diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..eaf91e2
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,3 @@
+# Default ignored files
+/shelf/
+/workspace.xml
diff --git a/.idea/.name b/.idea/.name
new file mode 100644
index 0000000..606cc6e
--- /dev/null
+++ b/.idea/.name
@@ -0,0 +1 @@
+chapter-10
\ No newline at end of file
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
new file mode 100644
index 0000000..167d83b
--- /dev/null
+++ b/.idea/gradle.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="#JAVA_HOME" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+          </set>
+        </option>
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..56684c1
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" project-jdk-name="17" project-jdk-type="JavaSDK" />
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..9661ac7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/git-hooks/pre-commit.sh b/git-hooks/pre-commit.sh
index e8e3042..0bee225 100644
--- a/git-hooks/pre-commit.sh
+++ b/git-hooks/pre-commit.sh
@@ -1 +1 @@
-.gradlew test
\ No newline at end of file
+gradlew spotlessCheck test
\ No newline at end of file
diff --git a/src/main/java/BirthdayChecker.java b/src/main/java/BirthdayChecker.java
index d09d159..b1f5e5f 100644
--- a/src/main/java/BirthdayChecker.java
+++ b/src/main/java/BirthdayChecker.java
@@ -1,8 +1,8 @@
-import java.time.LocalDateTime;
-
-public class BirthdayChecker {
-	boolean isBirthday() {
-		LocalDateTime today = LocalDateTime.now();
-		return today.getDayOfMonth() == 1 && today.getMonthValue() == 1;
-	}
-}
+import java.time.LocalDateTime;
+
+public class BirthdayChecker {
+	boolean isBirthday() {
+		LocalDateTime today = LocalDateTime.now();
+		return today.getDayOfMonth() == 1 && today.getMonthValue() == 1;
+	}
+}
diff --git a/src/main/java/Note.java b/src/main/java/Note.java
index 77d8c04..aef836f 100644
--- a/src/main/java/Note.java
+++ b/src/main/java/Note.java
@@ -1,37 +1,37 @@
-import io.reactivex.rxjava3.core.Completable;
-import io.reactivex.rxjava3.core.Scheduler;
-
-public class Note {
-	private final String DEFAULT_FILE_NAME = "note.txt";
-	private final TextFile textFile;
-	private BirthdayChecker birthdayChecker;
-
-	public Note(TextFile textFile) {
-		this.textFile = textFile;
-		this.create();
-	}
-
-	public Note(TextFile textFile, BirthdayChecker birthdayChecker) {
-		this.textFile = textFile;
-		this.birthdayChecker = birthdayChecker;
-	}
-
-	private void create() {
-		textFile.create(DEFAULT_FILE_NAME);
-	}
-
-	public void write(String content) {
-		if (birthdayChecker != null && birthdayChecker.isBirthday()) {
-			content += " 🎂";
-		}
-		textFile.write(DEFAULT_FILE_NAME, content);
-	}
-
-	public Completable writeAsync(String content, Scheduler scheduler) {
-		return Completable.fromAction(() -> write(content)).subscribeOn(scheduler);
-	}
-
-	public String read() {
-		return textFile.read(DEFAULT_FILE_NAME);
-	}
-}
+import io.reactivex.rxjava3.core.Completable;
+import io.reactivex.rxjava3.core.Scheduler;
+
+public class Note {
+	private final String DEFAULT_FILE_NAME = "note.txt";
+	private final TextFile textFile;
+	private BirthdayChecker birthdayChecker;
+
+	public Note(TextFile textFile) {
+		this.textFile = textFile;
+		this.create();
+	}
+
+	public Note(TextFile textFile, BirthdayChecker birthdayChecker) {
+		this.textFile = textFile;
+		this.birthdayChecker = birthdayChecker;
+	}
+
+	private void create() {
+		textFile.create(DEFAULT_FILE_NAME);
+	}
+
+	public void write(String content) {
+		if (birthdayChecker != null && birthdayChecker.isBirthday()) {
+			content += " 🎂";
+		}
+		textFile.write(DEFAULT_FILE_NAME, content);
+	}
+
