What causes "Could create JDBC statement" in testcontainers/testcontainers-java?

Verify the connection is open (connection.isClosed()) before using the delegate

testcontainers/testcontainers-java · error · ConnectionCreationException

Could create JDBC statement

Error message

Could create JDBC statement

What it means

ContainerLessJdbcDelegate's createNewConnection throws ConnectionCreationException when connection.createStatement() fails. This delegate runs SQL against an existing external database without a container, so it fails when the supplied JDBC connection cannot produce a Statement.

Solutions

Verify the connection is open (connection.isClosed()) before using the delegate
Re-create the connection via DriverManager before delegating
Check the chained SQLException cause for the vendor error code
Ensure single-threaded or synchronized use of the underlying connection

Example fix

// before
new ContainerLessJdbcDelegate(closedConnection).execute(sql, ...);
// after
if (connection.isClosed()) connection = DriverManager.getConnection(url, user, pass);
new ContainerLessJdbcDelegate(connection).execute(sql, ...);

Defensive patterns

Strategy: validation

Validate before calling

if (connection == null || connection.isClosed()) {
    connection = DriverManager.getConnection(url, user, password);
}

Try / catch

try {
    delegate.execute(statement, 0, null, null);
} catch (ConnectionCreationException e) {
    log.error("Statement creation failed on external DB", e.getCause());
    throw e;
}

Prevention

Check connection.isClosed() before creating the delegate
Use a fresh connection per delegate instance
Avoid sharing connections across threads

When it happens

Trigger: Using ContainerLessJdbcDelegate with a closed, invalid, or broken connection whose createStatement() raises SQLException.

Common situations: Connection already closed after pool eviction; connection created with a bad URL; reusing a connection across threads after it was invalidated.

Understand the failure class

Background: ECONNREFUSED and "connection refused" / "could not connect to server" errors: what they mean and how to fix them — this error's family across 44 libraries.

Related errors

AI-assisted analysis of testcontainers/testcontainers-java@8e549514e3 (2026-09-12). Data as JSON: /api/errors/d04399b1925f0a91. Report an issue: GitHub.

Appendix: source

Thrown at modules/jdbc/src/main/java/org/testcontainers/jdbc/ContainerLessJdbcDelegate.java:33

 * @see org.testcontainers.ext.ScriptUtils
 */
@Slf4j
public class ContainerLessJdbcDelegate extends JdbcDatabaseDelegate {

    private Connection connection;

    public ContainerLessJdbcDelegate(Connection connection) {
        super(null, "");
        this.connection = connection;
    }

    @Override
    protected Statement createNewConnection() {
        try {
            return connection.createStatement();
        } catch (SQLException e) {
            log.error("Could create JDBC statement");
            throw new ConnectionCreationException("Could create JDBC statement", e);
        }
    }
}

View on GitHub (pinned to 8e549514e3)