Some thoughts on your comment:

- I usually use JODA or a Calendar (if I have to)

- I wanted to stay close to the Ruby example, as the preface states: “This article contains code examples, which could be written better and which experienced Java and Ruby developers would write differently.”

- As said there is no full code. These were some code example to illustrate the CC points made in the post (”But the examples were chosen to illustrate points”).

- new Date(1,1,1935) is deprecated. you can use GregorianCalendar instead. Java 7 will have better datetime handlin tough.

- you can use static import for SongType in Java code, it would reduce the code crowd. as: SongType.TRAD_JAZZ -> TRAD_JAZZ

Lastly,

if (song.isMp3Type(Mp3Jazz.class) sounds a little awkward to me. it smells a little but cannot say much before i see the full code.