🆙 Make Emulator Full MariaDB

- Swap mysql-connector-j → mariadb-java-client in pom.xml
- Changed JDBC URL to jdbc:mariadb://
Add all the HikariCP properties above (configurable via config.ini with sensible defaults)
- Fix the double-close in Database.dispose()

Emulator/pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.eu.habbo</groupId>
     <artifactId>Habbo</artifactId>
-    <version>4.1.0</version>
+    <version>4.0.5</version>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -86,11 +86,11 @@
             <version>2.11.0</version>
         </dependency>
 
-        <!-- MySQL Connector -->
+        <!-- MariaDB Connector/J (native driver for MariaDB) -->
         <dependency>
-            <groupId>com.mysql</groupId>
+            <groupId>org.mariadb.jdbc</groupId>
-            <artifactId>mysql-connector-j</artifactId>
+            <artifactId>mariadb-java-client</artifactId>
-            <version>9.1.0</version>
+            <version>3.5.1</version>
             <scope>runtime</scope>
         </dependency>
 

Emulator/src/main/java/com/eu/habbo/database/Database.java

@@ -48,11 +48,11 @@ public class Database {
     }
 
     public void dispose() {
-        if (this.databasePool != null) {
+        // dataSource is the same instance returned by databasePool.getDatabase(),
-            this.databasePool.getDatabase().close();
+        // so close it exactly once.
+        if (this.dataSource != null && !this.dataSource.isClosed()) {
+            this.dataSource.close();
         }
-
-        this.dataSource.close();
     }
 
     public HikariDataSource getDataSource() {

Emulator/src/main/java/com/eu/habbo/database/DatabasePool.java

@@ -8,41 +8,85 @@ import org.slf4j.LoggerFactory;
 
 class DatabasePool {
     private final Logger log = LoggerFactory.getLogger(DatabasePool.class);
+
+    // Connection settings
+    private static final String DB_HOSTNAME_KEY = "db.hostname";
+    private static final String DB_PORT_KEY     = "db.port";
+    private static final String DB_PASSWORD_KEY = "db.password";
+    private static final String DB_NAME_KEY     = "db.database";
+    private static final String DB_USER_KEY     = "db.username";
+    private static final String DB_PARAMS_KEY   = "db.params";
+
+    // Pool sizing
     private static final String DB_POOL_MAX_SIZE = "db.pool.maxsize";
     private static final String DB_POOL_MIN_SIZE = "db.pool.minsize";
-    private static final String DB_HOSTNAME_KEY = "db.hostname";
+
-    private static final String DB_PORT_KEY = "db.port";
+    // Pool tuning (all overridable via config.ini; sensible MariaDB defaults apply otherwise)
-    private static final String DB_PASSWORD_KEY = "db.password";
+    private static final String DB_POOL_CONNECTION_TIMEOUT  = "db.pool.connection_timeout_ms";
-    private static final String DB_NAME_KEY = "db.database";
+    private static final String DB_POOL_IDLE_TIMEOUT        = "db.pool.idle_timeout_ms";
-    private static final String DB_USER_KEY = "db.username";
+    private static final String DB_POOL_MAX_LIFETIME        = "db.pool.max_lifetime_ms";
-    private static final String DB_PARAMS_KEY = "db.params";
+    private static final String DB_POOL_LEAK_THRESHOLD      = "db.pool.leak_detection_ms";
+    private static final String DB_POOL_VALIDATION_TIMEOUT  = "db.pool.validation_timeout_ms";
+
     private HikariDataSource database;
-    private static DatabasePool instance;
 
