diff --git a/data/src/main/java/one/nem/lacerta/source/db/impl/placeholder b/data/src/main/java/one/nem/lacerta/source/db/impl/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/db/model/placeholder b/data/src/main/java/one/nem/lacerta/source/db/model/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/db/module/placeholder b/data/src/main/java/one/nem/lacerta/source/db/module/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/db/repository/placeholder b/data/src/main/java/one/nem/lacerta/source/db/repository/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/impl/CommonImpl.java b/data/src/main/java/one/nem/lacerta/source/pref/impl/CommonImpl.java
deleted file mode 100644
index 49cd07d0..00000000
--- a/data/src/main/java/one/nem/lacerta/source/pref/impl/CommonImpl.java
+++ /dev/null
@@ -1,60 +0,0 @@
-package one.nem.lacerta.source.pref.impl;
-
-import android.content.Context;
-import android.content.SharedPreferences;
-
-import androidx.appcompat.app.AppCompatActivity;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.stream.Collectors;
-
-import javax.inject.Inject;
-
-import dagger.hilt.android.AndroidEntryPoint;
-import dagger.hilt.android.qualifiers.ApplicationContext;
-
-import one.nem.lacerta.source.pref.repository.Common;
-
-public class CommonImpl implements Common {
-
-    Context applicationContext;
-
-    @Inject
-    public CommonImpl(@ApplicationContext Context applicationContext) {
-        this.applicationContext = applicationContext;
-    }
-
-    public String getStringValue(String key) {
-        SharedPreferences pref = applicationContext.getSharedPreferences("common", Context.MODE_PRIVATE);
-        return pref.getString(key, "");
-    }
-
-    public void setStringValue(String key, String value) {
-        SharedPreferences pref = applicationContext.getSharedPreferences("common", Context.MODE_PRIVATE);
-        SharedPreferences.Editor editor = pref.edit();
-        editor.putString(key, value);
-        editor.apply();
-    }
-
-    public boolean isExist(String key) {
-        SharedPreferences pref = applicationContext.getSharedPreferences("common", Context.MODE_PRIVATE);
-        return pref.contains(key);
-    }
-
-    public void remove(String key) {
-        SharedPreferences pref = applicationContext.getSharedPreferences("common", Context.MODE_PRIVATE);
-        SharedPreferences.Editor editor = pref.edit();
-        editor.remove(key);
-        editor.apply();
-    }
-
-    public ArrayList<String> getExistKeys() {
-        SharedPreferences pref = applicationContext.getSharedPreferences("common", Context.MODE_PRIVATE);
-        // キーだけをArrayListに切り出す
-        return new ArrayList<>(pref.getAll().keySet());
-    }
-
-
-
-}
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/impl/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/impl/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/model/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/model/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/module/CommonModule.java b/data/src/main/java/one/nem/lacerta/source/pref/module/CommonModule.java
deleted file mode 100644
index 1e5a8579..00000000
--- a/data/src/main/java/one/nem/lacerta/source/pref/module/CommonModule.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package one.nem.lacerta.source.pref.module;
-
-import dagger.Binds;
-import dagger.Module;
-import dagger.hilt.InstallIn;
-import dagger.hilt.components.SingletonComponent;
-import one.nem.lacerta.source.pref.impl.CommonImpl;
-import one.nem.lacerta.source.pref.repository.Common;
-
-@Module
-@InstallIn(SingletonComponent.class)
-abstract public class CommonModule {
-
-    @Binds
-    public abstract Common bindCommon(CommonImpl commonImpl);
-}
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/module/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/module/placeholder
deleted file mode 100644
index e69de29b..00000000
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/repository/Common.java b/data/src/main/java/one/nem/lacerta/source/pref/repository/Common.java
deleted file mode 100644
index dec372d0..00000000
--- a/data/src/main/java/one/nem/lacerta/source/pref/repository/Common.java
+++ /dev/null
@@ -1,18 +0,0 @@
-package one.nem.lacerta.source.pref.repository;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public interface Common {
-    // さまざまな用途で使うPref
-
-    String getStringValue(String key);
-
-    void setStringValue(String key, String value);
-
-    boolean isExist(String key);
-
-    void remove(String key);
-
-    ArrayList<String> getExistKeys();
-}
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/repository/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/repository/placeholder
deleted file mode 100644
index e69de29b..00000000