Boxing and Widening

Question

What is the difference between these two. I know Boxing is converting primitive values to reference. What is widening. Also what should be the sequence first boxing should b

Answer 1

Widening is transforming a variable in another with a wider type.
Widening can be done with primitive or reference types.

For example :

String -> Object
int -> long

As the JLS states :

a boxing conversion (§5.1.7) [is] optionally followed by a widening reference conversion

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Resources :

• JLS - Widening Primitive Conversion
• JLS - Widening Reference Conversions