diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0cc2124
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.iml
+.idea/
diff --git a/.idea/.gitignore b/.idea/.gitignore
deleted file mode 100644
index c4cba32..0000000
--- a/.idea/.gitignore
+++ /dev/null
@@ -1,6 +0,0 @@
-# Default ignored files
-/shelf/
-/workspace.xml
-
-/.github
-/.gitignore
\ No newline at end of file
diff --git a/.idea/aws.xml b/.idea/aws.xml
deleted file mode 100644
index b63b642..0000000
--- a/.idea/aws.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="accountSettings">
-    <option name="activeRegion" value="us-east-1" />
-    <option name="recentlyUsedRegions">
-      <list>
-        <option value="us-east-1" />
-      </list>
-    </option>
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
deleted file mode 100644
index 919ce1f..0000000
--- a/.idea/codeStyles/Project.xml
+++ /dev/null
@@ -1,7 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <code_scheme name="Project" version="173">
-    <ScalaCodeStyleSettings>
-      <option name="MULTILINE_STRING_CLOSING_QUOTES_ON_NEW_LINE" value="true" />
-    </ScalaCodeStyleSettings>
-  </code_scheme>
-</component>
\ No newline at end of file
diff --git a/.idea/codeStyles/codeStyleConfig.xml b/.idea/codeStyles/codeStyleConfig.xml
deleted file mode 100644
index a55e7a1..0000000
--- a/.idea/codeStyles/codeStyleConfig.xml
+++ /dev/null
@@ -1,5 +0,0 @@
-<component name="ProjectCodeStyleConfiguration">
-  <state>
-    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
-  </state>
-</component>
\ No newline at end of file
diff --git a/.idea/effective-java.iml b/.idea/effective-java.iml
deleted file mode 100644
index d6ebd48..0000000
--- a/.idea/effective-java.iml
+++ /dev/null
@@ -1,9 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" inherit-compiler-output="true">
-    <exclude-output />
-    <content url="file://$MODULE_DIR$" />
-    <orderEntry type="inheritedJdk" />
-    <orderEntry type="sourceFolder" forTests="false" />
-  </component>
-</module>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
deleted file mode 100644
index 3a37236..0000000
--- a/.idea/misc.xml
+++ /dev/null
@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_14" project-jdk-name="14" project-jdk-type="JavaSDK">
-    <output url="file://$PROJECT_DIR$/out" />
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
deleted file mode 100644
index bb268fe..0000000
--- a/.idea/modules.xml
+++ /dev/null
@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/effective-java.iml" filepath="$PROJECT_DIR$/effective-java.iml" />
-    </modules>
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
deleted file mode 100644
index 35eb1dd..0000000
--- a/.idea/vcs.xml
+++ /dev/null
@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="" vcs="Git" />
-  </component>
-</project>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
deleted file mode 100644
index 20674b9..0000000
--- a/.idea/workspace.xml
+++ /dev/null
@@ -1,105 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="BranchesTreeState">
-    <expand>
-      <path>
-        <item name="ROOT" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="LOCAL_ROOT" type="e8cecc67:BranchNodeDescriptor" />
-      </path>
-      <path>
-        <item name="ROOT" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="REMOTE_ROOT" type="e8cecc67:BranchNodeDescriptor" />
-      </path>
-      <path>
-        <item name="ROOT" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="REMOTE_ROOT" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="GROUP_NODE:origin" type="e8cecc67:BranchNodeDescriptor" />
-      </path>
-      <path>
-        <item name="ROOT" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="REMOTE_ROOT" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="GROUP_NODE:origin" type="e8cecc67:BranchNodeDescriptor" />
-        <item name="GROUP_NODE:pyro" type="e8cecc67:BranchNodeDescriptor" />
-      </path>
-    </expand>
-    <select />
-  </component>
-  <component name="ChangeListManager">
-    <list default="true" id="38854f0e-77fb-4c3a-888b-37501636a1fb" name="Default Changelist" 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="CodeStyleSettingsInfer">
-    <option name="done" value="true" />
-  </component>
-  <component name="Git.Settings">
-    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
-  </component>
-  <component name="MavenImportPreferences">
-    <option name="generalSettings">
-      <MavenGeneralSettings>
-        <option name="mavenHome" value="$APPLICATION_HOME_DIR$/plugins/maven/lib/maven3" />
-      </MavenGeneralSettings>
-    </option>
-  </component>
-  <component name="ProjectCodeStyleSettingsMigration">
-    <option name="version" value="1" />
-  </component>
-  <component name="ProjectId" id="1nH1jaCRomxPQIVJ3Yaf3ZhTKr2" />
-  <component name="ProjectViewState">
-    <option name="autoscrollFromSource" value="true" />
-    <option name="flattenPackages" value="true" />
-    <option name="hideEmptyMiddlePackages" value="true" />
-    <option name="showLibraryContents" value="true" />
-    <option name="showVisibilityIcons" 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="aspect.path.notification.shown" value="true" />
-    <property name="last_opened_file_path" value="$PROJECT_DIR$" />
-    <property name="node.js.detected.package.eslint" value="true" />
-    <property name="node.js.detected.package.tslint" value="true" />
-    <property name="node.js.path.for.package.eslint" value="project" />
-    <property name="node.js.path.for.package.tslint" value="project" />
-    <property name="node.js.selected.package.eslint" value="(autodetect)" />
-    <property name="node.js.selected.package.tslint" value="(autodetect)" />
-    <property name="nodejs_package_manager_path" value="npm" />
-  </component>
-  <component name="RecentsManager">
-    <key name="MoveFile.RECENT_KEYS">
-      <recent name="$PROJECT_DIR$/chapter08/Item50" />
-    </key>
-  </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="38854f0e-77fb-4c3a-888b-37501636a1fb" name="Default Changelist" comment="" />
-      <created>1611032337920</created>
-      <option name="number" value="Default" />
-      <option name="presentableId" value="Default" />
-      <updated>1611032337920</updated>
-      <workItem from="1611220369885" duration="102000" />
-      <workItem from="1611220474695" duration="346000" />
-    </task>
-    <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>
-</project>
\ No newline at end of file
diff --git a/effective-java.iml b/effective-java.iml
deleted file mode 100644
index c44adcd..0000000
--- a/effective-java.iml
+++ /dev/null
@@ -1,11 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" inherit-compiler-output="true">
-    <exclude-output />
-    <content url="file://$MODULE_DIR$">
-      <sourceFolder url="file://$MODULE_DIR$/chapter02/item08" isTestSource="false" />
-    </content>
-    <orderEntry type="inheritedJdk" />
-    <orderEntry type="sourceFolder" forTests="false" />
-  </component>
-</module>
\ No newline at end of file