From chapters 22 and 23 of To Kill a Mockingbird, what literary techniques are used?

Literary techniques, sometimes called narrative techniques, encompass many different strategies that authors use to tell a story. Some examples of literary techniques include juxtaposition, the use of foils, flashbacks, plot twists, and foreshadowing. Chapters 22 and 23 detail events that take place after the Tom Robinson trial. Jem, specifically, struggles through the painful effects of a bildungsroman--otherwise known as a coming-of-age story. For example, Lee tracks Jem's steps from the courtroom to Miss Maudie's house, then to having discussions with Atticus about what occurred during the trial. Jem is baffled that Tom was not allowed to go free. He describes his disappointment with a simile as follows:

"It's like being' a caterpillar in a cocoon, that's what it is . . . Like somethin' asleep wrapped up in a warm place. I always thought Maycomb folks were the best folks in the world, least that's what they seemed like" (215).

Jem's disenchantment with the people of his town opens up the way for him to realize the realities of life in the South. What seemed like a good life in Maycomb is now destroyed by Jem's experience with the prejudices shown during the trial of Tom Robinson. Jem's naive hope that the world always seeks what's right, or that truth will always prevail, is destroyed. As a result, a boy faces the realities of the adult world and must come to terms with them. Consequently, he will never be able to return to his child-like, naive self. 
In chapter 23, discussions at the Finch house become more serious in nature. Jem's brain is filled with questions as he seeks answers while going through his rite of passage. Jem doesn't understand why Tom Robinson would get the death penalty for a conviction of rape. This leads Atticus to teach his son that the problem lies with the prejudices against African Americans, not the law. Atticus gives Jem a lesson on the following clarifying truth:

"As you grow older, you'll see white men cheat black men every day of your life, but let me tell you something and don't you forget it--whenever a white man does that to a black man, no matter who he is, how rich he is, or how fine a family he comes from, that white man is trash" (220).

Thus, Atticus teaches his son about the realities of the adult world in the South. Jem must face these facts and make a decision about what type of man he will become. Therefore, the primary technique used in chapters 22 and 23 is a bildungsroman because the focus is on explaining to Jem about what actually happened during the Tom Robinson trial. Once Jem accepts these new realities, he will enter the world of adults.  
One other technique used in chapter 23 has to do with creating foil characters with Atticus Finch and Bob Ewell. Foils are two characters who are complete opposites of each other. They are pitted against each other to show the difference between two different thoughts, philosophies, or agendas. For example, Atticus represents everything good, wholesome, proper and fair. On the other hand, Bob Ewell is disgusting, uneducated, ill-mannered, and a liar. When Bob Ewell challenges Atticus to a fight, he is disappointed that Atticus's response is that he's too old to fight. As a result, Atticus comes off looking like the better man on so many levels. Not only is Atticus kind and compassionate, but he doesn't hold a grudge towards one of the meanest men in Maycomb, either. For instance, Atticus tells Jem the following about Bob Ewell:

"Jem, see if you can stand in Bob Ewell's shoes a minute. I destroyed his last shred of credibility at that trial, if he had any to begin with. The man had to have some kind of comeback, his kind always does. So if spitting in my face and threatening me saved Mayella Ewell one extra beating, that's something I'll gladly take" (218).

Not only does Bob Ewell spit in Atticus's face, but he also calls him derogatory names in public. Atticus doesn't respond because he can't be provoked to lower himself to Ewell's level. By pitting an evil man against one of the kindest, most loving, and self-contained characters, Lee creates an excellent example of the use of foils to drive her plot forward. The discussions about Bob Ewell in the Finch home after the threatening public display center around protecting themselves from future attacks. These family discussions, and subsequent worries about Ewell by the children, foreshadow the attack on Jem and Scout later on in chapter 28. The following exchange between Atticus and Alexandra can be viewed as a foreshadowing:

"We don't have anything to fear from Bob Ewell, he got it all out of his system that morning.'"
"'I wouldn't be so sure of that, Atticus,' [Aunt Alexandra] said. 'His kind'd do anything to pay off a grudge. You know how those people are'" (218).

Aunt Alexandra's words ring true in the end; therefore, this is a foreshadowing of things to come from this point in the story.