diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/source/online/english/Batoto.java b/app/src/main/java/eu/kanade/tachiyomi/data/source/online/english/Batoto.java
index ae094dacfb..bf7ac21a36 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/source/online/english/Batoto.java
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/source/online/english/Batoto.java
@@ -106,21 +106,21 @@ public class Batoto extends LoginSource {
 
     @Override
     protected Request mangaDetailsRequest(String mangaUrl) {
-        String mangaId = mangaUrl.substring(mangaUrl.lastIndexOf("r") + 1);
+        String mangaId = mangaUrl.substring(mangaUrl.lastIndexOf('r') + 1);
         return ReqKt.get(String.format(MANGA_URL, mangaId), getRequestHeaders());
     }
 
     @Override
     protected Request pageListRequest(String pageUrl) {
-        String id = pageUrl.substring(pageUrl.indexOf("#") + 1);
+        String id = pageUrl.substring(pageUrl.indexOf('#') + 1);
         return ReqKt.get(String.format(CHAPTER_URL, id), getRequestHeaders());
     }
 
     @Override
     protected Request imageUrlRequest(Page page) {
         String pageUrl = page.getUrl();
-        int start = pageUrl.indexOf("#") + 1;
-        int end = pageUrl.indexOf("_", start);
+        int start = pageUrl.indexOf('#') + 1;
+        int end = pageUrl.indexOf('_', start);
         String id = pageUrl.substring(start, end);
         return ReqKt.get(String.format(PAGE_URL, id, pageUrl.substring(end+1)), getRequestHeaders());
     }
diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/source/online/russian/Mangachan.java b/app/src/main/java/eu/kanade/tachiyomi/data/source/online/russian/Mangachan.java
index 015d90361e..4fa8c8c96c 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/source/online/russian/Mangachan.java
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/source/online/russian/Mangachan.java
@@ -204,7 +204,7 @@ public class Mangachan extends Source {
         ArrayList<String> pages = new ArrayList<>();
 
         int beginIndex = unparsedHtml.indexOf("fullimg\":[");
-        int endIndex = unparsedHtml.indexOf("]", beginIndex);
+        int endIndex = unparsedHtml.indexOf(']', beginIndex);
 
         String trimmedHtml = unparsedHtml.substring(beginIndex + 10, endIndex);
         trimmedHtml = trimmedHtml.replaceAll("\"", "");
@@ -220,7 +220,7 @@ public class Mangachan extends Source {
     @Override
     protected List<Page> parseFirstPage(List<? extends Page> pages, String unparsedHtml) {
         int beginIndex = unparsedHtml.indexOf("fullimg\":[");
-        int endIndex = unparsedHtml.indexOf("]", beginIndex);
+        int endIndex = unparsedHtml.indexOf(']', beginIndex);
 
         String trimmedHtml = unparsedHtml.substring(beginIndex + 10, endIndex);
         trimmedHtml = trimmedHtml.replaceAll("\"", "");