diff --git a/.idea/checkstyle-idea.xml b/.idea/checkstyle-idea.xml
index b767a3113c..87234f98cb 100644
--- a/.idea/checkstyle-idea.xml
+++ b/.idea/checkstyle-idea.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="CheckStyle-IDEA" serialisationVersion="2">
-    <checkstyleVersion>10.14.2</checkstyleVersion>
+    <checkstyleVersion>10.23.0</checkstyleVersion>
     <scanScope>JavaOnly</scanScope>
     <copyLibs>true</copyLibs>
     <option name="thirdPartyClasspath" />
diff --git a/.idea/compiler.xml b/.idea/compiler.xml
index ebcb13b8aa..7d6d2ebcd2 100644
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@@ -12,7 +12,6 @@
         <module name="lucene" />
         <module name="core-java-annotations" />
         <module name="core-java-uuid" />
-        <module name="core-java-numbers" />
         <module name="jackson-polymorphic-deserialization" />
         <module name="ethereum" />
         <module name="core-java-strings" />
@@ -24,48 +23,35 @@
         <module name="core-java-datetime-conversion" />
         <module name="core-java-lambdas" />
         <module name="junit-5-basics" />
-        <module name="spring-data-jpa-repo" />
         <module name="apache-velocity" />
         <module name="jackson-conversions-2" />
         <module name="activejdbc" />
-        <module name="codebank" />
         <module name="core-java-collections-list" />
-        <module name="spring-data-jpa-repo-2" />
         <module name="image-compressing" />
         <module name="core-java-streams" />
         <module name="core-java-io-2" />
         <module name="core-java-io" />
         <module name="core-java-8-datetime" />
-        <module name="discourse" />
         <module name="image-processing" />
         <module name="jackson-jr" />
         <module name="spring-data-redis" />
         <module name="xml-2" />
         <module name="core-java" />
         <module name="jackson-custom-conversions" />
-        <module name="core-java-collections-list-2" />
         <module name="core-java-collections-conversions-2" />
         <module name="jackson-exceptions" />
-        <module name="core-java-8" />
+        <module name="xstream" />
         <module name="apache-httpclient" />
+        <module name="core-java-8" />
         <module name="core-java-collections-3" />
         <module name="core-java-9" />
         <module name="jackson-conversions" />
         <module name="core-java-collections-2" />
       </profile>
     </annotationProcessing>
-    <bytecodeTargetLevel>
-      <module name="core-java-10" target="17" />
-      <module name="core-java-11-2" target="11" />
-      <module name="core-java-8-2" target="11" />
-      <module name="core-java-collections-list-3" target="11" />
-      <module name="jackson-annotations" target="17" />
-      <module name="spring-data-jpa-repo-2" target="17" />
-    </bytecodeTargetLevel>
   </component>
   <component name="JavacSettings">
     <option name="ADDITIONAL_OPTIONS_OVERRIDE">
-      <module name="core-java-9" options="" />
       <module name="core-java-streams" options="-parameters" />
     </option>
   </component>
diff --git a/.idea/dataSources.xml b/.idea/dataSources.xml
deleted file mode 100644
index b9687fac26..0000000000
--- a/.idea/dataSources.xml
+++ /dev/null
@@ -1,17 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="DataSourceManagerImpl" format="xml" multifile-model="true">
-    <data-source source="LOCAL" name="postgres@nas1120" uuid="33f98331-7e30-4939-9d10-a9d8ae4f65f2">
-      <driver-ref>postgresql</driver-ref>
-      <synchronize>true</synchronize>
-      <jdbc-driver>org.postgresql.Driver</jdbc-driver>
-      <jdbc-url>jdbc:postgresql://nas1120:5433/postgres</jdbc-url>
-      <jdbc-additional-properties>
-        <property name="com.intellij.clouds.kubernetes.db.host.port" />
-        <property name="com.intellij.clouds.kubernetes.db.enabled" value="false" />
-        <property name="com.intellij.clouds.kubernetes.db.container.port" />
-      </jdbc-additional-properties>
-      <working-dir>$ProjectFileDir$</working-dir>
-    </data-source>
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/encodings.xml b/.idea/encodings.xml
index 612addbb27..f8feab6f94 100644
--- a/.idea/encodings.xml
+++ b/.idea/encodings.xml
@@ -7,14 +7,8 @@
     <file url="file://$PROJECT_DIR$/apache/apache-velocity/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/apache/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/apache/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-10/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-10/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11-2/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11-2/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8-2/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8-2/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8-datetime/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8-datetime/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8/src/main/java" charset="UTF-8" />
@@ -31,10 +25,6 @@
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-conversions-2/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-conversions/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-conversions/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-2/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-2/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-3/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-3/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections/src/main/java" charset="UTF-8" />