+	public Completable writeAsync(String content, Scheduler scheduler) {
+		return Completable.fromAction(() -> write(content)).subscribeOn(scheduler);
+	}
+
+	public String read() {
+		return textFile.read(DEFAULT_FILE_NAME);
+	}
+}
diff --git a/src/main/java/TextFile.java b/src/main/java/TextFile.java
index a4c9677..1f559f1 100644
--- a/src/main/java/TextFile.java
+++ b/src/main/java/TextFile.java
@@ -1,38 +1,38 @@
-import java.io.FileReader;
-import java.io.FileWriter;
-
-public class TextFile {
-
-	public void create(String fileName) {
-		try {
-			FileWriter fileWriter = new FileWriter(fileName);
-			fileWriter.close();
-		} catch (Exception ignored) {
-
-		}
-	}
-
-	public void write(String fileName, String content) {
-		try {
-			FileWriter fileWriter = new FileWriter(fileName, true);
-			fileWriter.write(content);
-			fileWriter.write("\n");
-			fileWriter.close();
-		} catch (Exception ignored) {
-		}
-	}
-
-	public String read(String fileName) {
-		StringBuilder content = new StringBuilder();
-		try {
-			FileReader fileReader = new FileReader(fileName);
-			int i;
-			while ((i = fileReader.read()) != -1) {
-				content.append((char) i);
-			}
-			fileReader.close();
-		} catch (Exception ignored) {
-		}
-		return content.toString().trim();
-	}
-}
+import java.io.FileReader;
+import java.io.FileWriter;
+
+public class TextFile {
+
+	public void create(String fileName) {
+		try {
+			FileWriter fileWriter = new FileWriter(fileName);
+			fileWriter.close();
+		} catch (Exception ignored) {
+
+		}
+	}
+
+	public void write(String fileName, String content) {
+		try {
+			FileWriter fileWriter = new FileWriter(fileName, true);
+			fileWriter.write(content);
+			fileWriter.write("\n");
+			fileWriter.close();
+		} catch (Exception ignored) {
+		}
+	}
+
+	public String read(String fileName) {
+		StringBuilder content = new StringBuilder();
+		try {
+			FileReader fileReader = new FileReader(fileName);
+			int i;
+			while ((i = fileReader.read()) != -1) {
+				content.append((char) i);
+			}
+			fileReader.close();
+		} catch (Exception ignored) {
+		}
+		return content.toString().trim();
+	}
+}
diff --git a/src/test/java/NoteTest.java b/src/test/java/NoteTest.java
index 32af7cd..1bc3907 100644
--- a/src/test/java/NoteTest.java
+++ b/src/test/java/NoteTest.java
@@ -1,93 +1,93 @@
-import io.reactivex.rxjava3.schedulers.Schedulers;
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.*;
-
-class NoteTest {
-
-	@Test
-	@DisplayName("given initial note, my note should be empty")
-	void initialNoteShouldBeEmpty() {
-		TextFile textFile = mock(TextFile.class);
-		when(textFile.read(any())).thenReturn("");
-		Note note = new Note(textFile);
-
-		String expected = "";
-		String actual = note.read();
-		assertEquals(expected, actual);
-	}
-
-	@Test
-	@DisplayName("create reading book note, my note should return reading book")
-	void createReadingNote() {
-		TextFile textFile = mock(TextFile.class);
-		when(textFile.read(any())).thenReturn("Reading book");
-		Note note = new Note(textFile);
-
-		note.write("Reading book");
-
-		String expected = "Reading book";
-		assertEquals(expected, note.read());
-	}
-
-	@Test
-	@DisplayName("my default note file should be note.txt")
-	void defaultNoteFile() {
-		TextFile textFile = mock(TextFile.class);
-		Note note = new Note(textFile);
-
-		String expected = "note.txt";
-		verify(textFile).create(expected);
-	}
-
-	@Test
-	@DisplayName("initial note should create note.txt only one file")
-	void createNoteFileOnlyOneTime() {
-		TextFile textFile = mock(TextFile.class);
-		Note note = new Note(textFile);
-
-		int expected = 1;
-		verify(textFile, times(1)).create(any());
-	}
-
-	@Test
