question: @ VisibleForTesting protected Map < String , String > calculateModifiedServerDefaults ( Map < String , String > newDefaults , Map < String , String > existingDefaults , Set < String > attrToModify ) { Map < String , String > modifiedValues = new HashMap < String , String > ( ) ; for ( String attrName : attrToModify ) { String newAttr = newDefaults . get ( attrName ) ; String existingAttr = existingDefaults . get ( attrName ) ; if ( newAttr != null && existingAttr != null && ! newAttr . equals ( existingAttr ) ) { modifiedValues . put ( attrName , newAttr ) ; } } return modifiedValues ; }
target:  Only include in the list of modified attributes those that are listed in the serverupgrade.properites file; otherwise existing properties that have been locally modified would be over-written.