what is the purpose of the judiciary

The judiciary is the branch of government which administers justice according
to law. The term is used to refer broadly to the courts, the judges, 
magistrates, adjudicators and other support personnel who run the system. 
The courts apply the law, and settle disputes and punish law-breakers according
to the law

Here is what the above code is Doing:
1. It is defining the term judiciary as the branch of government which administers justice according to law.
2. It is stating that the judiciary is responsible for the courts, judges, magistrates, adjudicators, and other support personnel who run the system.
3. The judiciary is responsible for applying the law, settling disputes, and punishing law-breakers according to the law.