-	@DisplayName("write reading note should call write method")
-	void writeNote() {
-		TextFile textFile = mock(TextFile.class);
-		Note note = new Note(textFile);
-
-		note.write("Reading book");
-
-		verify(textFile).write("note.txt", "Reading book");
-	}
-
-	@Test
-	@DisplayName("given today is my birthday write reading note and my note should contain 🎂")
-	void writeNoteOnMyBirthday() {
-		TextFile textFile = mock(TextFile.class);
-		BirthdayChecker birthdayChecker = mock(BirthdayChecker.class);
-		when(birthdayChecker.isBirthday()).thenReturn(true);
-		Note note = new Note(textFile, birthdayChecker);
-
-		note.write("Reading book");
-
-		String expected = "Reading book";
-		verify(textFile).write("note.txt", expected);
-	}
-
-	@Test
-	@DisplayName("given write reading note async should success")
-	void writeAsyncNoteShouldSuccess() {
-		TextFile textFile = mock(TextFile.class);
-		BirthdayChecker birthdayChecker = mock(BirthdayChecker.class);
-		when(birthdayChecker.isBirthday()).thenReturn(true);
-		Note note = new Note(textFile, birthdayChecker);
-
-		note.writeAsync("Reading book", Schedulers.trampoline())
-			.test()
-			.assertComplete();
-	}
-}
+import io.reactivex.rxjava3.schedulers.Schedulers;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+class NoteTest {
+
+	@Test
+	@DisplayName("given initial note, my note should be empty")
+	void initialNoteShouldBeEmpty() {
+		TextFile textFile = mock(TextFile.class);
+		when(textFile.read(any())).thenReturn("");
+		Note note = new Note(textFile);
+
+		String expected = "";
+		String actual = note.read();
+		assertEquals(expected, actual);
+	}
+
+	@Test
+	@DisplayName("create reading book note, my note should return reading book")
+	void createReadingNote() {
+		TextFile textFile = mock(TextFile.class);
+		when(textFile.read(any())).thenReturn("Reading book");
+		Note note = new Note(textFile);
+
+		note.write("Reading book");
+
+		String expected = "Reading book";
+		assertEquals(expected, note.read());
+	}
+
+	@Test
+	@DisplayName("my default note file should be note.txt")
+	void defaultNoteFile() {
+		TextFile textFile = mock(TextFile.class);
+		Note note = new Note(textFile);
+
+		String expected = "note.txt";
+		verify(textFile).create(expected);
+	}
+
+	@Test
+	@DisplayName("initial note should create note.txt only one file")
+	void createNoteFileOnlyOneTime() {
+		TextFile textFile = mock(TextFile.class);
+		Note note = new Note(textFile);
+
+		int expected = 1;
+		verify(textFile, times(1)).create(any());
+	}
+
+	@Test
+	@DisplayName("write reading note should call write method")
+	void writeNote() {
+		TextFile textFile = mock(TextFile.class);
+		Note note = new Note(textFile);
+
+		note.write("Reading book");
+
+		verify(textFile).write("note.txt", "Reading book");
+	}
+
+	@Test
+	@DisplayName("given today is my birthday write reading note and my note should contain 🎂")
+	void writeNoteOnMyBirthday() {
+		TextFile textFile = mock(TextFile.class);
+		BirthdayChecker birthdayChecker = mock(BirthdayChecker.class);
+		when(birthdayChecker.isBirthday()).thenReturn(true);
+		Note note = new Note(textFile, birthdayChecker);
+
+		note.write("Reading book");
+
+		String expected = "Reading book 🎂";
+		verify(textFile).write("note.txt", expected);
+	}
+
+	@Test
+	@DisplayName("given write reading note async should success")
+	void writeAsyncNoteShouldSuccess() {
+		TextFile textFile = mock(TextFile.class);
+		BirthdayChecker birthdayChecker = mock(BirthdayChecker.class);
+		when(birthdayChecker.isBirthday()).thenReturn(true);
+		Note note = new Note(textFile, birthdayChecker);
+
+		note.writeAsync("Reading book", Schedulers.trampoline())
+			.test()
+			.assertComplete();
+	}
+}