Beside the classical problems that can be addressed with application modules, the core Multiphysics package can be used to solve PDEs in weak form. An API for Java and MATLAB can be used to control the software externally. The program also serves as an application builder for physics applications. Several modules are available for COMSOL, categorized according to the applications areas of Electrical, Mechanical, Fluid, Acoustic, Chemical, Multipurpose, and Interfacing.