A Hemingway code-hero is a macho Alpha-male, a guy who indulges in manly pursuits such as drinking, hunting, and watching bullfights. He is an active, outdoors kind of person—a doer, not a thinker. Jake Barnes is very much the archetypal Hemingway code-hero, although his machismo is somewhat compromised by both his impotence and Brett Ashley's assertiveness. (It's a toss-up as to which is the more threatening to his masculinity).Code-heroes are none too comfortable with the thought of strong, independent women like Brett; they much prefer the women in their lives to be subservient and sexually available.
Aside from their hyper-masculinity and retrograde attitudes to women, code-heroes, as their name suggests, attempt to live their lives according to some kind of moral code. For Hemingway heroes like Jake, the rules by which they live are completely divorced from any religious beliefs. Though nominally a Catholic, Jake feels a distinct lack of spirituality in his life, and bemoans the fact that he cannot bring himself to believe in God. As a member of the post-WWI "lost generation," Jake constantly struggles against the ever-present threat of nihilistic despair, the life philosophy of "nada," or nothing. As life no longer has any meaning for him, like so many expats, he lives for the moment, indulging in the fleeting pleasures of food, drink, and pointless conversation.