Improvement from io -> nio, then -> MappedByteBuffer - http://dobbscodetalk.com/index.php?option=com_myblog&show=File-IO-in-Java.html&Itemid=29 How to improve performance by tuning the IO - http://pzemtsov.github.io/2015/01/19/on-the-benefits-of-stream-buffering-in-Java.html