Download : Programming : Library Components : A Java expression parsing library 
JEP is a Java library for parsing and evaluating mathematical expressions  MultiOS Software $550. JEP is a Java library for parsing and evaluating mathematical expressions. With this package you can allow your users to enter an arbitrary formula as a string, and instantly evaluate it. JEP supports user defined variables, constants, and functions. A number of common mathematical functions and constants are included.
JEP 3.0.0 1Jul07 English 1.4 MB
Features * Small size (only 160KB as jar archive) * Fast evaluation * High precision using BigDecimals * Includes common math functions and operators * Supports Boolean expressions * Extendable and configurable architecture * Support for strings, vectors and complex numbers * Support for implicit multiplication * Allows declared or undeclared variables * Java 1.5 compatible * Supports Unicode characters * Extensive documentation * Includes JavaCC grammar from which the main classes are generated
Java Math Expression Function Formula. Equation Parser Api Library Evaluate Mathematics Calculator Engine Parsing.  JEP
