Comments on: The “I can’t find the object I put in the map” code blooper of the day http://sellmic.com/blog/2007/10/17/the-i-cant-find-the-object-i-put-in-the-map-code-blooper-of-the-day/ Augusto's corner of art, code and fun Thu, 02 Feb 2012 11:32:51 +0000 hourly 1 http://wordpress.org/?v= By: Scott Vachalek http://sellmic.com/blog/2007/10/17/the-i-cant-find-the-object-i-put-in-the-map-code-blooper-of-the-day/comment-page-1/#comment-879 Scott Vachalek Thu, 18 Oct 2007 12:23:21 +0000 http://sellmic.com/blog/2007/10/17/the-i-cant-find-the-object-i-put-in-the-map-code-blooper-of-the-day/#comment-879 Class objects are unique per ClassLoader so the equals() method is the same as the == operator. Class.equals() is probably the cleaner expression since it doesn't rely on you knowing how Class and ClassLoader are implemented, but in this case it's such a fundamental, common class that you can treat it a little differently. The instanceof thing is a good point too, but in all my years of programming / managing Java projects I don't think I've ever seen that bite anyone as an actual bug. Class objects are unique per ClassLoader so the equals() method is the same as the == operator. Class.equals() is probably the cleaner expression since it doesn't rely on you knowing how Class and ClassLoader are implemented, but in this case it's such a fundamental, common class that you can treat it a little differently.

The instanceof thing is a good point too, but in all my years of programming / managing Java projects I don't think I've ever seen that bite anyone as an actual bug.

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