rrd4j RRD4J is a high performance data logging and graphing system for time series data, implementing RRDTool's functionality in Java. It follows much of 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, EXPORT and GRAPH. RRD4J's API is made for