small fix for NPE race condition
small fix for NPE race condition

jankotek/MapDB,jankotek/mapdb,mebigfatguy/mapdb,morfeo8marc/mapdb,cocosli/mapdb,olupas/MapDB,olupas/MapDB,SleimanJneidi/mapdb,ringoluo/mapdb,ffjiao/mapdb,pettermahlen/mapdb,hangum/mapdb,binarytemple/mapdb,sumit784/mapdb,codeaudit/mapdb,jankotek/mapdb,mebigfatguy/mapdb,jankotek/MapDB,lamfire/mapdb