Question

It is possible for System administrators to define certain properties as final, so that client daemons may not override them.

However properties set using System.setProperty() method take preference over those set using Hadoop’s configuration API, in that case is it not possible for a client daemon to override a final property by setting it by calling System.setProperty()?

Thanks.

Answer 1

Note that while configuration properties can be defined in terms of system properties,
unless system properties are redefined using configuration properties, they are not accessible
through the configuration API

Internally, the hadoop system will access the configuration properties only through the Configuration interface. In case the user was unable to modify a configuration property through the Configuration interface (and he will be unable if the property is defined as final by the admin) the system will not see the modification the user made in the System’s properties