Boxing/Unboxing: Boxing is the process of converting a primitive data type into its corresponding wrapper class object, while unboxing is the reverse process.
Autoboxing/Auto-unboxing: Autoboxing refers to automatic conversion between primitive types and their corresponding wrapper classes, while auto-unboxing refers to automatic conversion from wrapper class objects back to their respective primitive values.
Integer vs int (or other similar pairs): Integer is a wrapper class for int in Java. The main difference is that Integer is an object and can be used in situations where objects are required, while int is a primitive data type and has no methods or properties associated with it.