hibernate/hibernate-orm · error · ConnectionProviderConfigurationException

Unknown transaction isolation level: {}

Error message

Unknown transaction isolation level: {}

What it means

Error "Unknown transaction isolation level: {}" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/ConnectionProviderInitiator.java:363

				return ISOLATION_VALUE_MAP.get( string );
			}
			else {
				// it could be a String representation of the isolation numeric value
				try {
					final int isolationLevel = parseInt( string );
					checkIsolationLevel( isolationLevel );
					return isolationLevel;
				}
				catch (NumberFormatException ignore) {
					throw new ConnectionProviderConfigurationException( "Unknown transaction isolation level: '" + string + "'" );
				}
			}
		}
	}

	private static void checkIsolationLevel(int isolationLevel) {
		if ( !ISOLATION_VALUE_CONSTANT_NAME_MAP.containsKey( isolationLevel ) ) {
			throw new ConnectionProviderConfigurationException( "Unknown transaction isolation level: " + isolationLevel );
		}
	}

	/**
	 * Gets the {@link Connection} constant name corresponding to the given isolation.
	 *
	 * @param isolation The transaction isolation numeric value.
	 *
	 * @return The corresponding Connection constant name.
	 *
	 * @throws HibernateException If the given isolation does not map to JDBC standard isolation
	 *
	 * @see #toIsolationNiceName
	 */
	public static String toIsolationConnectionConstantName(Integer isolation) {
		final String name = ISOLATION_VALUE_CONSTANT_NAME_MAP.get( isolation );
		if ( name == null ) {
			throw new HibernateException(

View on GitHub (pinned to fad1729dce)

Solutions

1. Set 'hibernate.connection.isolation' to a numeric java.sql.Connection isolation constant or a supported level name
2. Remove or correct the invalid isolation level configuration

When it happens

Trigger: Thrown at hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/ConnectionProviderInitiator.java:363 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/90406fe4cb1f4b79. Report an issue: GitHub.