for (int i = 0; i < nThreads; i++) {
    executorFlushObjectToDB.execute(new FlushObjectToDB(...));
}

public class FlushObjectToDB implements Runnable {
    ...
    @Override
    public void run() {
        try (Connection connection
                = HikariConectionFactory.getConnection();
                PreparedStatement prStatement
                = connection.prepareStatement(sqlInsertObjectProp)) {
             connection.setAutoCommit(false);

             for (...) {
                 prStatement.setString(1, ".....");
                 prStatement.setString(2, ".....");
                 prStatement.addBatch();
             }
              
             prStatement.executeBatch();
             connection.commit();

        } catch (SQLException ex) {
             throw new RuntimeException(ex);
        }
    }
}