RUPS

RUPS (short for “Really Useful Package Scanner”) is a lightweight, open‑source utility designed to examine the contents of Java Archive (JAR), ZIP, and other compressed file formats. Developed initially in 2005 by a community of Java developers, the tool provides a graphical interface that allows users to browse and inspect the internal structure of packaged applications without requiring extraction or compilation.

The primary purpose of RUPS is to aid developers, security analysts, and system administrators in quickly identifying class files, resources, and manifest entries within an archive. Its features include a tree‑view display of directory hierarchies, hexadecimal and plain‑text previews of selected entries, and the ability to compute and verify checksum values (MD5, SHA‑1) for integrity checks. RUPS also supports basic search functions, enabling users to locate specific class names, package paths, or string literals across large archives.

RUPS is written in Java, which allows it to run on any platform supporting a Java Runtime Environment (JRE) version 1.6 or later. The application is distributed under the Apache License 2.0, encouraging modification and redistribution. Because it does not modify the original files, RUPS is often employed in forensic analysis of software packages and in audit processes to detect embedded or malicious components.

Although primarily targeted at Java developers, RUPS has been adopted in broader contexts such as educational settings for teaching archive structures and in DevOps pipelines for automated verification of build artifacts. The project’s source code is hosted on public repositories, and new releases are periodically issued to address compatibility with newer JRE versions and to incorporate minor feature enhancements.