Java Automatic Packaging (automatic boxing)

Boxing (encapsulating objects), that is, an object that converts an underlying data type (such as int) into an underlying type wrapper class (such as New Integer ())
Unpacking is the inverse of boxing, which is to convert an object of the underlying type encapsulation class (such as New Integer ()) to the underlying data type (such as int).
The wrapper functionality works for all basic types and wrapper types:

Java Learning automatic packing and automatic unpacking source analysis

Java Automatic Packaging (automatic boxing)