Teachers love talking about literary devices, but what exactly is a literary device?  Actually, it's just a fancier term for the different techniques writers sometimes employ to better create a mood or atmosphere, to put across an idea, to make a point, to describe a person, a thing , or an event.  It's a means to really get the reader to understand not only what is happening but also what is not happening.   The author is trying to make a point.  The literary device is just the name given to the technique he uses at that time and place in his work, to the way by which the writer says what he wants to really get the reader to understand.
The following is a list of literary devices that will be mentioned as we study The Catcher in the Rye.

allusion This is the term given to a reference to either a famous literary work or figure or to a famous historical event or person. 
dialect The way people from a particular region or group speak that is different from everyone else is called dialect.
dialogue Dialogue is the written conversation between characters. 
flashback A flashback is account of something that has already happened in the story.  A flashback usually involves an interruption in the action of the story.
foreshadowing Foreshadowing occurs when the author gives us a hint at something that is going to happen. 
hyperbole A statement that is an obvious exaggeration is called hyperbole.
idiom Idiom refers to the peculiarities of vernacular language.  It is the use of words in such a way that the meaning is lost if the expression is translated literally.
imagery This is the use of language to create a vivid picture and to put across an experience.
irony Irony is a figure of speech in which the actual meaning is the opposite of the words being used. 
mood The atmosphere created by the writer is called mood.
point of view Point of view refers to the "eyes" through which the story is told.    
stream of consciousness In this writing technique the writer tries to capture the exact flow of the  character's thoughts.   
symbols A symbol is an image that represents something other than itself.
tone The feeling or effect that a writer creates toward his characters or his subject is tone. 

(Massachusetts English Language Arts Learning Standards 8, 12, 15)