How does Jem mature in To Kill a Mockingbird?

Although Scout learns a few lessons through out the story, Jem is the one who matures and learns. You can see this as his opinions about the court case change and he sees the bigger picture of why Tom really is innocent and what is wrong with the jury/ society in determining Tom's fate. Also how he treats Scout, his actions and Words change throughout the book all indicate that he's maturing throughout the story.