jenkinsci/jenkins · error · IllegalArgumentException

JAR lacks a manifest

Error message

JAR lacks a manifest

What it means

Error "JAR lacks a manifest" thrown in jenkinsci/jenkins.

Source

Thrown at core/src/main/java/hudson/cli/InstallPluginCommand.java:180

            throw new AbortException("Error occurred, see previous output.");
        }

        if (restart)
            h.safeRestart();
        return 0; // all success
    }

    private static File getTmpFile() throws Exception {
        return File.createTempFile("download", ".jpi.tmp", Jenkins.get().getPluginManager().rootDir);
    }

    private static File moveToFinalLocation(File tmpFile) throws Exception {
        String pluginName;
        try (JarFile jf = new JarFile(tmpFile)) {
            Manifest mf = jf.getManifest();
            if (mf == null) {
                throw new IllegalArgumentException("JAR lacks a manifest");
            }
            pluginName = mf.getMainAttributes().getValue("Short-Name");
        }
        if (pluginName == null) {
            throw new IllegalArgumentException("JAR manifest lacks a Short-Name attribute and so does not look like a plugin");
        }
        File target = new File(Jenkins.get().getPluginManager().rootDir, pluginName + ".jpi");
        Files.move(tmpFile.toPath(), target.toPath(), StandardCopyOption.REPLACE_EXISTING, StandardCopyOption.ATOMIC_MOVE);
        return target;
    }
}

View on GitHub (pinned to 2e228ff40b)

Solutions

1. Verify the file is a valid JAR/HPI plugin archive, not an HTML error page or corrupted download.
2. Re-download the plugin from the Jenkins update center or plugins.jenkins.io.
3. Inspect the archive with 'jar tf <file>' to confirm it is a well-formed JAR.

When it happens

Trigger: Raised when the install-plugin CLI command is given a local file that is not a valid JAR/HPI (no META-INF/MANIFEST.MF).

Common situations: See trigger scenarios.

AI-assisted analysis of jenkinsci/jenkins@2e228ff40b (2026-08-14). Data as JSON: /api/errors/cdf799a0edac58a6. Report an issue: GitHub.