diff --git a/Tutorial_03/.gitignore b/Tutorial_03/.gitignore
new file mode 100644
index 0000000..e301d78
--- /dev/null
+++ b/Tutorial_03/.gitignore
@@ -0,0 +1,131 @@
+## Seb's .gitignore template
+# You can find the most up-to-date version at https://go.sebastiano.dev/gitignore
+# Partly based on templates by https://plugins.jetbrains.com/plugin/7495--ignore
+# Released under a CC-0 License https://creativecommons.org/share-your-work/public-domain/cc0/
+
+### Windows template
+# Windows thumbnail cache files
+Thumbs.db
+Thumbs.db:encryptable
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+### macOS template
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### Linux template
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+*.iml
+*.ipr
+*.iws
+/.idea/*
+
+# Exclude non-user-specific stuff
+!.idea/.name
+!.idea/codeInsightSettings.xml
+!.idea/codeStyles/
+!.idea/copyright/
+!.idea/dataSources.xml
+!.idea/detekt.xml
+!.idea/encodings.xml
+!.idea/externalDependencies.xml
+!.idea/file.template.settings.xml
+!.idea/fileTemplates/
+!.idea/icon.svg
+!.idea/inspectionProfiles/
+!.idea/runConfigurations/
+!.idea/scopes/
+!.idea/vcs.xml
+
+### Kotlin template
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+### Gradle template
+.gradle
+
+# Note that you may need to exclude by hand other folders
+# named build if necessary (e.g., in src/)
+**/build/
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle/wrapper/gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
diff --git a/Tutorial_03/.idea/.name b/Tutorial_03/.idea/.name
new file mode 100644
index 0000000..2ab37f8
--- /dev/null
+++ b/Tutorial_03/.idea/.name
@@ -0,0 +1 @@
+03_code
\ No newline at end of file
diff --git a/Tutorial_03/.idea/vcs.xml b/Tutorial_03/.idea/vcs.xml
new file mode 100644
index 0000000..f245aa7
--- /dev/null
+++ b/Tutorial_03/.idea/vcs.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$/.." vcs="Git" />
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/Tutorial_03/README.md b/Tutorial_03/README.md
new file mode 100644
index 0000000..6b99ead
--- /dev/null
+++ b/Tutorial_03/README.md
@@ -0,0 +1 @@
+각자 작업하신거 `./{LectureName}/` 폴더 만드시고 PR해주세요
\ No newline at end of file
diff --git a/Tutorial_03/app/.gitignore b/Tutorial_03/app/.gitignore
new file mode 100644
index 0000000..42afabf
--- /dev/null
+++ b/Tutorial_03/app/.gitignore
@@ -0,0 +1 @@
+/build
\ No newline at end of file
diff --git a/Tutorial_03/app/build.gradle.kts b/Tutorial_03/app/build.gradle.kts
new file mode 100644
index 0000000..61dcbc8
--- /dev/null
+++ b/Tutorial_03/app/build.gradle.kts
@@ -0,0 +1,50 @@
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+}
+
+android {
+    namespace = "com.example.swpp.cloud_code"
+    compileSdk = 36
+
+    defaultConfig {
+        applicationId = "com.example.swpp.cloud_code"
+        minSdk = 24
+        targetSdk = 36
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+    kotlinOptions {
+        jvmTarget = "11"
+    }
+}
+
+dependencies {
+
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.material)
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+
+    implementation("com.squareup.retrofit2:retrofit:2.9.0")
+    implementation("com.google.code.gson:gson:2.8.9")
+    implementation("com.squareup.retrofit2:converter-gson:2.4.0")
+}
\ No newline at end of file
diff --git a/Tutorial_03/app/proguard-rules.pro b/Tutorial_03/app/proguard-rules.pro
new file mode 100644
index 0000000..481bb43
--- /dev/null
+++ b/Tutorial_03/app/proguard-rules.pro
@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
\ No newline at end of file
diff --git a/Tutorial_03/app/src/androidTest/java/com/example/swpp/cloud_code/ExampleInstrumentedTest.kt b/Tutorial_03/app/src/androidTest/java/com/example/swpp/cloud_code/ExampleInstrumentedTest.kt
new file mode 100644
index 0000000..7c2ebb5
--- /dev/null
+++ b/Tutorial_03/app/src/androidTest/java/com/example/swpp/cloud_code/ExampleInstrumentedTest.kt
@@ -0,0 +1,24 @@
+package com.example.swpp.cloud_code
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.example.swpp.cloud_code", appContext.packageName)
+    }
+}
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/AndroidManifest.xml b/Tutorial_03/app/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..01d3fef
--- /dev/null
+++ b/Tutorial_03/app/src/main/AndroidManifest.xml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+    <uses-permission android:name="android.permission.INTERNET"/>
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme._03_code"
