diff --git a/app/src/main/java/io/neoterm/component/userscript/UserScriptComponent.kt b/app/src/main/java/io/neoterm/component/userscript/UserScriptComponent.kt
index a15eaa0..5cf90ba 100644
--- a/app/src/main/java/io/neoterm/component/userscript/UserScriptComponent.kt
+++ b/app/src/main/java/io/neoterm/component/userscript/UserScriptComponent.kt
@@ -13,48 +13,34 @@ import java.io.File
  * @author kiva
  */
 class UserScriptComponent : NeoComponent {
-  lateinit var userScripts: MutableList<UserScript>
+  private var userScripts = listOf<UserScript>()
+  private val scriptDir = File(NeoTermPath.USER_SCRIPT_PATH)
 
-  override fun onServiceInit() {
-    checkForFiles()
-  }
+  override fun onServiceInit() = checkForFiles()
 
   override fun onServiceDestroy() {
   }
 
-  override fun onServiceObtained() {
-    checkForFiles()
-  }
+  override fun onServiceObtained() = checkForFiles()
 
-  private fun extractDefaultScript(context: Context): Boolean {
-    try {
-      context.extractAssetsDir( "scripts", NeoTermPath.USER_SCRIPT_PATH)
-      File(NeoTermPath.USER_SCRIPT_PATH)
-        .listFiles().forEach {
-          Os.chmod(it.absolutePath, 448 /*Dec of 0700*/)
-        }
-      return true
-    } catch (e: Exception) {
-      NLog.e("UserScript", "Failed to extract default user scripts: ${e.localizedMessage}")
-      return false
+  private fun extractDefaultScript(context: Context) = kotlin.runCatching {
+    context.extractAssetsDir("scripts", NeoTermPath.USER_SCRIPT_PATH)
+    scriptDir.listFiles().forEach {
+      Os.chmod(it.absolutePath, 448 /*Dec of 0700*/)
     }
+  }.onFailure {
+    NLog.e("UserScript", "Failed to extract default user scripts: ${it.localizedMessage}")
   }
 
   private fun checkForFiles() {
-    File(NeoTermPath.USER_SCRIPT_PATH).mkdirs()
-    userScripts = mutableListOf()
-
     extractDefaultScript(App.get())
     reloadScripts()
   }
 
-  fun reloadScripts() {
-    val userScriptDir = File(NeoTermPath.USER_SCRIPT_PATH)
-    userScriptDir.mkdirs()
-
-    userScripts.clear()
-    userScriptDir.listFiles()
+  private fun reloadScripts() {
+    userScripts = scriptDir.listFiles()
       .takeWhile { it.canExecute() }
-      .mapTo(userScripts, { UserScript(it) })
+      .map { UserScript(it) }
+      .toList()
   }
-}
\ No newline at end of file
+}
diff --git a/app/src/main/java/io/neoterm/ui/pm/PackageManagerActivity.kt b/app/src/main/java/io/neoterm/ui/pm/PackageManagerActivity.kt
index aef7095..d8e7895 100644
--- a/app/src/main/java/io/neoterm/ui/pm/PackageManagerActivity.kt
+++ b/app/src/main/java/io/neoterm/ui/pm/PackageManagerActivity.kt
@@ -30,7 +30,7 @@ import java.util.*
  */
 
 class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListener, SortedListAdapter.Callback {
-  private val COMPARATOR = SortedListAdapter.ComparatorBuilder<PackageModel>()
+  private val comparator = SortedListAdapter.ComparatorBuilder<PackageModel>()
     .setOrderForModel<PackageModel>(PackageModel::class.java) { a, b ->
       a.packageInfo.packageName!!.compareTo(b.packageInfo.packageName!!)
     }
@@ -38,7 +38,7 @@ class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListen
 
   lateinit var recyclerView: androidx.recyclerview.widget.RecyclerView
   lateinit var adapter: PackageAdapter
-  lateinit var models: ArrayList<PackageModel>
+  var models = listOf<PackageModel>()
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
@@ -49,7 +49,7 @@ class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListen
 
     recyclerView = findViewById(R.id.pm_package_list)
     recyclerView.setHasFixedSize(true)
-    adapter = PackageAdapter(this, COMPARATOR, object : PackageAdapter.Listener {
+    adapter = PackageAdapter(this, comparator, object : PackageAdapter.Listener {
       override fun onModelClicked(model: PackageModel) {
         AlertDialog.Builder(this@PackageManagerActivity)
           .setTitle(model.packageInfo.packageName)
@@ -60,14 +60,11 @@ class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListen
           .setNegativeButton(android.R.string.no, null)
           .show()
       }
-
     })
     adapter.addCallback(this)
 
     recyclerView.layoutManager = LinearLayoutManager(this)
     recyclerView.adapter = adapter
-
-    models = ArrayList()
     refreshPackageList()
   }
 
