Refactoring

app/src/main/java/eu/faircode/email/DB.java

@@ -32,6 +32,8 @@ import org.json.JSONObject;
 import java.io.File;
 import java.lang.reflect.Field;
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.Date;
 import java.util.List;
 import java.util.Map;
@@ -129,14 +131,14 @@ public abstract class DB extends RoomDatabase {
     private static final String[] DB_TABLES = new String[]{
             "identity", "account", "folder", "message", "attachment", "operation", "contact", "certificate", "answer", "rule", "search", "log"};
 
-    private static final String[] DB_PRAGMAS = new String[]{
+    private static final List<String> DB_PRAGMAS = Collections.unmodifiableList(Arrays.asList(
             "synchronous", "journal_mode",
             "wal_checkpoint", "wal_autocheckpoint", "journal_size_limit",
             "page_count", "page_size", "max_page_count", "freelist_count",
             "cache_size", "cache_spill",
             "soft_heap_limit", "hard_heap_limit", "mmap_size",
             "foreign_keys"
-    };
+    ));
 
     @Override
     public void init(@NonNull DatabaseConfiguration configuration) {