+        android:usesCleartextTraffic="true">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+
+</manifest>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/CodeMessageResponse.kt b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/CodeMessageResponse.kt
new file mode 100644
index 0000000..5666a34
--- /dev/null
+++ b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/CodeMessageResponse.kt
@@ -0,0 +1,11 @@
+package com.example.swpp.cloud_code
+
+import com.google.gson.annotations.SerializedName
+
+data class CodeMessageResponse(
+    @SerializedName("code")
+    val code: Int,
+
+    @SerializedName("message")
+    val message: String
+)
diff --git a/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/MainActivity.kt b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/MainActivity.kt
new file mode 100644
index 0000000..6e4f996
--- /dev/null
+++ b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/MainActivity.kt
@@ -0,0 +1,59 @@
+package com.example.swpp.cloud_code
+
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+import android.widget.Toast
+import androidx.appcompat.app.AppCompatActivity
+import retrofit2.Call
+import retrofit2.Callback
+import retrofit2.Response
+
+class MainActivity : AppCompatActivity() {
+
+    private lateinit var nameInput: TextView
+    private lateinit var idInput: TextView
+    private lateinit var writeButton: Button
+    private lateinit var targetNameInput: TextView
+    private lateinit var readButton: Button
+    private lateinit var targetNameOutput: TextView
+    private lateinit var idText: TextView
+
+    private lateinit var service: ServiceApi
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+
+        nameInput = findViewById(R.id.NameInput)
+        idInput = findViewById(R.id.IdInput)
+        writeButton = findViewById(R.id.WriteBtn)
+        targetNameInput = findViewById(R.id.TargetNameInput)
+        readButton = findViewById(R.id.ReadBtn)
+        targetNameOutput = findViewById(R.id.TargetNameOutput)
+        idText = findViewById(R.id.IdOutput)
+
+        service = RetrofitClient.getClient().create(ServiceApi::class.java)
+
+        writeButton.setOnClickListener {
+            val userName = nameInput.text.toString()
+            val userId = idInput.text.toString()
+
+            val requestData = NameIdData(userName, userId)
+
+            service.userWrite(requestData).enqueue(object : Callback<CodeMessageResponse> {
+                override fun onResponse(
+                    call: Call<CodeMessageResponse>,
+                    response: Response<CodeMessageResponse>
+                ) {
+                    val result = response.body()
+                    Toast.makeText(this@MainActivity, result?.message, Toast.LENGTH_SHORT).show()
+                }
+
+                override fun onFailure(call: Call<CodeMessageResponse>, t: Throwable) {
+                    Toast.makeText(this@MainActivity, "Write Error", Toast.LENGTH_SHORT).show()
+                }
+            })
+        }
+    }
+}
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/NameIdData.kt b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/NameIdData.kt
new file mode 100644
index 0000000..7fda75c
--- /dev/null
+++ b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/NameIdData.kt
@@ -0,0 +1,11 @@
+package com.example.swpp.cloud_code
+
+import com.google.gson.annotations.SerializedName
+
+data class NameIdData(
+    @SerializedName("userName")
+    val userName: String,
+
+    @SerializedName("userId")
+    val userId: String
+)
diff --git a/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/RetrofitClient.kt b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/RetrofitClient.kt
new file mode 100644
index 0000000..87f49bf
--- /dev/null
+++ b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/RetrofitClient.kt
@@ -0,0 +1,20 @@
+package com.example.swpp.cloud_code
+
+import retrofit2.Retrofit
+import retrofit2.converter.gson.GsonConverterFactory
+
+object RetrofitClient {
+    private const val BASE_URL = "http://ec2-16-184-15-144.ap-northeast-2.compute.amazonaws.com:3000" // TODO: Replace with your actual EC2 endpoint
+
+    private var retrofit: Retrofit? = null
+
+    fun getClient(): Retrofit {
+        if (retrofit == null) {
+            retrofit = Retrofit.Builder()
+                    .baseUrl(BASE_URL)
+                .addConverterFactory(GsonConverterFactory.create())
+                .build()
+        }
+        return retrofit!!
