In Cool Hand Luke, describe instances of "harsh oppression." In the end, was justice restored for Luke? Why or why not?

In the film Cool Hand Luke, the title character, having gotten drunk, begins walking down a dark street late at night and, using a pipe wrench, cuts the tops off parking meters. There is no indication that Luke wants to steal the money. Rather, it is the impulse of an independent actor to defy the system. It is an act against authority rather than an act of selfishness. Luke is subsequently arrested and sentenced to serve his two-year sentence on a chain gang.
In the context of the phrase "harsh oppression," one could conclude that a two-year sentence on a prison work farm is the harsh and oppressive response of the system to Luke's act of defiance, which could be seen as a threat to the status quo. It is a metaphor for the impersonal revenge of the powerful upon the weak.
The prison work farm is run by a sadistic guard, the Captain, who, with gentle menace, recites the rules of conduct. Luke, as expected, resists following the rules, tries to escape the work farm, and is viciously punished for his infractions when captured, and he always is captured. In a parody of modern social psychology, the Captain refers to Luke's rule-breaking as "a failure to communicate." Harsh oppression at the hands of the guards is evident in the punishments but not in the words. Again, this is the system's denial of its harsh authority through the use of measured language. Just as a judge has harshly sentenced Luke in the impersonal accepted language of the court, the Captain has harshly sentenced Luke in similar impersonal terms. The language of power is neutral.
At the work farm, prisoners have little else but a striped uniform, leg chains, and an earned place in the jailhouse pecking order. Luke's instincts toward defying authority work against him not just among the guards, but also among the inmates. A fistfight between him and the top convict nearly results in Luke's death, but Luke's defiance enables him to survive the fight and fuels the grudging admiration of his fellow convicts, most of all the man who almost killed him. Again, resisting the authority of a system, even as informal a system as the work farm pecking order, results in the use of harsh oppression.
Luke so thoroughly resists the prison work farm's discipline that he, in the end, is killed rather than recaptured while trying, again, to escape. Metaphorically, the Captain can be seen as mayor of this environment and the senior guard as head of his police force. The system always had authority to shoot and kill Luke as an escapee but refrained from using it in an effort to break his will. Based on finally realizing that Luke was never going to respect their authority, they delivered this harshest oppression.
Harsh oppression, while meted out continually against Luke, never has the desired result, as Luke never relents. In the end, in some sense, Luke's justice is restored, but only in the sense that all people gain some sort of liberation upon death. Luke's mission, while masochistic, is not suicidal, so his death does not restore his justice, but it does create a martyr.
As in the case of other martyrs, the prisoners who share the environment with him see his demise as restorative, in the sense that they can remember Luke, smile, recount his tales, and mythologize him. They also understand that Luke's murder undermines the authority of the system—it is an act of resignation and defeat, which gives them solace and pride.