@@ -174,21 +171,17 @@ class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListen
   }
 
   private fun refreshPackageList() = Thread {
-    models.clear()
     val pm = ComponentManager.getComponent<PackageComponent>()
     val sourceFiles = SourceHelper.detectSourceFiles()
 
     pm.clearPackages()
     sourceFiles.forEach { pm.reloadPackages(it, false) }
-    pm.packages.values.mapTo(models, { PackageModel(it) })
+    models = pm.packages.values.map { PackageModel(it) }.toList()
 
     this@PackageManagerActivity.runOnUiThread {
-      adapter.edit()
-        .replaceAll(models)
-        .commit()
+      adapter.edit().replaceAll(models).commit()
       if (models.isEmpty()) {
         Toast.makeText(this@PackageManagerActivity, R.string.package_list_empty, Toast.LENGTH_SHORT).show()
-        changeSource()
       }
     }
   }.start()
@@ -199,25 +192,22 @@ class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListen
   ): List<Pair<PackageModel, Int>> {
     return models
       .map {
-        Pair(
-          it,
-          StringDistance.distance(mapper(it.packageInfo).toLowerCase(Locale.ROOT), query.toLowerCase(Locale.ROOT))
-        )
+        it to StringDistance.distance(mapper(it.packageInfo).toLowerCase(Locale.ROOT), query.toLowerCase(Locale.ROOT))
       }
-      .sortedWith(Comparator { l, r -> r.second.compareTo(l.second) })
+      .sortedWith { l, r -> r.second.compareTo(l.second) }
       .toList()
   }
 
   private fun filter(models: List<PackageModel>, query: String): List<PackageModel> {
-    val filteredModelList = mutableListOf<PackageModel>()
     val prepared = models.filter {
       it.packageInfo.packageName!!.contains(query, true)
         || it.packageInfo.description!!.contains(query, true)
     }
 
-    sortDistance(prepared, query, { it.packageName!! }).mapTo(filteredModelList, { it.first })
-    sortDistance(prepared, query, { it.description!! }).mapTo(filteredModelList, { it.first })
-    return filteredModelList
+    return sortDistance(prepared, query) { it.packageName!! }
+      .plus(sortDistance(prepared, query) { it.description!! })
+      .map { it.first }
+      .toList()
   }
 
   override fun onQueryTextSubmit(text: String?) = false
@@ -235,4 +225,4 @@ class PackageManagerActivity : AppCompatActivity(), SearchView.OnQueryTextListen
     recyclerView.scrollToPosition(0)
     recyclerView.animate().alpha(1.0f)
   }
-}
\ No newline at end of file
+}
diff --git a/app/src/main/java/io/neoterm/ui/settings/GeneralSettingsActivity.kt b/app/src/main/java/io/neoterm/ui/settings/GeneralSettingsActivity.kt
index 5a33efa..37c1082 100644
--- a/app/src/main/java/io/neoterm/ui/settings/GeneralSettingsActivity.kt
+++ b/app/src/main/java/io/neoterm/ui/settings/GeneralSettingsActivity.kt
@@ -31,9 +31,7 @@ class GeneralSettingsActivity : BasePreferenceActivity() {
     }
   }
 
-  private fun postChangeShell(shellName: String) {
-    NeoPreference.setLoginShellName(shellName)
-  }
+  private fun postChangeShell(shellName: String) = NeoPreference.setLoginShellName(shellName)
 
   private fun requestInstallShell(shellName: String, currentShell: String) {
     AlertDialog.Builder(this)
diff --git a/app/src/main/java/io/neoterm/ui/setup/SetupActivity.kt b/app/src/main/java/io/neoterm/ui/setup/SetupActivity.kt
index fec5832..46babdc 100644
--- a/app/src/main/java/io/neoterm/ui/setup/SetupActivity.kt
+++ b/app/src/main/java/io/neoterm/ui/setup/SetupActivity.kt
@@ -98,8 +98,7 @@ class SetupActivity : AppCompatActivity(), View.OnClickListener, ResultListener
       when (id) {
         R.id.setup_method_backup,
         R.id.setup_method_local -> {
-          SetupHelper.makeErrorDialog(this, R.string.setup_error_parameter_null)
-            .show()
+          SetupHelper.makeErrorDialog(this, R.string.setup_error_parameter_null).show()
           return
         }
       }
diff --git a/app/src/main/java/io/neoterm/utils/utils.kt b/app/src/main/java/io/neoterm/utils/utils.kt
index 5fbc81b..68f762c 100644
--- a/app/src/main/java/io/neoterm/utils/utils.kt
+++ b/app/src/main/java/io/neoterm/utils/utils.kt
@@ -9,8 +9,8 @@ import android.provider.MediaStore
 import io.neoterm.R
 import io.neoterm.frontend.config.NeoTermPath
 import io.neoterm.frontend.floating.TerminalDialog
-import java.io.File
 import java.nio.file.Files
+import java.nio.file.Paths
 import java.text.DecimalFormat
 
 class RangedInt(private val number: Int, private val range: IntRange) {
@@ -36,14 +36,16 @@ fun Long.formatSizeInKB(): String {
   }
 }
 
-fun Context.extractAssetsDir(dirName: String, extractDir: String) {
+fun Context.extractAssetsDir(assetDir: String, extractDir: String) = kotlin.runCatching {
+  val targetDir = Paths.get(extractDir)
+  Files.createDirectories(targetDir)
   val assets = this.assets
-  assets.list(dirName)?.let {
-    it.map { File(extractDir, it) }
-      .takeWhile { !it.exists() }
-      .forEach { file ->
-        assets.open("$dirName/${file.name}").use {
-          kotlin.runCatching { Files.copy(it, file.toPath()) }
+  assets.list(assetDir)?.let {
+    it.map { targetDir.resolve(it) }
+      .takeWhile { !Files.exists(it) }
+      .forEach { targetPath ->
+        assets.open("$assetDir/${targetPath.fileName}").use {
+          Files.copy(it, targetPath)
         }
       }
   }
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 83a55ee..949f08c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -63,7 +63,7 @@
   <string name="package_details">Package: %s\nVersion: %s\nDepends: %s\nInstalled Size: %s\nDescription: %s\nHome
     Page: %s
   </string>
-  <string name="package_list_empty">Package list is empty, please check out your source.</string>
+  <string name="package_list_empty">Package list is empty, please check your source.</string>
   <string name="menu_refresh_list">Refresh</string>
   <string name="menu_update">Update and Refresh</string>
   <string name="install_font">Install Font</string>