     DatabasePool() {
     }
 
-    public static synchronized DatabasePool getInstance() {
-        if (instance == null) {
-            instance = new DatabasePool();
-        }
-        return instance;
-    }
-
     public boolean getStoragePooling(ConfigurationManager config) {
         try {
             HikariConfig databaseConfiguration = new HikariConfig();
+
+            // Pool sizing
             databaseConfiguration.setMaximumPoolSize(config.getInt(DB_POOL_MAX_SIZE, 50));
             databaseConfiguration.setMinimumIdle(config.getInt(DB_POOL_MIN_SIZE, 10));
-            databaseConfiguration.setJdbcUrl("jdbc:mysql://" + config.getValue(DB_HOSTNAME_KEY, "localhost") + ":" + config.getValue(DB_PORT_KEY, "3306") + "/" + config.getValue(DB_NAME_KEY) + config.getValue(DB_PARAMS_KEY));
+
-            databaseConfiguration.addDataSourceProperty("serverName", config.getValue(DB_HOSTNAME_KEY, "localhost"));
+            // Pool timeouts (milliseconds)
-            databaseConfiguration.addDataSourceProperty("port", config.getValue(DB_PORT_KEY, "3306"));
+            databaseConfiguration.setConnectionTimeout(config.getInt(DB_POOL_CONNECTION_TIMEOUT, 10_000));
-            databaseConfiguration.addDataSourceProperty("databaseName", config.getValue(DB_NAME_KEY));
+            databaseConfiguration.setIdleTimeout(config.getInt(DB_POOL_IDLE_TIMEOUT, 600_000));
-            databaseConfiguration.addDataSourceProperty("user", config.getValue(DB_USER_KEY));
+            databaseConfiguration.setMaxLifetime(config.getInt(DB_POOL_MAX_LIFETIME, 1_800_000));
-            databaseConfiguration.addDataSourceProperty("password", config.getValue(DB_PASSWORD_KEY));
+            databaseConfiguration.setValidationTimeout(config.getInt(DB_POOL_VALIDATION_TIMEOUT, 5_000));
+
+            // Leak detection: 0 disables it. Default 20s helps locate connections
+            // that weren't closed in a try-with-resources block.
+            int leakThreshold = config.getInt(DB_POOL_LEAK_THRESHOLD, 20_000);
+            if (leakThreshold > 0) {
+                databaseConfiguration.setLeakDetectionThreshold(leakThreshold);
+            }
+
+            // Use the MariaDB Connector/J native protocol instead of the Oracle MySQL driver.
+            databaseConfiguration.setJdbcUrl("jdbc:mariadb://"
+                    + config.getValue(DB_HOSTNAME_KEY, "localhost") + ":"
+                    + config.getValue(DB_PORT_KEY, "3306") + "/"
+                    + config.getValue(DB_NAME_KEY)
+                    + config.getValue(DB_PARAMS_KEY));
+            databaseConfiguration.setUsername(config.getValue(DB_USER_KEY));
+            databaseConfiguration.setPassword(config.getValue(DB_PASSWORD_KEY));
+
+            // Prepared-statement caching. Without these, Hikari's cache is off entirely
+            // and every prepareStatement() call re-parses on the server side.
+            databaseConfiguration.addDataSourceProperty("cachePrepStmts",          "true");
+            databaseConfiguration.addDataSourceProperty("prepStmtCacheSize",       "500");
+            databaseConfiguration.addDataSourceProperty("prepStmtCacheSqlLimit",   "2048");
+            databaseConfiguration.addDataSourceProperty("useServerPrepStmts",      "true");
+
+            // Bulk write throughput: rewrites batched INSERTs into a single multi-value
+            // INSERT statement. Huge win for item/room/inventory persistence paths.
+            databaseConfiguration.addDataSourceProperty("rewriteBatchedStatements", "true");
+
+            // Cut per-connection round-trips.
+            databaseConfiguration.addDataSourceProperty("cacheServerConfiguration", "true");
+            databaseConfiguration.addDataSourceProperty("useLocalSessionState",     "true");
+            databaseConfiguration.addDataSourceProperty("cacheResultSetMetadata",   "true");
+            databaseConfiguration.addDataSourceProperty("elideSetAutoCommits",      "true");
+            databaseConfiguration.addDataSourceProperty("maintainTimeStats",        "false");
+
+            databaseConfiguration.setPoolName("HabboHikariPool");
+
             log.info("INITIALIZING DATABASE SERVER: " + config.getValue(DB_HOSTNAME_KEY));
             log.info("ON PORT: " + config.getValue(DB_PORT_KEY));
             log.info("HABBO DATABASE: " + config.getValue(DB_NAME_KEY));
+            log.info("USING DRIVER: MariaDB Connector/J");
 
             this.database = new HikariDataSource(databaseConfiguration);
         } catch (Exception e) {
@@ -58,4 +102,4 @@ class DatabasePool {
         }
         return database;
     }
-}
+}