question: @ NotNull public List < PlayerNbt > createMultiplayerPlayerNbts ( ) { List < PlayerNbt > result = new ArrayList < PlayerNbt > ( ) ; for ( File playerdataFile : getPlayerdataFiles ( ) ) { if ( playerdataFile . isFile ( ) ) { result . add ( createPlayerdataPlayerNbt ( getPlayerUUIDFromPlayerdataFile ( playerdataFile ) ) ) ; } } if ( ! result . isEmpty ( ) ) { Log . i ( "using players from the playerdata directory" ) ; return result ; } for ( File playersFile : getPlayersFiles ( ) ) { if ( playersFile . isFile ( ) ) { result . add ( createPlayersPlayerNbt ( getPlayerNameFromPlayersFile ( playersFile ) ) ) ; } } if ( ! result . isEmpty ( ) ) { Log . i ( "using players from the players directory" ) ; return result ; } Log . i ( "no multiplayer players found" ) ; return result ; }
target:  Since version 1.7.6, minecraft stores players in the playerdata directory and uses the player uuid as filename.