Use Collectors.joining().

app/src/main/java/org/schabi/newpipe/DownloaderImpl.java

@@ -11,15 +11,17 @@ import org.schabi.newpipe.extractor.downloader.Downloader;
 import org.schabi.newpipe.extractor.downloader.Request;
 import org.schabi.newpipe.extractor.downloader.Response;
 import org.schabi.newpipe.extractor.exceptions.ReCaptchaException;
-import org.schabi.newpipe.util.CookieUtils;
 import org.schabi.newpipe.util.InfoCache;
 
 import java.io.IOException;
-import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import okhttp3.OkHttpClient;
 import okhttp3.RequestBody;
@@ -63,19 +65,15 @@ public final class DownloaderImpl extends Downloader {
     }
 
     public String getCookies(final String url) {
-        final List<String> resultCookies = new ArrayList<>();
+        final String youtubeCookie = url.contains(YOUTUBE_DOMAIN)
-        if (url.contains(YOUTUBE_DOMAIN)) {
+                ? getCookie(YOUTUBE_RESTRICTED_MODE_COOKIE_KEY) : null;
-            final String youtubeCookie = getCookie(YOUTUBE_RESTRICTED_MODE_COOKIE_KEY);
+
-            if (youtubeCookie != null) {
-                resultCookies.add(youtubeCookie);
-            }
-        }
         // Recaptcha cookie is always added TODO: not sure if this is necessary
-        final String recaptchaCookie = getCookie(ReCaptchaActivity.RECAPTCHA_COOKIES_KEY);
+        return Stream.of(youtubeCookie, getCookie(ReCaptchaActivity.RECAPTCHA_COOKIES_KEY))
-        if (recaptchaCookie != null) {
+                .filter(Objects::nonNull)
-            resultCookies.add(recaptchaCookie);
+                .flatMap(cookies -> Arrays.stream(cookies.split("; *")))
-        }
+                .distinct()
-        return CookieUtils.concatCookies(resultCookies);
+                .collect(Collectors.joining("; "));
     }
 
     public String getCookie(final String key) {

app/src/main/java/org/schabi/newpipe/error/ErrorActivity.java

@@ -31,6 +31,7 @@ import org.schabi.newpipe.util.external_communication.ShareUtils;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
 import java.util.Arrays;
+import java.util.stream.Collectors;
 
 /*
  * Created by Christian Schabesberger on 24.10.15.
@@ -182,14 +183,9 @@ public class ErrorActivity extends AppCompatActivity {
     }
 
     private String formErrorText(final String[] el) {
-        final StringBuilder text = new StringBuilder();
+        final String separator = "-------------------------------------";
-        if (el != null) {
+        return Arrays.stream(el)
-            for (final String e : el) {
+                .collect(Collectors.joining(separator + "\n", separator + "\n", separator));
-                text.append("-------------------------------------\n").append(e);
-            }
-        }
-        text.append("-------------------------------------");
-        return text.toString();
     }
 
     /**

app/src/main/java/org/schabi/newpipe/settings/preferencesearch/PreferenceParser.java

@@ -9,13 +9,13 @@ import androidx.annotation.Nullable;
 import androidx.annotation.XmlRes;
 import androidx.preference.PreferenceManager;
 
+import org.schabi.newpipe.util.Localization;
 import org.xmlpull.v1.XmlPullParser;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 
 /**
  * Parses the corresponding preference-file(s).
@@ -54,7 +54,7 @@ public class PreferenceParser {
                 if (xpp.getEventType() == XmlPullParser.START_TAG) {
                     final PreferenceSearchItem result = parseSearchResult(
                             xpp,
-                            joinBreadcrumbs(breadcrumbs),
+                            Localization.concatenateStrings(" > ", breadcrumbs),
                             resId
                     );
 
@@ -82,12 +82,6 @@ public class PreferenceParser {
         return results;
     }
 
-    private String joinBreadcrumbs(final List<String> breadcrumbs) {
-        return breadcrumbs.stream()
-                .filter(crumb -> !TextUtils.isEmpty(crumb))
-                .collect(Collectors.joining(" > "));
-    }
-
     private String getAttribute(
             final XmlPullParser xpp,
             @NonNull final String attribute

app/src/main/java/org/schabi/newpipe/util/CookieUtils.java

@@ -1,24 +0,0 @@
-package org.schabi.newpipe.util;
-
-import android.text.TextUtils;
-
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Set;
-
-public final class CookieUtils {
-    private CookieUtils() {
-    }
-
-    public static String concatCookies(final Collection<String> cookieStrings) {
-        final Set<String> cookieSet = new HashSet<>();
-        for (final String cookies : cookieStrings) {
-            cookieSet.addAll(splitCookies(cookies));
-        }
-        return TextUtils.join("; ", cookieSet).trim();
-    }
-
-    public static Set<String> splitCookies(final String cookies) {
-        return Set.of(cookies.split("; *"));
-    }
-}

app/src/main/java/org/schabi/newpipe/util/Localization.java

@@ -32,6 +32,7 @@ import java.time.format.FormatStyle;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
+import java.util.stream.Collectors;
 
 
 /*
@@ -63,26 +64,14 @@ public final class Localization {
 
     @NonNull
     public static String concatenateStrings(final String... strings) {
-        return concatenateStrings(Arrays.asList(strings));
+        return concatenateStrings(DOT_SEPARATOR, Arrays.asList(strings));
     }
 
     @NonNull
-    public static String concatenateStrings(final List<String> strings) {
+    public static String concatenateStrings(final String delimiter, final List<String> strings) {
-        if (strings.isEmpty()) {
+        return strings.stream()
-            return "";
+                .filter(string -> !TextUtils.isEmpty(string))
-        }
+                .collect(Collectors.joining(delimiter));
-
-        final StringBuilder stringBuilder = new StringBuilder();
-        stringBuilder.append(strings.get(0));
-
-        for (int i = 1; i < strings.size(); i++) {
-            final String string = strings.get(i);
-            if (!TextUtils.isEmpty(string)) {
-                stringBuilder.append(DOT_SEPARATOR).append(strings.get(i));
-            }
-        }
-
-        return stringBuilder.toString();
     }
 
     public static org.schabi.newpipe.extractor.localization.Localization getPreferredLocalization(