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:355

			return isolationLevel;
		}
		else {
			final String string = setting.toString();
			if ( isBlank( string ) ) {
				return null;
			}
			else if ( ISOLATION_VALUE_MAP.containsKey( string ) ) {
				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.
	 *

View on GitHub (pinned to fad1729dce)

Solutions

1. Use a valid transaction isolation level name or constant (READ_UNCOMMITTED, READ_COMMITTED, REPEATABLE_READ, SERIALIZABLE) for 'hibernate.connection.isolation'
2. Correct the isolation level value in the configuration

When it happens

Trigger: Thrown at hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/ConnectionProviderInitiator.java:355 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/7c0c81f466a2fe6c. Report an issue: GitHub.