Add final and adjust utils class name

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeThrottlingDecrypter.java

@@ -3,7 +3,7 @@ package org.schabi.newpipe.extractor.services.youtube;
 import org.schabi.newpipe.extractor.exceptions.ParsingException;
 import org.schabi.newpipe.extractor.utils.JavaScript;
 import org.schabi.newpipe.extractor.utils.Parser;
-import org.schabi.newpipe.extractor.utils.StringUtil;
+import org.schabi.newpipe.extractor.utils.StringUtils;
 
 import javax.annotation.Nonnull;
 import java.util.HashMap;
@@ -81,7 +81,7 @@ public class YoutubeThrottlingDecrypter {
 
     private String parseWithParenthesisMatching(final String playerJsCode, final String functionName) {
         final String functionBase = functionName + "=function";
-        return functionBase + StringUtil.matchToClosingParenthesis(playerJsCode, functionBase) + ";";
+        return functionBase + StringUtils.matchToClosingParenthesis(playerJsCode, functionBase) + ";";
     }
 
     private String parseWithRegex(final String playerJsCode, final String functionName) throws Parser.RegexException {

extractor/src/main/java/org/schabi/newpipe/extractor/utils/Parser.java

@@ -79,13 +79,13 @@ public class Parser {
     }
 
     public static boolean isMatch(String pattern, String input) {
-        Pattern pat = Pattern.compile(pattern);
+        final Pattern pat = Pattern.compile(pattern);
-        Matcher mat = pat.matcher(input);
+        final Matcher mat = pat.matcher(input);
         return mat.find();
     }
 
     public static boolean isMatch(Pattern pattern, String input) {
-        Matcher mat = pattern.matcher(input);
+        final Matcher mat = pattern.matcher(input);
         return mat.find();
     }
 

extractor/src/main/java/org/schabi/newpipe/extractor/utils/StringUtils.java

@@ -1,20 +1,21 @@
 package org.schabi.newpipe.extractor.utils;
 
-import edu.umd.cs.findbugs.annotations.NonNull;
 
-public class StringUtil {
+import javax.annotation.Nonnull;
 
-    private StringUtil() {
+public class StringUtils {
+
+    private StringUtils() {
     }
 
     /**
      * @param string The string to search in
      * @param start A string from which to start searching.
      * @return A substring where each '{' matches a '}'
-     * @throws IndexOutOfBoundsException If {@ string} does not contain {@code start}
+     * @throws IndexOutOfBoundsException If {@code string} does not contain {@code start}
      */
-    @NonNull
+    @Nonnull
-    public static String matchToClosingParenthesis(@NonNull final String string, @NonNull final String start) {
+    public static String matchToClosingParenthesis(@Nonnull final String string, @Nonnull final String start) {
         int startIndex = string.indexOf(start);
         if (startIndex < 0) {
             throw new IndexOutOfBoundsException();

extractor/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubeThrottlingDecrypterTest.java

@@ -23,11 +23,11 @@ public class YoutubeThrottlingDecrypterTest {
 
     @Test
     public void testExtractFunction__success() throws ParsingException {
-        String[] videoIds = {"jE1USQrs1rw", "CqxjzfudGAc", "goH-9MfQI7w", "KYIdr_7H5Yw", "J1WeqmGbYeI"};
+        final String[] videoIds = {"jE1USQrs1rw", "CqxjzfudGAc", "goH-9MfQI7w", "KYIdr_7H5Yw", "J1WeqmGbYeI"};
 
         final String encryptedUrl = "https://r6---sn-4g5ednek.googlevideo.com/videoplayback?expire=1626562120&ei=6AnzYO_YBpql1gLGkb_IBQ&ip=127.0.0.1&id=o-ANhBEf36Z5h-8U9DDddtPDqtS0ZNwf0XJAAigudKI2uI&itag=278&aitags=133%2C134%2C135%2C136%2C137%2C160%2C242%2C243%2C244%2C247%2C248%2C278&source=youtube&requiressl=yes&vprv=1&mime=video%2Fwebm&ns=TvecOReN0vPuXb3j_zq157IG&gir=yes&clen=2915100&dur=270.203&lmt=1608157174907785&keepalive=yes&fexp=24001373,24007246&c=WEB&txp=5535432&n=N9BWSTFT7vvBJrvQ&sparams=expire%2Cei%2Cip%2Cid%2Caitags%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cns%2Cgir%2Cclen%2Cdur%2Clmt&alr=yes&sig=AOq0QJ8wRQIgW6XnUDKPDSxiT0_KE_tDDMpcaCJl2Un5p0Fu9qZNQGkCIQDWxsDHi_s2BEmRqIbd1C5g_gzfihB7RZLsScKWNMwzzA%3D%3D&cpn=9r2yt3BqcYmeb2Yu&cver=2.20210716.00.00&redirect_counter=1&cm2rm=sn-4g5ezy7s&cms_redirect=yes&mh=Y5&mm=34&mn=sn-4g5ednek&ms=ltu&mt=1626540524&mv=m&mvi=6&pl=43&lsparams=mh,mm,mn,ms,mv,mvi,pl&lsig=AG3C_xAwRQIhAIUzxTn9Vw1-vm-_7OQ5-0h1M6AZsY9Bx1FlCCTeMICzAiADtGggbn4Znsrh2EnvyOsGnYdRGcbxn4mW9JMOQiInDQ%3D%3D&range=259165-480735&rn=11&rbuf=20190";
 
-        for (String videoId : videoIds) {
+        for (final String videoId : videoIds) {
             try {
                 final String decryptedUrl = new YoutubeThrottlingDecrypter(videoId).apply(encryptedUrl);
                 assertNotEquals(encryptedUrl, decryptedUrl);