@@ -47,8 +37,6 @@
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-io/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-lambdas/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-lambdas/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-numbers/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-numbers/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-serialization/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-serialization/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/core-java-modules/core-java-streams/src/main/java" charset="UTF-8" />
@@ -67,8 +55,6 @@
     <file url="file://$PROJECT_DIR$/image-compressing/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/image-processing/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/image-processing/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/libraries-jackson/jackson-annotations/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/libraries-jackson/jackson-annotations/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/libraries-jackson/jackson-conversions-2/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/libraries-jackson/jackson-conversions-2/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/libraries-jackson/jackson-conversions/src/main/java" charset="UTF-8" />
@@ -93,10 +79,6 @@
     <file url="file://$PROJECT_DIR$/parent-boot-3/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/persistence-modules/activejdbc/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/persistence-modules/activejdbc/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/persistence-modules/spring-data-jpa-repo-2/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/persistence-modules/spring-data-jpa-repo-2/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/persistence-modules/spring-data-jpa-repo/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/persistence-modules/spring-data-jpa-repo/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/persistence-modules/spring-data-redis/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/persistence-modules/spring-data-redis/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/persistence-modules/src/main/java" charset="UTF-8" />
@@ -110,13 +92,11 @@
     <file url="file://$PROJECT_DIR$/testing-modules/junit-5-basics/src/test/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/testing-modules/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/testing-modules/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/toolkits/codebank/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/toolkits/codebank/src/main/resources" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/toolkits/discourse/src/main/java" charset="UTF-8" />
-    <file url="file://$PROJECT_DIR$/toolkits/discourse/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/xml-2/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/xml-2/src/main/resources" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/xml/src/main/java" charset="UTF-8" />
     <file url="file://$PROJECT_DIR$/xml/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/xstream/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/xstream/src/main/resources" charset="UTF-8" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
deleted file mode 100644
index 9c69411050..0000000000
--- a/.idea/inspectionProfiles/Project_Default.xml
+++ /dev/null
@@ -1,7 +0,0 @@
-<component name="InspectionProjectProfileManager">
-  <profile version="1.0">
-    <option name="myName" value="Project Default" />
-    <inspection_tool class="Eslint" enabled="true" level="WARNING" enabled_by_default="true" />
-    <inspection_tool class="TsLint" enabled="true" level="WARNING" enabled_by_default="true" />
-  </profile>
-</component>
\ No newline at end of file
diff --git a/.idea/jarRepositories.xml b/.idea/jarRepositories.xml
index da3c1d5f51..54c93d6811 100644
--- a/.idea/jarRepositories.xml
+++ b/.idea/jarRepositories.xml
@@ -1,105 +1,30 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="RemoteRepositoriesConfiguration">
-    <remote-repository>
-      <option name="id" value="central" />
-      <option name="name" value="Central Repository" />
-      <option name="url" value="https://repo.maven.apache.org/maven2" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-snapshots" />
-      <option name="name" value="OSSEZ Private Snapshots" />
-      <option name="url" value="https://repo.ossez.com/repository/maven-snapshots/" />
-    </remote-repository>
     <remote-repository>
       <option name="id" value="ossez-repo-releases" />
       <option name="name" value="iSharkFly Private Releases" />
       <option name="url" value="https://repo.isharkfly.com/repository/isharkfly-maven-releases/" />
     </remote-repository>
-    <remote-repository>
-      <option name="id" value="central" />
-      <option name="name" value="Central Repository" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-releases" />
-      <option name="name" value="OSSEZ Private Releases" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="central" />
-      <option name="name" value="Central Repository" />
-      <option name="url" value="https://repo.ossez.com/repository/maven-public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-releases" />
-      <option name="name" value="iSharkFly Private Releases" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="central" />
