After reading John-Paul Satre's "The Childhood of a Leader- and being made aware of it's existential undercurrent, it now seems obvious that there are existential aspects to all the works studied so far. Existentialism sees humans as free and self determining agents who are products of existence rather than essence; nurture opposed to nature. I believe in all the works the protagonists are confronted with questions and choices, the responses to which decide their character. In this way they can choose their own personality.
Existentialists are individuals who are willing to live their lives both within and without the system that frames their identity and that is exactly who Holden Caulfield is. In "The Catcher in the Rye-, he has no real interest in school or any other institution. He is a true individual and a free spirit, and cares little for society and it's rules. In these respects he could be described as an existentialist. Furthermore, despite Holden's reluctance to grow up, "The Catcher in the Rye- is still described as a bildungsroman. He may not believe that he has changed at the end of the novel when he says that he's not going to apply himself next year, but having had the experiences and pain he describes it seems logical that he has matured and learnt about himself. When Holden tries to rub out the graffiti at Phoebe's school in order to protect the minds of the innocent children he is becoming the catcher in the rye. This is reinforced at the end of the book when he purports to miss everyone mentioned, one feels that he would like to have protected them and caught them in the rye like the children, he doesn't want them to have grown up. In this way at least he is defining himself by his own actions, and has developed into if nothing else the catcher in the rye and an existentialist. This novel is not one of overt Existentialism like "The Childhood of a Leader-, I have no idea of Salinger's philosophical orientation, but it is implicit that Holden is capable of freely making many different choices and only when made can he learn about himself.