apache/seatunnel · warning

Failed to load JDBC driver {}

Error message

Failed to load JDBC driver {}

What it means

StarRocksSink's constructor tries to preload the MySQL Connector/J driver (com.mysql.cj.jdbc.Driver) into DriverManager for JDBC-based save-mode operations. If the class is missing or fails to initialize, this warning is logged and construction continues; later JDBC operations may fail with 'No suitable driver'.

Source

Thrown at seatunnel-connectors-v2/connector-starrocks/src/main/java/org/apache/seatunnel/connectors/seatunnel/starrocks/sink/StarRocksSink.java:70

    private final SinkConfig sinkConfig;
    private final DataSaveMode dataSaveMode;
    private final SchemaSaveMode schemaSaveMode;
    private final CatalogTable catalogTable;
    private final Map<String, String> tableOptions;

    public StarRocksSink(
            SinkConfig sinkConfig, CatalogTable catalogTable, Map<String, String> tableOptions) {
        this.sinkConfig = sinkConfig;
        this.tableSchema = catalogTable.getTableSchema();
        this.catalogTable = catalogTable;
        this.tableOptions = tableOptions;
        this.dataSaveMode = sinkConfig.getDataSaveMode();
        this.schemaSaveMode = sinkConfig.getSchemaSaveMode();
        // Load the JDBC driver in to DriverManager
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (Exception e) {
            log.warn("Failed to load JDBC driver {}", "com.mysql.cj.jdbc.Driver", e);
        }
    }

    @Override
    public String getPluginName() {
        return StarRocksCatalogFactory.IDENTIFIER;
    }

    @Override
    public StarRocksSinkWriter createWriter(SinkWriter.Context context) {
        // Load the JDBC driver in to DriverManager
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (Exception e) {
            log.warn("Failed to load JDBC driver {}", "com.mysql.cj.jdbc.Driver", e);
        }
        TablePath sinkTablePath = catalogTable.getTablePath();
        return new StarRocksSinkWriter(context, sinkConfig, tableSchema, sinkTablePath);

View on GitHub (pinned to cf67b549a7)

Solutions

1. Download mysql-connector-java-8.x (mysql-connector-j) into $SEATUNNEL_HOME/plugins/<connector>/lib or connectors dir and retry
2. Verify the jar contains com/mysql/cj/jdbc/Driver.class (unzip -l)
3. If schema save modes are unused and stream load only is needed, the warning can be ignored, but JDBC save-mode handlers will fail later

try {
  Class.forName("com.mysql.cj.jdbc.Driver");
} catch (ClassNotFoundException e) {
  throw new IllegalStateException("mysql-connector-j 8.x jar missing from plugin classpath", e);
}

When it happens

Trigger: Instantiating StarRocksSink when the mysql-connector-java jar is not on the classpath or the driver class fails static initialization (incompatible java.sql/ServiceLoader environment).

Common situations: Missing connector jar in the plugin directory (install-plugin.sh not run or jar excluded); shaded/fat-jar conflicts; using a Driver 5.x (com.mysql.jdbc.Driver) instead of 8.x.

Related errors

• Failed to load JDBC driver com.mysql.cj.jdbc.Driver
• Failed to load JDBC driver com.mysql.cj.jdbc.Driver
• DRIVER_NOT_FOUND
• CONNECT_FAILED
• CLASS_NOT_FOUND

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/1d8778ad67e10ecc. Report an issue: GitHub.