Java Upgrade

Before you start: read this whole install prompt, tell me in a few lines what this skill does and what installing it involves, and wait for my go-ahead before you do anything else. Prerequisites: A Java project and local Java tools (a JDK for the target version, Maven or Gradle). No account, no API key and no paid service is needed to install or use the skill itself. At use time the skill tells the agent to fetch the official guide for the target version before editing (pages on openjdk.org, docs.oracle.com, docs.gradle.org and docs.openrewrite.org), and build tools download updated dependencies from your configured repositories. Optional and separate, disclosed here because SKILL.md proposes it: the Microsoft modernize-java plugin is installed through GitHub Copilot (npm install -g @github/copilot, then a Copilot plugin marketplace add and install), which needs a GitHub account and a Copilot setup; this skill works without it and never requires it. Install "Java Upgrade" for me. Step by step guidance to upgrade a Java project to a newer JDK and adopt new language features safely. The skill detects the current version from the build files, asks for the target if it is not stated, upgrades one LTS at a time (11 to 17, 17 to 21, 21 to 25), builds and tests after each step, updates the build first, and loads only the per version guide needed from its three reference files. It covers the javax to jakarta namespace safeguards, points to OpenRewrite recipes for automated changes, and lists the official upstream sources to fetch for the target version before editing. A separate, more powerful Microsoft plugin (modernize-java, through GitHub Copilot) is presented as an optional alternative for large upgrades; it is not part of this skill. Repository: https://github.com/github/awesome-copilot (the skill is the whole skills/java-upgrade/ folder at the pinned commit: SKILL.md, references/java-11-to-17.md, references/java-17-to-21.md, references/java-21-to-25.md, references/upstream-sources.md) Pinned version: install the code at commit cb64ad12e32737ae764becd6885462e9b4c7cb00 exactly. Do not substitute a newer version. If this commit is unreachable, stop and tell me. 1. Clone https://github.com/github/awesome-copilot into a temporary folder, check out commit cb64ad12e32737ae764becd6885462e9b4c7cb00, and copy the skills/java-upgrade/ folder from that checkout. Then compare every file in the folder with the fingerprints recorded for this listing on 2026-10-18: [FINGERPRINTS] - SKILL.md: SHA-256 c443266cc8c77ddefbfaa12ec013c87db4647bfa76353111c994b49e50a61702 - references/java-11-to-17.md: SHA-256 d63d4a0fc58089c2df342ecff6f76bdcb78ec116be265a4d1fd7c879af479d75 - references/java-17-to-21.md: SHA-256 24ee77f15c8ce2ba7a757b5202d19c9f6a4b3d7e9915f2a5bb4774087bb061d9 - references/java-21-to-25.md: SHA-256 2f558a84db94a9e88f879d0cedaf4538f9b9d3f89e791c5281a032e9af9e1b09 - references/upstream-sources.md: SHA-256 50b5684be6e8c820b466498ab7f5317932857f92f2168930926da50bc9fdc1fd If a file does not match, it changed since the listing was prepared: do not install it yet, tell me what you found and let me decide. 2. Read SKILL.md in full (and every other file in the folder) and tell me in plain words: what the skill does when used, which services it connects to, whether it reads or sends any personal information or keys, and anything that seems unusual. Stop on any red flag and tell me before going further. Confirm these points from the files: - The skill folder holds 5 files: SKILL.md plus four reference files in references/ (the three per version guides and the upstream sources list). There is no executable code of its own. - Nothing is sent anywhere during installation itself; the only download is the skill folder from GitHub at the pinned commit. - At use time the agent is told to fetch official documentation pages for the target Java version (openjdk.org, Oracle, Gradle and OpenRewrite docs) and prefer them over the skill when they conflict. Your project code is not uploaded by the skill. - The modernize-java plugin shown in SKILL.md is a separate Microsoft plugin installed through GitHub Copilot: it is optional, it is not part of this folder, and the skill works without it. 3. When I say "yes, install", install it as a skill: copy the whole folder into the agent's skills directory, in a folder named "java-upgrade", keeping every file (SKILL.md, references/java-11-to-17.md, references/java-17-to-21.md, references/java-21-to-25.md, references/upstream-sources.md). 4. Verify with no network calls: frontmatter valid, files in place. 5. Report what was installed, where, and what I still need to do myself (for example: sign in or create an account, provide any API key, or install any local tool named in the prerequisites; using the skill is a separate step that only starts when I ask for it, and every paid or authenticated use disclosed above happens only then). GitHub is optional: if I have a GitHub account or the gh CLI, you may use it; otherwise public access is fine. Never require it unless it's in the prerequisites above. Rules: don't touch anything outside the temp folder and the install target. If anything looks off, stop and ask me.