The Shared Scientific Toolbox is a library that facilitates development of efficient, modular, and robust scientific/distributed computing applications in Java. It features multidimensional arrays with extensive linear algebra and FFT support, an asynchronous, scalable networking layer, and advanced class loading, message passing, and statistics packages.
jniThreadCPUUsage is a Java library to get the amount of user and system CPU time used per thread. This is done via JNI, which calls getrusage() on the system. getrusage() is only available on Linux 2.6.26 or later and Solaris. One useful application of this is measuring the amount of CPU time used for a servlet request. getrusage() CPU time reporting is better than using the real time clock because it measures actual CPU time used and disregards times when the thread is idle or waiting (such as when it is waiting for network I/O).