+    }
+}
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/ServiceApi.kt b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/ServiceApi.kt
new file mode 100644
index 0000000..bf12cdc
--- /dev/null
+++ b/Tutorial_03/app/src/main/java/com/example/swpp/cloud_code/ServiceApi.kt
@@ -0,0 +1,10 @@
+package com.example.swpp.cloud_code
+
+import retrofit2.Call
+import retrofit2.http.Body
+import retrofit2.http.POST
+
+interface ServiceApi {
+    @POST("/user/write")
+    fun userWrite(@Body data: NameIdData): Call<CodeMessageResponse>
+}
diff --git a/Tutorial_03/app/src/main/res/drawable/btn_bg.xml b/Tutorial_03/app/src/main/res/drawable/btn_bg.xml
new file mode 100644
index 0000000..5ff570b
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/drawable/btn_bg.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Background shape with rounded corners -->
+    <item>
+        <shape android:shape="rectangle">
+            <corners android:radius="15dp" />
+            <gradient
+                android:angle="0"
+                android:startColor="#4776E6"
+                android:endColor="#8E54E9"
+                android:type="linear" />
+        </shape>
+    </item>
+</layer-list>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/drawable/edittext_bg.xml b/Tutorial_03/app/src/main/res/drawable/edittext_bg.xml
new file mode 100644
index 0000000..5250d9a
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/drawable/edittext_bg.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:state_focused="false" android:drawable="@drawable/edittext_unfocused"/>
+    <item android:state_focused="true" android:drawable="@drawable/edittext_focused"/>
+</selector>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/drawable/edittext_focused.xml b/Tutorial_03/app/src/main/res/drawable/edittext_focused.xml
new file mode 100644
index 0000000..a1e93f6
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/drawable/edittext_focused.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Background shape with rounded corners (no fill) -->
+    <item>
+        <shape android:shape="rectangle">
+            <solid android:color="@android:color/transparent" />
+            <corners android:radius="15dp" />
+            <stroke
+                android:width="1sp"
+                android:color="#4776E6" />
+        </shape>
+    </item>
+</layer-list>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/drawable/edittext_unfocused.xml b/Tutorial_03/app/src/main/res/drawable/edittext_unfocused.xml
new file mode 100644
index 0000000..99b3b41
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/drawable/edittext_unfocused.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Background shape with rounded corners (no fill) -->
+    <item>
+        <shape android:shape="rectangle">
+            <solid android:color="@android:color/transparent" />
+            <corners android:radius="15dp" />
+            <stroke
+                android:width="1sp"
+                android:color="#887e7e" />
+        </shape>
+    </item>
+</layer-list>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/drawable/ic_launcher_background.xml b/Tutorial_03/app/src/main/res/drawable/ic_launcher_background.xml
new file mode 100644
index 0000000..07d5da9
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/drawable/ic_launcher_background.xml
@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#3DDC84"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>
diff --git a/Tutorial_03/app/src/main/res/drawable/ic_launcher_foreground.xml b/Tutorial_03/app/src/main/res/drawable/ic_launcher_foreground.xml
new file mode 100644
index 0000000..2b068d1
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/drawable/ic_launcher_foreground.xml
@@ -0,0 +1,30 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="85.84757"
+                android:endY="92.4963"
+                android:startX="42.9492"
+                android:startY="49.59793"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/layout/activity_main.xml b/Tutorial_03/app/src/main/res/layout/activity_main.xml
new file mode 100644
index 0000000..42c6e9c
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/layout/activity_main.xml
@@ -0,0 +1,104 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:padding="30dp"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity">
+
+    <TextView
+        android:id="@+id/WriteText"
+        style="@style/TitleText"
