With Great Power Comes Great Responsibility

Abstract

As the energy consumption of the ICT sector continues to grow, there is an increasing need for developers to reason about the energy efficiency of their code. However, most energy measurement tools operate at the application level and require significant workflow disruption, leaving developers without accessible, in-situ feedback during development. In this thesis, we investigate the technical and practical feasibility of a lightweight, software-based energy measurement tool for Java code snippets, implemented as an IntelliJ IDEA plugin backed by a JShell execution environment and the Linux powercap framework. To evaluate the proposed tool, we conduct a two-phase study. In a verification phase spanning 30 algorithmic problem pairs and 1800 measurements, the tool detects statistically significant energy consumption differences in 83.3% of cases. In a mixed-methods validation study with 22 participants, accuracy in identifying the more energy-efficient implementation rises from 56.8% when relying on source code inspection alone, to 97.7% when using the tool, alongside an increase in participant confidence. Qualitative analysis further reveals that the tool assists in correcting flawed intuitions and provides educational value. These results suggest that fine-grained, in-IDE energy measurement is both technically achievable and empirically beneficial, and constitutes a concrete step toward making energy-aware development a routine part of software engineering practice.