Those songs were used in his movie about George M. Cohan--an Irish boy. Those were Cohan's songs. Cagney portrayed Cohan in the movie. The movie is "Yankee Doodle Dandy." The songs are from before WWI.
http://www.imdb.com/title/tt0035575/Edited by Alferd Packer at 14:51:40 on 08/26/17