21. What is the primary advantage of using generics in Java?
22. Which of the following is NOT a generic type parameter in Java?
23. What is the purpose of the `get(int index)` method in a generic list in Java?
24. In Java generics, what is the purpose of the `Pair` class?
25. What does the term "type erasure" mean in Java generics?
26. In Java, which generic class is commonly used for creating key-value pairs?
27. What is the result of the following Java code?
List list = new ArrayList<>();
list.add(new Object());
List list = new ArrayList<>();
list.add(new Object());