Sensor is a tool for monitoring the runtime performance of Java applications with as little overhead as possible. It can perform timing of application code and make other types of low-level measurements. It can be applied to Java applications in a number of ways, ranging from aspects to hardcoding, whichever you prefer.
Please read the Ideas Braindump page to get an idea about the goals, functionality, and scope of the project.
Not at the moment, although it won't be much longer. As soon as the core API has stabalized and we have some basic reporting, we will release a first public version for people to play around with. Until that time, please be patient.
Questions and comments are always welcome. Please send them to the mailing list.