+        android:paddingVertical="0dp"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Write Student Information"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <androidx.appcompat.widget.AppCompatEditText
+        android:id="@+id/NameInput"
+        style="@style/EditText"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="Name"
+        android:inputType="text"
+        app:layout_constraintTop_toBottomOf="@id/WriteText" />
+
+    <androidx.appcompat.widget.AppCompatEditText
+        android:id="@+id/IdInput"
+        style="@style/EditText"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="Student ID"
+        android:inputType="text"
+        app:layout_constraintTop_toBottomOf="@id/NameInput" />
+
+    <androidx.appcompat.widget.AppCompatButton
+        android:id="@+id/WriteBtn"
+        style="@style/Button"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="Write"
+        android:background="@drawable/btn_bg"
+        app:layout_constraintTop_toBottomOf="@id/IdInput" />
+
+
+    <TextView
+        android:id="@+id/ReadText"
+        style="@style/TitleText"
+        android:paddingVertical="0dp"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Read Student ID"
+        android:layout_margin="25dp"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/WriteBtn" />
+
+    <androidx.appcompat.widget.AppCompatEditText
+        android:id="@+id/TargetNameInput"
+        style="@style/EditText"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="Target Name"
+        android:inputType="text"
+        app:layout_constraintTop_toBottomOf="@id/ReadText" />
+
+    <androidx.appcompat.widget.AppCompatButton
+        android:id="@+id/ReadBtn"
+        style="@style/Button"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="Read"
+        android:background="@drawable/btn_bg"
+        app:layout_constraintTop_toBottomOf="@id/TargetNameInput" />
+
+    <TextView
+        android:id="@+id/TargetNameOutput"
+        style="@style/TitleText"
+        android:paddingVertical="0dp"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Target Name"
+        android:layout_margin="40sp"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/ReadBtn" />
+
+    <TextView
+        android:id="@+id/IdOutput"
+        style="@style/OutputText"
+        android:paddingVertical="0dp"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="0000-00000"
+        android:layout_margin="25dp"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/TargetNameOutput" />
+
+
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml b/Tutorial_03/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
new file mode 100644
index 0000000..6f3b755
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+    <monochrome android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml b/Tutorial_03/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
new file mode 100644
index 0000000..6f3b755
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+    <monochrome android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/mipmap-hdpi/ic_launcher.webp b/Tutorial_03/app/src/main/res/mipmap-hdpi/ic_launcher.webp
new file mode 100644
index 0000000..c209e78
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-hdpi/ic_launcher.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-hdpi/ic_launcher_round.webp b/Tutorial_03/app/src/main/res/mipmap-hdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..b2dfe3d
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-hdpi/ic_launcher_round.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-mdpi/ic_launcher.webp b/Tutorial_03/app/src/main/res/mipmap-mdpi/ic_launcher.webp
new file mode 100644
index 0000000..4f0f1d6
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-mdpi/ic_launcher.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-mdpi/ic_launcher_round.webp b/Tutorial_03/app/src/main/res/mipmap-mdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..62b611d
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-mdpi/ic_launcher_round.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-xhdpi/ic_launcher.webp b/Tutorial_03/app/src/main/res/mipmap-xhdpi/ic_launcher.webp
new file mode 100644
index 0000000..948a307
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-xhdpi/ic_launcher.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-xhdpi/ic_launcher_round.webp b/Tutorial_03/app/src/main/res/mipmap-xhdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..1b9a695
