pentaho/pentaho-kettle · error · KettleDatabaseException

Dynamic driver ' ' does not accept URL: — check the JDBC…

Error message

Dynamic driver '{effectiveClassName}' does not accept URL: {url} — check the JDBC URL format.

What it means

After acceptsURL returned false (without throwing), PDI refuses to connect and throws this error telling the developer to check the JDBC URL format. It means the driver loaded fine but explicitly does not recognize the URL scheme/shape given.

Solutions

Check that the URL's subprotocol matches the loaded driver (jdbc:<subprotocol>://...)
Verify the DatabaseMeta database type / plugin corresponds to the URL you are using
Compare against the vendor's documented URL format
If multiple drivers are installed, ensure the correct one is resolved for this connection

Example fix

// before
String url = "jdbc:mysql://host/db"; // loaded driver: postgresql
// after
String url = "jdbc:postgresql://host/db"; // matches loaded driver

Defensive patterns

Strategy: validation

Validate before calling

String sub = url.startsWith("jdbc:") && url.length() > 5 ? url.substring(5, url.indexOf(':', 5)) : null;
if (sub == null || !expectedSubprotocol.equals(sub)) throw new IllegalArgumentException("URL subprotocol '" + sub + "' does not match driver '" + expectedSubprotocol + "'");

Type guard

boolean urlMatchesDriver(String url, String subprotocol) { return url != null && url.startsWith("jdbc:" + subprotocol + ":"); }

Try / catch

try { conn = db.getConnection(); } catch (KettleDatabaseException e) { if (e.getMessage().contains("does not accept URL")) { log.error("JDBC URL format mismatch for driver: " + e.getMessage()); } else throw e; }

Prevention

Match URL subprotocol to the selected database type/plugin
Use vendor-documented URL templates
Avoid copy-pasting URLs between different database types
Check which dynamic driver got resolved for the connection

When it happens

Trigger: connectUsingClass -> openConnectionViaDynamicDriver: localDriver.acceptsURL(url) returns false — the URL prefix doesn't match the driver's expected jdbc:subprotocol format (e.g. passing a MySQL URL to a PostgreSQL driver).

Common situations: Copy-pasted URL from a different database type; missing subprotocol (jdbc://host instead of jdbc:postgresql://host); wrong database type selected in the connection dialog so the wrong driver class was loaded; typos in the subprotocol.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/6e393f76efd2b988. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/database/Database.java:952

   */
  private Connection openConnectionViaDynamicDriver( String effectiveClassName, String url, Properties properties )
    throws KettleDatabaseException {
    Driver localDriver = dynamicDriver.get();
    if ( localDriver == null ) {
      throw new KettleDatabaseException(
        "Dynamic driver for '" + effectiveClassName + "' has been unloaded (disconnect was called concurrently). "
          + "Reconnect to reload the driver." );
    }
    boolean accepts;
    try {
      accepts = localDriver.acceptsURL( url );
    } catch ( Exception e ) {
      throw new KettleDatabaseException(
        "Dynamic driver '" + effectiveClassName + "' threw exception checking URL '"
          + url + "': " + errorMsg( e ), e );
    }
    if ( !accepts ) {
      throw new KettleDatabaseException(
        "Dynamic driver '" + effectiveClassName + "' does not accept URL: " + url
          + " — check the JDBC URL format." );
    }
    try {
      Connection c = localDriver.connect( url, properties );
      if ( c == null ) {
        throw new KettleDatabaseException(
          "Dynamic driver '" + effectiveClassName + "' returned null for URL: " + url
            + " — check that the URL format and driver class are correct." );
      }
      return c;
    } catch ( KettleDatabaseException e ) {
      throw e;
    } catch ( Exception e ) {
      throw new KettleDatabaseException(
        "Dynamic driver '" + effectiveClassName + "' failed to connect to URL '"
          + url + "': " + errorMsg( e ), e );
    }

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