|following)/?$)[0-9a-z_-]+/?([#?].*)?$";
 
     private SoundcloudStreamLinkHandlerFactory() {