diff --git a/.idea/compiler.xml b/.idea/compiler.xml
new file mode 100644
index 00000000..1a795866
--- /dev/null
+++ b/.idea/compiler.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="springboot-in-10-steps" />
+      </profile>
+    </annotationProcessing>
+    <bytecodeTargetLevel>
+      <module name="springboot-in-10-steps" target="1.5" />
+    </bytecodeTargetLevel>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 00000000..0ebbb7fb
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/01.framework-introductions/springboot-in-10-steps/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK" />
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 00000000..f148e171
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/01.framework-introductions/springboot-in-10-steps/springboot-in-10-steps.iml" filepath="$PROJECT_DIR$/01.framework-introductions/springboot-in-10-steps/springboot-in-10-steps.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
new file mode 100644
index 00000000..035458c7
--- /dev/null
+++ b/.idea/workspace.xml
@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="AutoImportSettings">
+    <option name="autoReloadType" value="SELECTIVE" />
+  </component>
+  <component name="ChangeListManager">
+    <list default="true" id="efc378fa-2225-415b-bfe6-1469d56cbbf5" name="Changes" comment="" />
+    <option name="SHOW_DIALOG" value="false" />
+    <option name="HIGHLIGHT_CONFLICTS" value="true" />
+    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
+    <option name="LAST_RESOLUTION" value="IGNORE" />
+  </component>
+  <component name="Git.Settings">
+    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
+  </component>
+  <component name="ProjectId" id="1wLhfiBpMfxWhsbX1KQGQYCtzQa" />
+  <component name="ProjectViewState">
+    <option name="hideEmptyMiddlePackages" value="true" />
+    <option name="showLibraryContents" value="true" />
+  </component>
+  <component name="PropertiesComponent">
+    <property name="RunOnceActivity.OpenProjectViewOnStart" value="true" />
+    <property name="RunOnceActivity.ShowReadmeOnStart" value="true" />
+    <property name="WebServerToolWindowFactoryState" value="false" />
+    <property name="nodejs_package_manager_path" value="npm" />
+    <property name="settings.editor.selected.configurable" value="preferences.lookFeel" />
+  </component>
+  <component name="SpellCheckerSettings" RuntimeDictionaries="0" Folders="0" CustomDictionaries="0" DefaultDictionary="application-level" UseSingleDictionary="true" transferred="true" />
+  <component name="TaskManager">
+    <task active="true" id="Default" summary="Default task">
+      <changelist id="efc378fa-2225-415b-bfe6-1469d56cbbf5" name="Changes" comment="" />
+      <created>1628243883258</created>
+      <option name="number" value="Default" />
+      <option name="presentableId" value="Default" />
+      <updated>1628243883258</updated>
+      <workItem from="1628243885064" duration="1025000" />
+    </task>
+    <servers />
+  </component>
+  <component name="TypeScriptGeneratedFilesManager">
+    <option name="version" value="3" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/01.framework-introductions/springboot-in-10-steps/src/main/java/com/in28minutes/springboot/basics/springbootin10steps/SpringbootIn10StepsApplication.java b/01.framework-introductions/springboot-in-10-steps/src/main/java/com/in28minutes/springboot/basics/springbootin10steps/SpringbootIn10StepsApplication.java
index 9ca45084..b047b8e0 100644
--- a/01.framework-introductions/springboot-in-10-steps/src/main/java/com/in28minutes/springboot/basics/springbootin10steps/SpringbootIn10StepsApplication.java
+++ b/01.framework-introductions/springboot-in-10-steps/src/main/java/com/in28minutes/springboot/basics/springbootin10steps/SpringbootIn10StepsApplication.java
@@ -11,6 +11,9 @@ public class SpringbootIn10StepsApplication {
 	public static void main(String[] args) {
 		ApplicationContext applicationContext = 
 				SpringApplication.run(SpringbootIn10StepsApplication.class, args);
+
+		System.out.println("test comment.");
+		System.out.println("test comment.1");
 		
 		for (String name : applicationContext.getBeanDefinitionNames()) {
 			System.out.println(name);