There is tooling to support authoring, parsing, and validation of CQL. There are open source tools available to evaluate the Expression Logical Model (ELM) for both the JavaScript and Java platforms. There is also a .NET toolkit for ELM that can support translation and evaluation.
Developing the measures in Java, C#, or any other commercially supported language would not achieve the goal of sharing the measure logic in a platform independent way, nor would it serve as a vehicle for communicating the intent of the measures in the way that CQL/ELM does. Traditional programming languages do not support the required set of operations for expressing measure logic, and traditional query languages, though closer to the mark, still do not support important aspects like terminology and interval-based timing. Refer to the GitHub tooling repository for additional guidance.