J.C. O'Connor appears to be a relatively obscure author with limited information available.
O'Connor's primary contribution to the literary world seems to be in the realm of Esperanto. He authored at least one textbook on the language titled "Esperanto: The student's complete text book". This book covers grammar, exercises, conversations, commercial letters, and a vocabulary.
While there's some information about his book and its availability on platforms like ThriftBooks, Project Gutenberg, and MW Books, biographical details about the author himself are scarce.