Answer to Question #128134 in Java | JSP | JSF for Yann

Question

What are wrapper classes and why are they useful for ArrayLists? In your answer, include examples of autoboxing and unboxing.

Answer 1

The wrapper class is used to convert primitive types to objects. Since ArrayList is a generic class, it can only interact with objects, which is why wrapper classes for primitive types are used.

ArrayList<Integer> list = new ArrayList<>();
list.add(1);//autoboxing
int first = list.get(0);//unboxing