diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 609e114..ec87427 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -20,11 +20,6 @@
             <meta-data
                 android:name="android.app.lib_name"
                 android:value="" />
-            <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
         </activity>
         <activity
             android:name=".coroutines.learning2.CoroutineLearning2Activity"
@@ -37,10 +32,10 @@
             android:name=".MainActivity"
             android:exported="true">
 
-            <!-- <intent-filter> -->
-            <!-- <action android:name="android.intent.action.MAIN" />&ndash;&gt; -->
-            <!-- <category android:name="android.intent.category.LAUNCHER" />&ndash;&gt; -->
-            <!-- </intent-filter> -->
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
 
             <meta-data
                 android:name="android.app.lib_name"
diff --git a/app/src/main/java/com/example/androidconcepts/MainActivity.kt b/app/src/main/java/com/example/androidconcepts/MainActivity.kt
index 3ec2aa2..ab48b5d 100644
--- a/app/src/main/java/com/example/androidconcepts/MainActivity.kt
+++ b/app/src/main/java/com/example/androidconcepts/MainActivity.kt
@@ -4,6 +4,7 @@ import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import android.widget.Toast
 import com.example.androidconcepts.common.UiThreadPoster
+import com.example.androidconcepts.fileStorage.learning1.FileLearning1
 import kotlinx.coroutines.*
 
