RRD4J is a 100% pure java implementation of RRDTool's functionality. It follows the same logic and uses the same data sources, archive types and definitions as RRDTool does. RRD4J supports all standard operations on Round Robin Database (RRD) files: CREATE, UPDATE, FETCH, LAST, DUMP, XPORT and GRAPH. RRD4J's API is made for those who are familiar with RRDTool's concepts and logic, but prefer to work with pure java. If you provide the same data to RRDTool and RRD4J, you will get exactly the same results and graphs. RRD4J is made from the scratch and it uses very limited portions of RRDTool's original source code. RRD4J does not use native functions and libraries, has no Runtime.exec() calls and does not require RRDTool to be present.