According to the book "Hadoop; The Definitive Guide", it is possible to use "-D property=value" to
override any default or site property in the configuration.
I gave it shot and it is true. The property specified with "-D" is ignored.
Then I put the property in an xml file and use "-conf xml_name" on the command line. But still I cannot
override the property.
The only way to override the default property is to get a Configuration reference in the code and set the property via the reference. But that is not convenient as I need to recompile the code each time I change the property.
Now the question is what is the right way to customize the configuration for a job?