Have you heard about boxing and unboxing in Java?

Yes, I have heard of it. Boxing and unboxing in Java are automatic conversions between primitive data types and their corresponding wrapper classes.

Boxing: Automatic conversion of a primitive type to an object of the corresponding wrapper class.

Unboxing: Automatic conversion of a wrapper class object back to its primitive type.

Examples:

// Boxing
int primitiveInt = 10;
Integer wrappedInt = primitiveInt; // Automatic boxing

// Unboxing
Integer anotherWrappedInt = 20;
int anotherPrimitiveInt = anotherWrappedInt; // Automatic unboxing

Boxing and unboxing were introduced in Java 5 to simplify working with collections and methods that expect objects rather than primitives.

It is important to remember that boxing and unboxing can affect performance due to the creation of new objects and can lead to NullPointerException during unboxing if the wrapper object is null.