 class MainActivity : AppCompatActivity() {
@@ -12,32 +13,6 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
-        // TODO : move to coroutines package
-        CoroutineScope(Job() + Dispatchers.Main.immediate).launch {
-            suspend {   // doesn't block ui
-                performWhileTrueLoop()
-            }
-
-            performWhileTrueLoop() // blocks ui
-        }
-    }
-
-    private suspend fun showToastEvery3Sec() {
-        while (true) {
-            delay(3 * 1000)
-            UiThreadPoster().post {
-                Toast.makeText(this.applicationContext, "yeah", Toast.LENGTH_SHORT).show()
-            }
-        }
-    }
-
-    private suspend fun suspendWrapper() {
-        performWhileTrueLoop()
-    }
-
-    private suspend fun performWhileTrueLoop() = withContext(Dispatchers.Main.immediate){
-        while (true) {
-
-        }
+        FileLearning1(this).start()
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/androidconcepts/dataTypes/bytes/ByteLearning1.kt b/app/src/main/java/com/example/androidconcepts/dataTypes/bytes/ByteLearning1.kt
new file mode 100644
index 0000000..0bc259f
--- /dev/null
+++ b/app/src/main/java/com/example/androidconcepts/dataTypes/bytes/ByteLearning1.kt
@@ -0,0 +1,19 @@
+package com.example.androidconcepts.dataTypes.bytes
+
+class ByteLearning1 {
+
+    fun execute(): ByteArray {
+        val data: Byte = 127 // 128 gives error
+
+        val alphabets = "abcdefghijklmnopqrstuvwxyz"
+
+//      for manually creating ByteArray...
+
+//        val bArr = ByteArray(26)
+//        alphabets.forEachIndexed { i, ch ->
+//            bArr[i] = ch.code.toByte()
+//        }
+
+        return alphabets.toByteArray()
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/androidconcepts/fileStorage/learning1/FileLearning1.kt b/app/src/main/java/com/example/androidconcepts/fileStorage/learning1/FileLearning1.kt
new file mode 100644
index 0000000..4bb8d8b
--- /dev/null
+++ b/app/src/main/java/com/example/androidconcepts/fileStorage/learning1/FileLearning1.kt
@@ -0,0 +1,108 @@
+package com.example.androidconcepts.fileStorage.learning1
+
+import android.content.Context
+import android.content.Context.MODE_PRIVATE
+import android.util.Log
+import androidx.core.text.isDigitsOnly
+import java.io.File
+
+class FileLearning1 constructor(private val context: Context) {
+
+    private val myDigitsFileName = "myCreatedFile"
+
+    fun start() {
+        logBasicDetails()
+
+        Log.d("FILE","-------------------------")
+
+        incrementAppLaunchCounterInFile()
+    }
+
+    private fun incrementAppLaunchCounterInFile() {
+        checkIfFileExistsElseCreate()
+
+        Log.d("FILE","-------------------------")
+
+        var readData = readAndGetDataFromFile(myDigitsFileName)
+
+        if (!readData.isDigitsOnly())
+            readData = "0"
+
+        val newCount = readData.toInt() + 1
+
+        writeNewDataToFile(newCount)
+
+        Log.d("FILE", "data : $readData")
+    }
+
+    private fun checkIfFileExistsElseCreate() {
+        // though in input/output stream we directly pass the name to access from filesDir,
+        // here we need to explicitly mention the path.
+        val file = File(context.filesDir.path + File.separator + myDigitsFileName)
+
+        if (!file.exists()) {
+            Log.d("FILE", "created new file path : " + file.path)
+        } else {
+            Log.d("FILE", "already exists : " + file.path)
+        }
+    }
+
+    private fun readAndGetDataFromFile(filesDirName: String): String {
+        var readData = ""
+
+        // any file accessed like this (by passing direct name) will be accessed from files directory of the app.
+        context.openFileInput(filesDirName)
+            .use {
+                while (true) {
+                    val data = it.read()
+                    if (data == -1) break
+                    readData += data.toChar().toString()
+                }
+            }
+
+        return readData
+    }
+
+    private fun writeNewDataToFile(newCount: Int) {
+        // any file accessed like this (by passing direct name) will be accessed from files directory of the app.
+        context.openFileOutput(myDigitsFileName, MODE_PRIVATE).use {
+            it.write(newCount.toString().toByteArray())
+        }
+    }
+
+    private fun logBasicDetails() {
+
+        context.fileList().forEach {
+            val file = File(context.filesDir.path + File.separator + it)
+            Log.d("FILE", "file details : " + file.path)
+        }
+
+        Log.d("FILE","-------------------------")
+
+        printDetails(
+            prefix = "cacheDir",
+            file = context.cacheDir
+        ) // cacheDir path /data/user/0/com.example.androidconcepts/cache name : cache isDir : true
+
+        printDetails(
+            prefix = "filesDir",
+            file = context.filesDir
+        ) // filesDir path /data/user/0/com.example.androidconcepts/files name : files isDir : true
+
+        if (context.externalCacheDir != null)
+            printDetails(
+                prefix = "externalDir",
+                file = context.externalCacheDir!!
+            ) // externalDir path /storage/emulated/0/Android/data/com.example.androidconcepts/cache name : cache isDir : true
+    }
+
+    private fun printDetails(prefix: String, file: File): String {
+        val string =
+            "$prefix path " + file.path + " name : " + file.name + " isDir : " + file.isDirectory
+
+        Log.d("FILE", string)
+
+        return string
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/test/java/com/example/androidconcepts/dataTypes/bytes/ByteLearning1Test.kt b/app/src/test/java/com/example/androidconcepts/dataTypes/bytes/ByteLearning1Test.kt
new file mode 100644
index 0000000..3f5ded4
--- /dev/null
+++ b/app/src/test/java/com/example/androidconcepts/dataTypes/bytes/ByteLearning1Test.kt
@@ -0,0 +1,55 @@
+package com.example.androidconcepts.dataTypes.bytes
+
+import org.junit.Before
+import org.junit.Test
+
+class ByteLearning1Test {
+
+    private lateinit var SUT: ByteLearning1
+
+    @Test
+    fun simpleTest() {
+
+        val result = SUT.execute()
+
+        result.forEachIndexed { i, ch ->
+            println("BYTE DEBUG : " + ('a' + i) + " " + ch)
+        }
+
+        /**
+         *
+        BYTE DEBUG : a 97
+        BYTE DEBUG : b 98
+        BYTE DEBUG : c 99
+        BYTE DEBUG : d 100
+        BYTE DEBUG : e 101
+        BYTE DEBUG : f 102
+        BYTE DEBUG : g 103
+        BYTE DEBUG : h 104
+        BYTE DEBUG : i 105
+        BYTE DEBUG : j 106
+        BYTE DEBUG : k 107
+        BYTE DEBUG : l 108
+        BYTE DEBUG : m 109
+        BYTE DEBUG : n 110
+        BYTE DEBUG : o 111
+        BYTE DEBUG : p 112
+        BYTE DEBUG : q 113
+        BYTE DEBUG : r 114
+        BYTE DEBUG : s 115
+        BYTE DEBUG : t 116
+        BYTE DEBUG : u 117
+        BYTE DEBUG : v 118
+        BYTE DEBUG : w 119
+        BYTE DEBUG : x 120
+        BYTE DEBUG : y 121
+        BYTE DEBUG : z 122
+         */
+    }
+
+    @Before
+    fun setup() {
+        SUT = ByteLearning1()
+    }
+
+}
\ No newline at end of file