diff --git a/.idea/.name b/.idea/.name
deleted file mode 100644
index cb2497b5cb..0000000000
--- a/.idea/.name
+++ /dev/null
@@ -1 +0,0 @@
-cwiki-us-demo-tutorials
\ No newline at end of file
diff --git a/.idea/compiler.xml b/.idea/compiler.xml
index 180534cff0..c1f674d39e 100644
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@@ -7,18 +7,12 @@
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-        <module name="cwiki-us-demo-tutorials" />
         <module name="discourse" />
       </profile>
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-    <bytecodeTargetLevel target="1.8">
+    <bytecodeTargetLevel>
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-      <module name="cwiki-us-demo-tutorials" target="11" />
-      <module name="cwiki-us-demo-tutorials.spring-batch" target="11" />
-      <module name="cwiki-us-demo-tutorials.spring-batch.main" target="11" />
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diff --git a/.idea/jarRepositories.xml b/.idea/jarRepositories.xml
index 24dce4c262..712ab9d985 100644
--- a/.idea/jarRepositories.xml
+++ b/.idea/jarRepositories.xml
@@ -1,21 +1,11 @@
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 <project version="4">
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@@ -26,10 +16,5 @@
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   </component>
 </project>
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diff --git a/.idea/libraries-with-intellij-classes.xml b/.idea/libraries-with-intellij-classes.xml
deleted file mode 100644
index 9fa31567f1..0000000000
--- a/.idea/libraries-with-intellij-classes.xml
+++ /dev/null
@@ -1,65 +0,0 @@
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diff --git a/.idea/misc.xml b/.idea/misc.xml
index 740639b35c..17e19eb41d 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -6,11 +6,6 @@
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   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="11" project-jdk-type="JavaSDK" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="11" project-jdk-type="JavaSDK" />
 </project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
index 2da9b0836e..d29913b7c7 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -3,12 +3,6 @@
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diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 8996c0a2c9..58252cbbc8 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -4,291 +4,51 @@
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+      <changelist id="e4ccec40-1722-49be-ba56-1cba428e2e66" name="Default Changelist" comment="" />
+      <created>1619410137650</created>
       <option name="number" value="Default" />
       <option name="presentableId" value="Default" />
-      <updated>1618145802441</updated>
-      <workItem from="1618145805266" duration="1634000" />
-      <workItem from="1618147512704" duration="6933000" />
-      <workItem from="1618246818887" duration="17236000" />
-      <workItem from="1618429441584" duration="12732000" />
-      <workItem from="1619409043090" duration="688000" />
+      <updated>1619410137650</updated>
+      <workItem from="1619410141685" duration="105000" />
     </task>
-    <task id="LOCAL-00001" summary="更新 POM 文件">
-      <created>1618147556538</created>
-      <option name="number" value="00001" />
-      <option name="presentableId" value="LOCAL-00001" />
-      <option name="project" value="LOCAL" />
-      <updated>1618147556538</updated>
-    </task>
-    <task id="LOCAL-00002" summary="Discourse Topic import">
-      <created>1618147882644</created>
-      <option name="number" value="00002" />
-      <option name="presentableId" value="LOCAL-00002" />
-      <option name="project" value="LOCAL" />
-      <updated>1618147882644</updated>
-    </task>
-    <task id="LOCAL-00003" summary="项目的 POM 配置文件&#10;# Conflicts:&#10;#&#9;pom.xml">
-      <created>1618151038853</created>
-      <option name="number" value="00003" />
-      <option name="presentableId" value="LOCAL-00003" />
-      <option name="project" value="LOCAL" />
-      <updated>1618151038853</updated>
-    </task>
-    <task id="LOCAL-00004" summary="Discourse">
-      <created>1618157753954</created>
-      <option name="number" value="00004" />
-      <option name="presentableId" value="LOCAL-00004" />
-      <option name="project" value="LOCAL" />
-      <updated>1618157753954</updated>
-    </task>
-    <task id="LOCAL-00005" summary="添加忽略文件的内容">
-      <created>1618499169408</created>
-      <option name="number" value="00005" />
-      <option name="presentableId" value="LOCAL-00005" />
