What themes of social reform and injustice are addressed in the novel Great Expectations?

Some of the important themes of social reform and injustice are as follows:

1.Child abuse:the childhood of Joe, Pip, Estella and Magwitch is pitiably abusive. Ch.7 "And he hammered at me (Joe) with a wigour."  Ch.8 "Within myself,I (Pip) had sustained, from my babyhood a perpetual conflict with injustice."  Ch.33 "You had not your little wits sharpened by their intriguing against you...I (Estella) had." Ch.42 "I (Magwitch) was a ragged little creetur as much to be pitied as ever I see."

 2. The Crooked Legal System: Compeyson is treated sympathetically by the judge and is awarded a lesser jail term. Ch.42 "And when we're sentenced ain't it him as gets seven years and me (Compeyson) fourteen."

3. The Educational System : Ch.10, Mr. Wopsle's great aunt's school. Ch.23 Mr.Pocket's method of tutoring Pip and his companions.

4. The hypocrisy of the prevailing Class System: The central theme of the novel,of course, is "Who is a true gentleman?" Ch.22 "It is a principle of his(Matthew pocket) that no man who was not a true gentleman at heart, ever was, since the world began, a true gentleman in manner. He says, no varnish can hide the grain of the wood; and that the more varnish you put on, the more the grain will exress itself." In which case the true gentleman in the novel would  be Joe and only Joe.