hibernate/hibernate-orm · critical · StrategySelectionException

Could not instantiate named dialect class [%s]

Error message

Could not instantiate named dialect class [%s]

What it means

DialectFactoryImpl.buildDialectInstance located the class named by hibernate.dialect via the strategy selector, but reflective construction failed with InstantiationException (abstract class or no usable constructor), IllegalAccessException (non-public constructor), or InvocationTargetException (constructor itself threw). The original exception is carried as the cause of StrategySelectionException.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/engine/jdbc/dialect/internal/DialectFactoryImpl.java:142

					Dialect.class,
					dialectReference,
					(Dialect) null,
					(dialectClass) -> {
						try {
							try {
								if ( resolutionInfoSource != null ) {
									return dialectClass.getConstructor( DialectResolutionInfo.class ).newInstance(
											resolutionInfoSource.getDialectResolutionInfo()
									);
								}
							}
							catch (NoSuchMethodException nsme) {

							}
							return dialectClass.newInstance();
						}
						catch (InstantiationException | IllegalAccessException | InvocationTargetException e) {
							throw new StrategySelectionException(
									String.format( "Could not instantiate named dialect class [%s]", dialectClass.getName() ),
									e
							);
						}
					}
			);
			if ( dialect == null ) {
				throw new HibernateException( "Unable to construct requested dialect [" + dialectReference + "]" );
			}
			else if ( Dialect.class.getPackage() == dialect.getClass().getPackage() ) {
				DEPRECATION_LOGGER.automaticDialect( dialect.getClass().getSimpleName() );
			}
			return dialect;
		}
		catch (StrategySelectionException e) {
			final String dialectFqn = dialectReference.toString();
			if ( LEGACY_DIALECTS.contains( dialectFqn ) ) {
				throw new StrategySelectionException(

View on GitHub (pinned to fad1729dce)

Solutions

  1. Ensure the dialect class is concrete with a public no-arg constructor (or a public constructor accepting DialectResolutionInfo)
  2. Read the nested cause: InvocationTargetException.getTargetException() shows the real constructor error
  3. If using a custom subclass, expose `public MyDialect() { super(); }`
  4. Prefer a supported built-in dialect FQN unless customization is required

Example fix

// before
public abstract class MyDialect extends PostgreSQLDialect {} // abstract -> InstantiationException

// after
public class MyDialect extends PostgreSQLDialect {
    public MyDialect() {
        super(DatabaseVersion.make(15, 2));
    }
}
Defensive patterns

Strategy: validation

Validate before calling

// validate the configured dialect class before bootstrap
Class<?> c = Class.forName(dialectClassName, false, getClass().getClassLoader());
int mods = c.getModifiers();
if ( Modifier.isAbstract(mods) || !Modifier.isPublic(mods)
        || !Modifier.isPublic(c.getConstructor().getModifiers()) ) {
    throw new ConfigurationException("Dialect class must be public, concrete, with a public no-arg ctor: " + dialectClassName);
}

Try / catch

try {
    return builder.build();
} catch (StrategySelectionException e) {
    Throwable root = e.getCause() instanceof InvocationTargetException ite ? ite.getTargetException() : e.getCause();
    log.error("Dialect constructor failed: {}", root, e);
    throw e;
}

Prevention

When it happens

Trigger: hibernate.dialect names a class that is abstract, lacks both a public no-arg constructor and a DialectResolutionInfo-taking constructor, has package-private constructors, or whose constructor throws (e.g. it rejects the database version it detects).

Common situations: Custom dialect subclasses with only a Dialect(DialectResolutionInfo) constructor that is not public; pointing hibernate.dialect at an interface or abstract base; a third-party dialect whose constructor fails on the detected metadata; constructor visibility changed by module/JPMS restrictions.

Related errors

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/1875a2511c85ceb6. Report an issue: GitHub.