Check out our project page to learn more (downloads, docs): Java Simon was overhauled since the first version (it's not compatible with it) and you can expect following changes: * object Split was introduced (returned by stopwatch start) to provide better flexibility for single/multi-threaded environment; * you can extend Java Simon behavior via Callbacks and hook your own functions on various events; * JMX and Spring support tools was added; * Maven 2 is supported ( repository). What stays the same: * you can measure splits, stopwatch provides total time, number of time splits, tracks max/min time, time stamps when extremes were measured, deviation, variance, first/last usage time stamp - of course enable/disable and reset features are provided too; * time split is measured in nanoseconds (hence JDK 1.5 or higher is required) - of course timestamps are in millis; * all monitors are stored in a tree hierarchy similar to java.util.logging API - this provides powerful features like enable/disable/reset of the whole subtrees of this monitor hierarchy; * simple to use JDBC Proxy driver; * and finally we think we still keep our documentation standards. See us on the project page (, on or join the group