diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index d291b3d..169fd0d 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -3,11 +3,14 @@
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
-        <compositeConfiguration>
-          <compositeBuild compositeDefinitionSource="SCRIPT" />
-        </compositeConfiguration>
         <option name="distributionType" value="DEFAULT_WRAPPED" />
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+            <option value="$PROJECT_DIR$/app" />
+          </set>
+        </option>
         <option name="resolveModulePerSourceSet" value="false" />
         <option name="testRunner" value="PLATFORM" />
       </GradleProjectSettings>
diff --git a/README.md b/README.md
index 9ab0a5d..4cff9b5 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,9 @@ Simple Hello, [input]! app
 1. Add an OnClick listener to btnSubmit
 2. Inside the OnClick listener, get the EditText (etName) value
 3. Set the TextView (tvHello) value to the EditText's value
+
+# Problems and Solutions
+master = java: https://github.com/git-mad/HelloInput/tree/master
+java_solution: https://github.com/git-mad/HelloInput/tree/java_solution
+kotlin: https://github.com/git-mad/HelloInput/tree/kotlin
+kotlin_solution: https://github.com/git-mad/HelloInput/tree/kotlin_solution
diff --git a/app/build.gradle b/app/build.gradle
index 9a4add4..7c38828 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,4 +1,6 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-android'
 
 android {
     compileSdkVersion 28
@@ -21,10 +23,14 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'androidx.appcompat:appcompat:1.0.2'
+    implementation "androidx.core:core-ktx:1.1.0"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
 
     testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'androidx.test:runner:1.1.1'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
+    androidTestImplementation 'androidx.test:runner:1.2.0'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0' }
+repositories {
+    mavenCentral()
 }
diff --git a/app/src/main/java/club/gitmad/helloinput/MainActivity.java b/app/src/main/java/club/gitmad/helloinput/MainActivity.java
deleted file mode 100644
index b38585e..0000000
--- a/app/src/main/java/club/gitmad/helloinput/MainActivity.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package club.gitmad.helloinput;
-
-import androidx.appcompat.app.AppCompatActivity;
-
-import android.os.Bundle;
-import android.util.Log;
-import android.view.View;
-import android.widget.EditText;
-import android.widget.TextView;
-
-public class MainActivity extends AppCompatActivity {
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        setContentView(R.layout.activity_main);
-
-        // TODO: Set a listener for btnSubmit. Inside the listener, get the value in etName and set it to tvHello
-    }
-}
diff --git a/app/src/main/java/club/gitmad/helloinput/MainActivity.kt b/app/src/main/java/club/gitmad/helloinput/MainActivity.kt
new file mode 100644
index 0000000..cc6c8dc
--- /dev/null
+++ b/app/src/main/java/club/gitmad/helloinput/MainActivity.kt
@@ -0,0 +1,17 @@
+package club.gitmad.helloinput
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import kotlinx.android.synthetic.main.activity_main.*
+
+class MainActivity : AppCompatActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+
+        btnSubmit.setOnClickListener {
+            val name = etName.text.toString()
+            tvHello.text = "Hello, $name!"
+        }
+    }
+}
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index a5bb815..e506ebe 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,6 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
+    ext.kotlin_version = '1.3.61'
     repositories {
         google()
         jcenter()
@@ -8,7 +9,8 @@ buildscript {
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:3.5.3'
-        
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }