The patch fixes the NullPointerException which was thrown when Configuration.get() method is invoked.
The Configuration.processDeprecation() used to load the classes which were present as part of hadoop.conf.extra.classes key.
If one of those classes have a static block which does an Configuration.addResource(), the property map maintained by the Configuration is set to null causing the NullPointerException
After, offline discussion with Hemanth and Chaitanya with regards to correct fix, a new JIRA would be opened in order to discuss how best to expose the usage of
HADOOP-6105 to consumers, and this JIRA would provide a short term fix in which consumers are expected to change the static block in Configuration class for using HADOOP-6105