In Java, autoboxing and unboxing are features that allow you to convert between primitive data types and their corresponding object wrapper classes automatically. Autoboxing is the process of converting a primitive type to its corresponding object wrapper class, and unboxing is the process of converting an object of a wrapper class back to its corresponding primitive type.

Autoboxing and unboxing were introduced in Java 5 to simplify the process of working with primitive types and their object wrapper classes. Prior to Java 5, you had to manually convert between primitive types and their wrapper classes using methods like valueOf() and intValue().

Here is an example of autoboxing:

int x = 10;
Integer y = x; // autoboxing from int to Integer

In this example, the int value 10 is automatically converted to an Integer object and assigned to the y variable.

Here is an example of unboxing:

Integer y = 10;
int x = y; // unboxing from Integer to int

In this example, the Integer object with the value 10 is automatically converted to an int value and assigned to the x variable.

Autoboxing and unboxing can be used with all primitive types and their corresponding object wrapper classes, including int and Integer, double and Double, boolean and Boolean, and so on.

While autoboxing and unboxing can simplify the code and make it easier to work with primitive types and their object wrapper classes, it is important to note that they can have a negative impact on performance, especially in situations where large amounts of data are being processed. Therefore, you should use autoboxing and unboxing judiciously and consider the performance implications when working with large datasets.