-      <option name="project" value="LOCAL" />
-      <updated>1618499169408</updated>
-    </task>
-    <task id="LOCAL-00006" summary="完成所有的文件的提交，以便于下一步的代码演示和开发">
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-      <option name="presentableId" value="LOCAL-00006" />
-      <option name="project" value="LOCAL" />
-      <updated>1618499203125</updated>
-    </task>
-    <task id="LOCAL-00007" summary="adjust the pom to make project can be compile">
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-      <option name="presentableId" value="LOCAL-00007" />
-      <option name="project" value="LOCAL" />
-      <updated>1618503350719</updated>
-    </task>
-    <task id="LOCAL-00008" summary="DiscourseImportTest move to different project">
-      <created>1618503445699</created>
-      <option name="number" value="00008" />
-      <option name="presentableId" value="LOCAL-00008" />
-      <option name="project" value="LOCAL" />
-      <updated>1618503445699</updated>
-    </task>
-    <task id="LOCAL-00009" summary="Change the compiler version to 3.7.0 version">
-      <created>1618509340144</created>
-      <option name="number" value="00009" />
-      <option name="presentableId" value="LOCAL-00009" />
-      <option name="project" value="LOCAL" />
-      <updated>1618509340144</updated>
-    </task>
-    <task id="LOCAL-00010" summary="提交 OSSRH 的提交地址">
-      <created>1618515214208</created>
-      <option name="number" value="00010" />
-      <option name="presentableId" value="LOCAL-00010" />
-      <option name="project" value="LOCAL" />
-      <updated>1618515214208</updated>
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-    <task id="LOCAL-00011" summary="Add name and URL before push to OSSRH">
-      <created>1618519278569</created>
-      <option name="number" value="00011" />
-      <option name="presentableId" value="LOCAL-00011" />
-      <option name="project" value="LOCAL" />
-      <updated>1618519278569</updated>
-    </task>
-    <task id="LOCAL-00012" summary="Upgrade to using JDK 11">
-      <created>1618519439477</created>
-      <option name="number" value="00012" />
-      <option name="presentableId" value="LOCAL-00012" />
-      <option name="project" value="LOCAL" />
-      <updated>1618519439477</updated>
-    </task>
-    <task id="LOCAL-00013" summary="Change name and description">
-      <created>1618519836247</created>
-      <option name="number" value="00013" />
-      <option name="presentableId" value="LOCAL-00013" />
-      <option name="project" value="LOCAL" />
-      <updated>1618519836247</updated>
-    </task>
-    <option name="localTasksCounter" value="14" />
     <servers />
   </component>
   <component name="TypeScriptGeneratedFilesManager">
     <option name="version" value="3" />
   </component>
-  <component name="Vcs.Log.Tabs.Properties">
-    <option name="TAB_STATES">
-      <map>
-        <entry key="MAIN">
-          <value>
-            <State />
-          </value>
-        </entry>
-      </map>
-    </option>
-    <option name="oldMeFiltersMigrated" value="true" />
-  </component>
-  <component name="VcsManagerConfiguration">
-    <MESSAGE value="更新 POM 文件" />
-    <MESSAGE value="Discourse Topic import" />
-    <MESSAGE value="项目的 POM 配置文件&#10;# Conflicts:&#10;#&#9;pom.xml" />
-    <MESSAGE value="Discourse" />
-    <MESSAGE value="添加忽略文件的内容" />
-    <MESSAGE value="完成所有的文件的提交，以便于下一步的代码演示和开发" />
-    <MESSAGE value="adjust the pom to make project can be compile" />
-    <MESSAGE value="DiscourseImportTest move to different project" />
-    <MESSAGE value="Change the compiler version to 3.7.0 version" />
-    <MESSAGE value="提交 OSSRH 的提交地址" />
-    <MESSAGE value="Add name and URL before push to OSSRH" />
-    <MESSAGE value="Upgrade to using JDK 11" />
-    <MESSAGE value="Change name and description" />
-    <option name="LAST_COMMIT_MESSAGE" value="Change name and description" />
-  </component>
 </project>
\ No newline at end of file
diff --git a/toolkits/codebank/src/test/java/com/ossez/toolkits/codebank/tests/LintcodeTest.java b/toolkits/codebank/src/test/java/com/ossez/toolkits/codebank/tests/LintcodeTest.java
index 082e4b6b62..21b25848e7 100644
--- a/toolkits/codebank/src/test/java/com/ossez/toolkits/codebank/tests/LintcodeTest.java
+++ b/toolkits/codebank/src/test/java/com/ossez/toolkits/codebank/tests/LintcodeTest.java
@@ -7,11 +7,11 @@ import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import com.ossez.toolkits.codebank.common.model.ListNode;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.ossez.lang.tutorial.models.ListNode;
 
 /**
  *