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-xhdpi/ic_launcher_round.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-xxhdpi/ic_launcher.webp b/Tutorial_03/app/src/main/res/mipmap-xxhdpi/ic_launcher.webp
new file mode 100644
index 0000000..28d4b77
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-xxhdpi/ic_launcher.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.webp b/Tutorial_03/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..9287f50
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-xxxhdpi/ic_launcher.webp b/Tutorial_03/app/src/main/res/mipmap-xxxhdpi/ic_launcher.webp
new file mode 100644
index 0000000..aa7d642
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-xxxhdpi/ic_launcher.webp differ
diff --git a/Tutorial_03/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.webp b/Tutorial_03/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..9126ae3
Binary files /dev/null and b/Tutorial_03/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.webp differ
diff --git a/Tutorial_03/app/src/main/res/values/colors.xml b/Tutorial_03/app/src/main/res/values/colors.xml
new file mode 100644
index 0000000..c8524cd
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/values/colors.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="black">#FF000000</color>
+    <color name="white">#FFFFFFFF</color>
+</resources>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/values/strings.xml b/Tutorial_03/app/src/main/res/values/strings.xml
new file mode 100644
index 0000000..680f78f
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/values/strings.xml
@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">CloudComputingTutorial</string>
+</resources>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/values/styles.xml b/Tutorial_03/app/src/main/res/values/styles.xml
new file mode 100644
index 0000000..a11a04e
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/values/styles.xml
@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="TitleText">
+        <item name="android:textStyle">bold</item>
+        <item name="android:textSize">25sp</item>
+    </style>
+
+    <style name="OutputText">
+        <item name="android:textStyle">bold</item>
+        <item name="android:textSize">25sp</item>
+        <item name="android:textColor">#FF0000</item>
+    </style>
+
+    <style name="SmallText">
+        <item name="android:textSize">12sp</item>
+    </style>
+
+    <style name="TextBtn" parent="SmallText">
+        <item name="android:textStyle">italic</item>
+    </style>
+
+    <style name="TextBtnRed" parent="TextBtn">
+        <item name="android:textColor">#FF0000</item>
+    </style>
+
+    <style name="Button">
+        <item name="android:background">@drawable/btn_bg</item>
+        <item name="android:textColor">@color/white</item>
+        <item name="android:layout_marginTop">10dp</item>
+        <item name="android:textSize">20sp</item>
+        <item name="android:textStyle">bold</item>
+        <item name="android:padding">15dp</item>
+    </style>
+
+    <style name="EditText">
+        <item name="android:background">@drawable/edittext_bg</item>
+        <item name="android:layout_marginTop">10dp</item>
+        <item name="android:padding">20dp</item>
+        <item name="android:textSize">20sp</item>
+    </style>
+
+
+</resources>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/values/themes.xml b/Tutorial_03/app/src/main/res/values/themes.xml
new file mode 100644
index 0000000..fbef2e5
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/values/themes.xml
@@ -0,0 +1,9 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <!-- Base application theme. -->
+    <style name="Base.Theme._03_code" parent="Theme.Material3.DayNight.NoActionBar">
+        <!-- Customize your light theme here. -->
+        <!-- <item name="colorPrimary">@color/my_light_primary</item> -->
+    </style>
+
+    <style name="Theme._03_code" parent="Base.Theme._03_code" />
+</resources>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/xml/backup_rules.xml b/Tutorial_03/app/src/main/res/xml/backup_rules.xml
new file mode 100644
index 0000000..4df9255
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/xml/backup_rules.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+   Sample backup rules file; uncomment and customize as necessary.
+   See https://developer.android.com/guide/topics/data/autobackup
+   for details.
