While developing Magento modules/extensions, we often come up with a case where our module and some other module are rewriting/overriding the same core class. Hence, we get a conflict here and either our module or the other module will not function as expected.
There are some ways to avoid such conflicts. I will explain about two ways to do so.

Function addExpressionAttributeToSelect as defined in Mage_Eav_Model_Entity_Collection_Abstract (/app/code/core/Mage/Eav/Model/Entity/Collection/Abstract.php) allows us to use MySQL functions in Magento collection.
Here is an example of using MySQL function CONCAT in Magento customer collection to concat customer’s firstname and lastname:

Problem:
I am using Xubuntu (lightweight version of Ubuntu) and I am unable to type in local language using iBus (an input method (IM) framework for multilingual input in Unix-like operating systems).
iBus is already installed. When I go to its ‘Preferences‘ and then click the ‘Input Method‘ tab, I could only see ‘Chinese‘ language option in the dropdown list of ‘Select an input method‘. I am from Nepal, so I would like to see Nepali/Devnagari language option there.