I have started to see variable initialisations like that in Java libraries:

Class clazz = new Class();


Class klass = new Class();

Is there a particular reason for people to misspell the word "class" when declaring these variables, and to use a "kool boyz" sort of writing style? Also what is wrong with using something like cls or something similar?

  • 1
    Honestly, I did not see this "often" before, as your question title presumes (except when the author of the code had some kind of dyslexia).
    – Doc Brown
    Jan 14, 2014 at 7:25
  • It's not often and it should not be! If don't know how to call an object it clearly means you don't know what the code should do. This simply tells you that your code stinks: en.wikipedia.org/wiki/Code_smell
    – SOReader
    Jan 14, 2014 at 9:43
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    I, as the OP, did not use the "often" adverb. My question was edited.
    – Sarp Kaya
    Jan 14, 2014 at 10:18
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    I removed "often" from the title (someone else edited it in for you), but I voted to close it as a duplicate anyway. Jan 14, 2014 at 10:28

2 Answers 2


This is a special case with the name class, as that is a reserved keyword in some languages such as Java and thus cannot be used as the variable name. Using clazz or klass is a way to workaround that. Other options would include e.g. myClass.

In Java it's pretty common, as even the JDK uses that convention. See also https://stackoverflow.com/a/2530174/160539

"class" is what you want, but abbreviating or inserting junk ("a", "the", "_", etc) reduces clarity. clazz just says class. "International" English speakers (those reading both English and American) are used to transposing 's' and 'z'.

Since Java has had disclosed source and a suitable culture right from the start, worthwhile Java code and tutorials pick up the same conventions...

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    Also note the use of C#'s "@" for variable-naming if you're really set on using a keyword (assuming that's your language of choice).
    – J Trana
    Jan 14, 2014 at 5:55
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    I'd consider such usage to be a code smell.
    – user28988
    Jan 14, 2014 at 7:41
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    @DocBrown In Java it's pretty common, as even the JDK uses that convention. See also stackoverflow.com/a/2530174/160539
    – msell
    Jan 14, 2014 at 7:45
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    If Java programmers like to use this kind of variable naming, then Java programmers smell just like their code.
    – gbjbaanb
    Jan 14, 2014 at 9:01
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    @msell: looking at that link, I guess it's pretty common in Java for meta programming, where you have programs dealing with classes and methods itself (and not pretty common in general). That makes more sense for me.
    – Doc Brown
    Jan 14, 2014 at 11:29

If you really have to use a reserved word, then in .NET you can escape it like this:

var @class = new Class();

In my mind it's better than calling something 'klass'. I won't be surprised if other languages (JAVA) offer something similar.

Generally I would avoid 'cls', 'klass' or anything that requires additional mind mapping. It's a background noise and it's not needed.

  • Java doesn't "offer anything similar"
    – gnat
    Jan 14, 2014 at 10:29

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