diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmInstanceWrapper.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmInstanceWrapper.kt
index 851605437f..4d02d696d8 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmInstanceWrapper.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmInstanceWrapper.kt
@@ -19,7 +19,7 @@ package org.matrix.android.sdk.internal.database
 import io.realm.Realm
 import java.io.Closeable
 
-class RealmInstanceWrapper(private val realm: Realm, private val closeRealmOnClose: Boolean) : Closeable {
+internal class RealmInstanceWrapper (private val realm: Realm, private val closeRealmOnClose: Boolean) : Closeable {
 
     override fun close() {
         if (closeRealmOnClose) {
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmSessionProvider.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmSessionProvider.kt
index a232d83b6d..a7f934ffc0 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmSessionProvider.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/database/RealmSessionProvider.kt
@@ -31,7 +31,7 @@ import kotlin.concurrent.getOrSet
  * instance. This does check each time if you are on the main thread or not and returns the appropriate realm instance.
  */
 @SessionScope
-class RealmSessionProvider @Inject constructor(@SessionDatabase private val monarchy: Monarchy)
+internal class RealmSessionProvider @Inject constructor(@SessionDatabase private val monarchy: Monarchy)
     : SessionLifecycleObserver {
 
     private val realmThreadLocal = ThreadLocal<Realm>()
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/SessionModule.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/SessionModule.kt
index e2042bfeac..5397b8d9bd 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/SessionModule.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/SessionModule.kt
@@ -326,27 +326,27 @@ internal abstract class SessionModule {
 
     @Binds
     @IntoSet
-    abstract fun bindIntegrationManager(observer: IntegrationManager): SessionLifecycleObserver
+    abstract fun bindIntegrationManager(manager: IntegrationManager): SessionLifecycleObserver
 
     @Binds
     @IntoSet
-    abstract fun bindWidgetUrlFormatter(observer: DefaultWidgetURLFormatter): SessionLifecycleObserver
+    abstract fun bindWidgetUrlFormatter(formatter: DefaultWidgetURLFormatter): SessionLifecycleObserver
 
     @Binds
     @IntoSet
-    abstract fun bindShieldTrustUpdated(observer: ShieldTrustUpdater): SessionLifecycleObserver
+    abstract fun bindShieldTrustUpdated(updater: ShieldTrustUpdater): SessionLifecycleObserver
 
     @Binds
     @IntoSet
-    abstract fun bindIdentityService(observer: DefaultIdentityService): SessionLifecycleObserver
+    abstract fun bindIdentityService(service: DefaultIdentityService): SessionLifecycleObserver
 
     @Binds
     @IntoSet
-    abstract fun bindDatabaseCleaner(observer: DatabaseCleaner): SessionLifecycleObserver
+    abstract fun bindDatabaseCleaner(cleaner: DatabaseCleaner): SessionLifecycleObserver
 
     @Binds
     @IntoSet
-    abstract fun bindRealmSessionProvider(observer: RealmSessionProvider): SessionLifecycleObserver
+    abstract fun bindRealmSessionProvider(provider: RealmSessionProvider): SessionLifecycleObserver
 
     @Binds
     abstract fun bindInitialSyncProgressService(service: DefaultInitialSyncProgressService): InitialSyncProgressService
diff --git a/tools/check/forbidden_strings_in_code.txt b/tools/check/forbidden_strings_in_code.txt
index b5438a0c5b..425fc5a6d6 100644
--- a/tools/check/forbidden_strings_in_code.txt
+++ b/tools/check/forbidden_strings_in_code.txt
@@ -172,3 +172,6 @@ import org.matrix.androidsdk.crypto.data===2
 
 ### Use `Context#getSystemService` extension function provided by `core-ktx`
 getSystemService\(Context
+
+### Use DefaultSharedPreferences.getInstance() instead for better performance
+PreferenceManager\.getDefaultSharedPreferences==2