Autoboxing is a feature in Java that allows for the automatic conversion between primitive types and their corresponding object wrapper classes. For example, converting an int to an Integer, a double to a Double, and so on. This conversion is done by the Java compiler, and is called autoboxing. If the conversion goes the other way, from an object wrapper class to a primitive type, this is called unboxing.
Autoboxing is useful because it allows for the use of primitive types in situations where object types are required, such as when using collections or generics. For example, a List<Integer> can hold a list of integers, but not a list of int values. Autoboxing allows for the automatic conversion of int values to Integer objects, so they can be added to the list.
Here are some key points about autoboxing in Java:
- Autoboxing is the automatic conversion of primitive types to their corresponding object wrapper classes, and unboxing is the opposite conversion from object wrapper classes to primitive types.
- Autoboxing is done by the Java compiler, and is useful for situations where object types are required, such as when using collections or generics.
- Autoboxing can have performance costs associated with it, so it should only be used when there is an "impedance mismatch" between reference types and primitives.
- Autoboxing and unboxing can be illustrated with examples that use generics and the for-each loop.
