jfftw3 provides JNI access to FFTW, an open source C library for the computation of discrete Fourier transforms. jfftw3 consists of a thin native wrapper for the FFTW 3.2 library. The wrapping covers FFTW's memory allocation, basic planner interface, and wisdom handling. The native wrapper is designed to support automatic JNI generation by gluegen into a useful Java API providing the original procedural FFTW interface.
UPN-Calc is a RPN (Reverse Polish Notation) calculator for mobile devices that support J2ME and MIDP 1.0. It features arbitrary precision unnormalized BCD arithmetic and provides many scientific standard functions, such as sin, cos, tan, arcsin, arccos, arctan, 1/x, sqrt(x), exp(x), ln(x), and y^x.