No Runtime, No Signal: Java Energy Prediction Beyond Static Metrics
TL;DR for operators A development team wants to identify energy-expensive Java methods early, without repeatedly profiling every code change on controlled hardware. Source-level features such as complexity, calls, loops, and control flow appear to offer a cheap signal because they can be extracted before the software runs. In this study, those features were almost useless without runtime evidence. When the researchers reran the same Random Forest prediction setup after removing execution time, predictive $R^2$ fell from 0.454 to 0.005. Code features that look operationally meaningful therefore provided almost no useful prediction until a timing signal was added. ...