import org.mariuszgromada.math.mxparser.*; Expression expression = new Expression("2 + 3 * 4"); double result = expression.calculate(); <mathparser-config> <operators> <operator value="%" type="infix" priority="1" associativity="left"/> </operators> <functions> </functions> <variables> </variables> <constants> </constants> </mathparser-config> ExpressionConfiguration conf = new ExpressionConfiguration(); conf.loadFromXML("mathparser_config.xml"); Expression.setConfiguration(conf);