private void setDeprecatedPropertiesForUpgrade ( Properties props ) { deprecatedProperties = new HashMap < String , String > ( ) ; String md5 = props . getProperty ( MESSAGE_DIGEST_PROPERTY ) ; if ( md5 != null ) { deprecatedProperties . put ( MESSAGE_DIGEST_PROPERTY , md5 ) ; } }
Pull any properties out of the VERSION file that are from older versions of HDFS and only necessary during upgrade .