将BinTray Maven构件同步至JCenter时遇校验错误求助

Let’s tackle your JCenter sync issues head-on—here’s what you can do to get to the bottom of those vague error messages, and whether JCenter’s validation logic might be causing problems.

Getting More Detailed Error Information #

The generic messages like "corrupted JAR" or "missing sources" don’t give enough context, so try these steps to uncover specifics:

• Check BinTray’s Sync Logs: Navigate to your artifact in BinTray, go to the "Sync" tab, and look for the full logs of the failed sync attempts. These logs often include granular details like which exact file failed validation, or a specific rule that was violated.
• Re-trigger Sync with Verbose Feedback: Use JCenter’s web interface to manually initiate a sync for the problematic artifacts. Sometimes the automated sync process suppresses detailed errors, but a manual trigger might expose more info.
• Validate Artifacts Locally: Even though you can read the JARs, run these checks to rule out hidden issues:
  • Use jar tf <your-jar-file> to list all contents and confirm no unexpected missing files or corrupt entries.
  • Compare the file hashes (MD5/SHA1) of your local downloads with the ones displayed on BinTray—this ensures the file wasn’t corrupted during upload to BinTray.
  • Run mvn verify -DskipTests on your project to let Maven’s built-in validation tools check for compliance with standard Maven artifact rules.

Is JCenter’s Validation Logic Flawed? #

JCenter does have stricter (and sometimes less-documented) validation rules compared to direct Maven Central syncs, which can lead to false positives or confusing errors. Here are some common gotchas to check:

• Nested JARs in the Main Artifact: You mentioned your main JAR contains other JARs and class files. While Maven technically allows this, JCenter’s validation might flag this as non-standard—most Maven artifacts don’t embed other JARs (they use dependency declarations instead). This could be triggering the "corrupted JAR" or "unverifiable JAR" errors.
• Source JAR Coverage: JCenter likely checks that every class file in your main JAR has a corresponding .java file in the sources JAR, with identical directory structure. If your main JAR includes nested JARs with class files, JCenter might be expecting those nested classes to have sources in your sources JAR too—something that’s not typical if those nested JARs are external dependencies.
• File Permissions: Ensure your artifacts on BinTray have world-readable permissions (chmod 644). If permissions are restricted, JCenter’s validation service might not be able to read the files properly, leading to "unverifiable" errors.
• Hidden Manifest Issues: Check the MANIFEST.MF in your main JAR for missing or malformed entries. JCenter might enforce specific manifest attributes that aren’t explicitly documented.

Alternative Fixes (Without Putting Sources in the Main JAR) #

Since embedding sources in the main JAR isn’t an ideal solution, try these workarounds:

• Replace Nested JARs with Dependencies: If your main JAR includes external JARs, refactor your project to declare them as regular Maven dependencies instead of embedding them. Use the maven-dependency-plugin to manage dependencies, and rebuild your artifact.
• Align Source JAR with Main JAR Contents: If the issue is missing sources for nested classes, extract those classes into your project’s source tree (if they’re your code) or ensure the sources for those nested JARs are included in your sources JAR.
• Contact JCenter Support: If all local checks pass and you’re still seeing errors, reach out to JCenter’s support team with details about your artifact (name, version, BinTray link, local validation results). They can investigate if the issue is due to a bug or an undocumented rule in their validation system.

内容的提问来源于stack exchange，提问作者Nigel Jones