Like with any language, the level of abstraction is up to you... one could just as easily "lose control" with C++. Hundreds or thousands of times slower Java?

Like with any language, the level of abstraction is up to you... one could just as easily "lose control" with C++. Hundreds or thousands of times slower Java? Have you considered that the conversion was done with a weak mastery of the language or runtime? The HFT folks working in Java would be taken aback to learn the language doesn't work.