[Hama Wiki] Update of "HowToContribute" by ChiaHungLin

[Apache Wiki <wi...@apache.org>]

Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hama Wiki" for change notification.

The "HowToContribute" page has been changed by ChiaHungLin.
http://wiki.apache.org/hama/HowToContribute?action=diff&rev1=7&rev2=8

--------------------------------------------------

  
  Contributors should join the Hama mailing lists. In particular, the commit list (to see changes as they are made), the dev list (to join discussions of changes) and the user list (to help others).
  
+ === Coding convention ===
+ 
+  * Variable should be meaningful. For instance, the declaration of `String colum' would be better than `String str'. 
+  * Indentation is 2 spaces, not 4.
+  * Argument checks for [[http://download.oracle.com/javase/6/docs/api/java/lang/NullPointerException.html|NullPointerException]], [[http://download.oracle.com/javase/6/docs/api/java/lang/IllegalArgumentException.html|IlleagalArgumentException]], etc.
+ 
  === See also ===
  
   * [[http://www.apache.org/dev/contributors.html|Apache Contributor Documentation]]