SCJP: can't widen and then box, but you can box and then widen <p>I'm studying for the SCJP exam and I ran into an issue I can't really wrap my head around.</p> <p>The book says you can't widen and then box, but you can box and then widen. The example for not being able to box is a method expecting a Long and the method being invoked with a byte.</p> <p>Their explanation is:</p> <blockquote> <p>Think about it…if it tried to box first, the byte would have been converted to a Byte. Now we're back to trying to widen a Byte to a Long, and of course, the IS-A test fails.</p> </blockquote> <p>But that sounds like box and then widen and not widen and then box to me.</p> <p>Could anyone clarify the whole box and widen vs widen and box for me because as it stands the book isn't exactly clear on the issue.</p> <p>Edit: To clarify: I'm talking about pages 252 and 253 of the SCJP sun certified programmer for java 6 book. <a href="http://books.google.be/books?id=Eh5NcvegzMkC&amp;pg=PA252#v=onepage&amp;q&amp;f=false" rel="nofollow noreferrer">http://books.google.be/books?id=Eh5NcvegzMkC&amp;pg=PA252#v=onepage&amp;q&amp;f=false</a></p>