The Modelica language is currently gaining increased interest; both in industry and in academia. Modelica is an object-oriented; general purpose modeling language; targeted at modeling of complex physical systems. While the main usage of models developed in Modelica is simulation; several other usages emerge. Examples of such usages are dynamic optimization; model reduction; calibration; verification and code generation for embedded systems. This paper reports the current status of the JModelica project; in which an extensible; Java-based Modelica compiler is being developed. In addition; an extension of the Modelica language directed towards dynamic optimization; Optimica; is discussed.