The Commons Math project aims at creating consistent, self-contained, state-of-the-art, pure Java implementations of standard mathematical algorithms. The focus is on numerical processing in double-precision, covering a wide range of topics (ordinary differential equations, statistics, linear algebra, random number generation, optimization, and others). Contributions are mainly driven by use-cases arising from real-world applications. Development is based on clean, maintainable, object-oriented design and extensive documentation.