Where are your sources? John was the son of Solomon Holman III (b. 1723) and Sarah (Waite) Holman. He was born Sept. 2, 1766 at Lancaster, MA.
Sources:
* https://www.familysearch.org/ark:/61903/3:1:S3HY-6P97-59D, Solomon Holman entry for John Holman, Sept 24, 1766 and David Holman, June12,1770 ; citing Births, Lancaster, Worcester, Massachusetts Bay, British Colonial America, The birth, marriage, and death register, church records and epitaphs of Lancaster, Massachusetts, 1643-1850; FHL 004362848
* Holman, David Emory. The Holmans in America; Concerning the Descendants of Solaman Holman. New York: The Grafton Press, 1909. Page 12
Capt. Solomon Holman had only 12 children, none of them named John.
See The Holmans in American page 6, and Wikitree Solomon Holman Jr. (1697-1785).