+   Note: This file is ignored for devices older than API 31
+   See https://developer.android.com/about/versions/12/backup-restore
+-->
+<full-backup-content>
+    <!--
+   <include domain="sharedpref" path="."/>
+   <exclude domain="sharedpref" path="device.xml"/>
+-->
+</full-backup-content>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/main/res/xml/data_extraction_rules.xml b/Tutorial_03/app/src/main/res/xml/data_extraction_rules.xml
new file mode 100644
index 0000000..9ee9997
--- /dev/null
+++ b/Tutorial_03/app/src/main/res/xml/data_extraction_rules.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+   Sample data extraction rules file; uncomment and customize as necessary.
+   See https://developer.android.com/about/versions/12/backup-restore#xml-changes
+   for details.
+-->
+<data-extraction-rules>
+    <cloud-backup>
+        <!-- TODO: Use <include> and <exclude> to control what is backed up.
+        <include .../>
+        <exclude .../>
+        -->
+    </cloud-backup>
+    <!--
+    <device-transfer>
+        <include .../>
+        <exclude .../>
+    </device-transfer>
+    -->
+</data-extraction-rules>
\ No newline at end of file
diff --git a/Tutorial_03/app/src/test/java/com/example/swpp/cloud_code/ExampleUnitTest.kt b/Tutorial_03/app/src/test/java/com/example/swpp/cloud_code/ExampleUnitTest.kt
new file mode 100644
index 0000000..780caef
--- /dev/null
+++ b/Tutorial_03/app/src/test/java/com/example/swpp/cloud_code/ExampleUnitTest.kt
@@ -0,0 +1,17 @@
+package com.example.swpp.cloud_code
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+}
\ No newline at end of file
diff --git a/Tutorial_03/build.gradle.kts b/Tutorial_03/build.gradle.kts
new file mode 100644
index 0000000..922f551
--- /dev/null
+++ b/Tutorial_03/build.gradle.kts
@@ -0,0 +1,5 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+plugins {
+    alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.kotlin.android) apply false
+}
\ No newline at end of file
diff --git a/Tutorial_03/gradle.properties b/Tutorial_03/gradle.properties
new file mode 100644
index 0000000..20e2a01
--- /dev/null
+++ b/Tutorial_03/gradle.properties
@@ -0,0 +1,23 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. For more details, visit
+# https://developer.android.com/r/tools/gradle-multi-project-decoupled-projects
+# org.gradle.parallel=true
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app's APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+# Kotlin code style for this project: "official" or "obsolete":
+kotlin.code.style=official
+# Enables namespacing of each library's R class so that its R class includes only the
+# resources declared in the library itself and none from the library's dependencies,
+# thereby reducing the size of the R class for that library
+android.nonTransitiveRClass=true
\ No newline at end of file
diff --git a/Tutorial_03/gradle/libs.versions.toml b/Tutorial_03/gradle/libs.versions.toml
new file mode 100644
index 0000000..8e5b65c
--- /dev/null
+++ b/Tutorial_03/gradle/libs.versions.toml
@@ -0,0 +1,22 @@
+[versions]
+agp = "8.12.0"
+kotlin = "2.0.21"
+coreKtx = "1.10.1"
+junit = "4.13.2"
+junitVersion = "1.1.5"
+espressoCore = "3.5.1"
+appcompat = "1.6.1"
+material = "1.10.0"
+
+[libraries]
+androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+junit = { group = "junit", name = "junit", version.ref = "junit" }
+androidx-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
+androidx-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCore" }
+androidx-appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "appcompat" }
+material = { group = "com.google.android.material", name = "material", version.ref = "material" }
+
+[plugins]
+android-application = { id = "com.android.application", version.ref = "agp" }
+kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+
diff --git a/Tutorial_03/gradle/wrapper/gradle-wrapper.jar b/Tutorial_03/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..e708b1c
Binary files /dev/null and b/Tutorial_03/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/Tutorial_03/gradle/wrapper/gradle-wrapper.properties b/Tutorial_03/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..492e078
--- /dev/null
+++ b/Tutorial_03/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Tue Aug 05 00:15:51 KST 2025
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.13-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/Tutorial_03/gradlew b/Tutorial_03/gradlew
new file mode 100644
index 0000000..4f906e0
--- /dev/null
+++ b/Tutorial_03/gradlew
@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
diff --git a/Tutorial_03/gradlew.bat b/Tutorial_03/gradlew.bat
new file mode 100644
index 0000000..ac1b06f
--- /dev/null
+++ b/Tutorial_03/gradlew.bat
@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/Tutorial_03/local.properties b/Tutorial_03/local.properties
new file mode 100644
index 0000000..d499f19
--- /dev/null
+++ b/Tutorial_03/local.properties
@@ -0,0 +1,10 @@
+## This file is automatically generated by Android Studio.
+# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
+#
+# This file should *NOT* be checked into Version Control Systems,
+# as it contains information specific to your local configuration.
+#
+# Location of the SDK. This is only used by Gradle.
+# For customization when using a Version Control System, please read the
+# header note.
+sdk.dir=C\:\\Users\\hscor\\AppData\\Local\\Android\\Sdk
\ No newline at end of file
diff --git a/Tutorial_03/settings.gradle.kts b/Tutorial_03/settings.gradle.kts
new file mode 100644
index 0000000..26ebf84
--- /dev/null
+++ b/Tutorial_03/settings.gradle.kts
@@ -0,0 +1,24 @@
+pluginManagement {
+    repositories {
+        google {
+            content {
+                includeGroupByRegex("com\\.android.*")
+                includeGroupByRegex("com\\.google.*")
+                includeGroupByRegex("androidx.*")
+            }
+        }
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "03_code"
+include(":app")
+ 
\ No newline at end of file
diff --git a/main.js b/main.js
new file mode 100644
index 0000000..2f8c737
--- /dev/null
+++ b/main.js
@@ -0,0 +1,84 @@
+const mysql = require('mysql');
+const express = require('express');
+const bodyParser = require('body-parser');
+const app = express();
+const port = 3000;
+
+app.set("port", port);
+app.use(bodyParser.json());
+app.use(bodyParser.urlencoded({extended: true}));
+
+app.get('/', (req, res) => {
+  res.send('Hello World!');
+});
+
+app.listen(port, () => {
+    console.log('Server Runnning...');
+});
+
+const connection = mysql.createConnection({
+    host: "Put your RDS endpoint here",
+    user: "RDS user name",
+    database: "example",
+    password: "RDS user password",
+    port: 3306
+});
+
+app.post('/user/write', (req, res) => {
+    console.log(req.body);
+    const userName = req.body.userName;
+    const userId = req.body.userId;
+
+    const sql = 'INSERT INTO Users (UserName, UserId) VALUES (?, ?)';
+    const params = [userName, userId];
+
+    connection.query(sql, params, (err, result) => {
+        let resultCode = 404;
+        let message = 'Error occured';
+
+        if (err) {
+            console.log(err);
+        } else {
+            resultCode = 200;
+            message = 'Write Success';
+            console.log(message);
+        }
+
+        res.json({
+            'code': resultCode,
+            'message': message
+        });
+    });
+});
+
+app.post('/user/read', (req, res) => {
+    console.log(req.body);
+    const userName = req.body.userName;
+    const sql = 'select * from Users where UserName = ?';
+    const params = [userName];
+
+    connection.query(sql, params, (err, result) => {
+        let resultCode = 404;
+        let message = 'Error occured';
+        let userId = -1;
+
+        if (err) {
+            console.log(err);
+        } else {
+            if (result.length === 0) {
+                resultCode = 404;
+                message = "User '" + userName + "' does not exist";
+                userId = "0000-00000";
+            } else {
+                resultCode = 200;
+                message = 'Read Success';
+                userId = result[0].UserId;
+            }
+        }
+        res.json({
+            'code': resultCode,
+            'message': message,
+            'userId' : userId,
+        });
+    })
+});
\ No newline at end of file