-      <option name="name" value="Maven Central repository" />
-      <option name="url" value="https://repo1.maven.org/maven2" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-snapshots" />
-      <option name="name" value="OSSEZ Private Snapshots" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-snapshots" />
-      <option name="name" value="iSharkFly Private Snapshots" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-public/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-snapshots" />
-      <option name="name" value="iSharkFly Private Snapshots" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-snapshots/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="" />
-      <option name="name" value="" />
-      <option name="url" value="https://repo.maven.apache.org/maven2/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-snapshots" />
-      <option name="name" value="OSSEZ Private Snapshots" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-snapshots/" />
-    </remote-repository>
-    <remote-repository>
-      <option name="id" value="Ethereum" />
-      <option name="name" value="Ethereum" />
-      <option name="url" value="https://dl.bintray.com/ethereum/maven/" />
-    </remote-repository>
     <remote-repository>
       <option name="id" value="central" />
       <option name="name" value="Central Repository" />
       <option name="url" value="https://repo.isharkfly.com/repository/maven/" />
     </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-releases" />
-      <option name="name" value="OSSEZ Private Releases" />
-      <option name="url" value="https://repo.ossez.com/repository/maven-releases/" />
-    </remote-repository>
     <remote-repository>
       <option name="id" value="ossez-repo-snapshots" />
       <option name="name" value="iSharkFly Private Snapshots" />
       <option name="url" value="https://repo.isharkfly.com/repository/isharkfly-maven-snapshots/" />
     </remote-repository>
     <remote-repository>
-      <option name="id" value="ossez-repo-releases" />
-      <option name="name" value="iSharkFly Private Releases" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-releases/" />
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
     </remote-repository>
     <remote-repository>
       <option name="id" value="jboss.community" />
       <option name="name" value="JBoss Community repository" />
       <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
     </remote-repository>
-    <remote-repository>
-      <option name="id" value="ossez-repo-releases" />
-      <option name="name" value="OSSEZ Private Releases" />
-      <option name="url" value="https://repo.isharkfly.com/repository/maven-releases/" />
-    </remote-repository>
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/jpa.xml b/.idea/jpa.xml
deleted file mode 100644
index 898e07a675..0000000000
--- a/.idea/jpa.xml
+++ /dev/null
@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="JpaBuddyIdeaProjectConfig">
-    <option name="defaultUnitInitialized" value="true" />
-    <option name="renamerInitialized" value="true" />
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/prettier.xml b/.idea/prettier.xml
deleted file mode 100644
index b0c1c68fbb..0000000000
--- a/.idea/prettier.xml
+++ /dev/null
@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="PrettierConfiguration">
-    <option name="myConfigurationMode" value="AUTOMATIC" />
-  </component>
-</project>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index d721685dae..e2d58f5205 100644
--- a/pom.xml
+++ b/pom.xml
@@ -56,6 +56,7 @@
         <module>toolkits</module>
         <module>xml</module>
         <module>xml-2</module>
+        <module>xstream</module>
     </modules>
 
     <properties>
diff --git a/xstream/pom.xml b/xstream/pom.xml
index 6f25e67e12..8f14d1c833 100644
--- a/xstream/pom.xml
+++ b/xstream/pom.xml
@@ -10,9 +10,9 @@
     <description>An Introduction To XStream</description>
 
     <parent>
-        <groupId>com.baeldung</groupId>
+        <groupId>com.ossez</groupId>
         <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
+        <version>0.0.2-SNAPSHOT</version>
     </parent>
 
     <dependencies>
diff --git a/xstream/src/test/java/com/baeldung/rce/AppUnitTest.java b/xstream/src/test/java/com/baeldung/rce/AppUnitTest.java
index 3b541ae099..19d9b60463 100644
--- a/xstream/src/test/java/com/baeldung/rce/AppUnitTest.java
+++ b/xstream/src/test/java/com/baeldung/rce/AppUnitTest.java
@@ -9,6 +9,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.SocketException;
+import java.net.URI;
 import java.net.URL;
 
 import static org.junit.Assert.assertTrue;
@@ -43,9 +44,9 @@ public final class AppUnitTest {
      * side-effect that is difficult to observe.
      */
     @Test(expected = SocketException.class)
-    public void givenAppIsVulneable_whenExecuteRemoteCodeWhichThrowsException_thenThrowsException() throws IOException {
+    public void givenAppIsVulneable_whenExecuteRemoteCodeWhichThrowsException_thenThrowsException() throws Exception {
         // POST the attack.xml to the application's /persons endpoint
-        final URL url = new URL("http://localhost:" + app.port() + "/persons");
+        final URL url = new URI("http://localhost:" + app.port() + "/persons").toURL();
         final HttpURLConnection connection = (HttpURLConnection) url.openConnection();
         connection.setRequestMethod("POST");
         connection.setDoOutput(true);