diff --git a/core-java-modules/core-java-string-operations-7/README.md b/core-java-modules/core-java-string-operations-7/README.md
index 97249b1a8b..0ef528f162 100644
--- a/core-java-modules/core-java-string-operations-7/README.md
+++ b/core-java-modules/core-java-string-operations-7/README.md
@@ -6,7 +6,6 @@
 - [Check if a String Contains a Number Value in Java](https://www.baeldung.com/java-string-number-presence)
 - [String’s Maximum Length in Java](https://www.baeldung.com/java-strings-maximum-length)
 - [Java’s String.length() and String.getBytes().length](https://www.baeldung.com/java-string-length-vs-getbytes-length)
-- [Check If a Java StringBuilder Object Contains a Character](https://www.baeldung.com/java-check-stringbuilder-object-contains-character)
 - [Comparing One String With Multiple Values in One Expression in Java](https://www.baeldung.com/java-compare-string-multiple-values-one-expression)
 - [Regular Expression for Password Validation in Java](https://www.baeldung.com/java-regex-password-validation)
 - [Mask an Email Address and Phone Number in Java](https://www.baeldung.com/java-mask-email-address-phone-number)
diff --git a/core-java-modules/core-java-string-operations-9/README.md b/core-java-modules/core-java-string-operations-9/README.md
index aab4178988..a7e3f6de58 100644
--- a/core-java-modules/core-java-string-operations-9/README.md
+++ b/core-java-modules/core-java-string-operations-9/README.md
@@ -6,4 +6,5 @@
 - [UTF-8 Validation in Java](https://www.baeldung.com/java-utf-8-validation)
 - [Simple Morse Code Translation in Java](https://www.baeldung.com/java-morse-code-english-translate)
 - [How to Determine if a String Contains Invalid Encoded Characters](https://www.baeldung.com/java-check-string-contains-invalid-encoded-characters)
+- [Check If a Java StringBuilder Object Contains a Character](https://www.baeldung.com/java-check-stringbuilder-object-contains-character)
 - More articles: [[<-- prev]](../core-java-string-operations-8)
diff --git a/core-java-modules/core-java-string-operations-7/src/test/java/com/baeldung/stringbuilderhaschar/CheckIfStringBuilderContainsCharUnitTest.java b/core-java-modules/core-java-string-operations-9/src/test/java/com/baeldung/stringbuilderhaschar/CheckIfStringBuilderContainsCharUnitTest.java
similarity index 92%
rename from core-java-modules/core-java-string-operations-7/src/test/java/com/baeldung/stringbuilderhaschar/CheckIfStringBuilderContainsCharUnitTest.java
rename to core-java-modules/core-java-string-operations-9/src/test/java/com/baeldung/stringbuilderhaschar/CheckIfStringBuilderContainsCharUnitTest.java
index 8d95b5533a..31740152e5 100644
--- a/core-java-modules/core-java-string-operations-7/src/test/java/com/baeldung/stringbuilderhaschar/CheckIfStringBuilderContainsCharUnitTest.java
+++ b/core-java-modules/core-java-string-operations-9/src/test/java/com/baeldung/stringbuilderhaschar/CheckIfStringBuilderContainsCharUnitTest.java
@@ -2,7 +2,7 @@ package com.baeldung.stringbuilderhaschar;
 
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class CheckIfStringBuilderContainsCharUnitTest {