diff --git a/index.js b/index.js
index 582cfc2..0f95860 100644
--- a/index.js
+++ b/index.js
@@ -19,6 +19,7 @@ async function run() {
       rubyPrefix = await windows.downloadExtractAndSetPATH(ruby)
     } else {
       if (ruby.startsWith('jruby')) {
+        // Workaround for https://github.com/actions/virtual-environments/issues/242
         core.exportVariable('CLASSPATH', '')
       }
       rubyPrefix = await downloadAndExtract(platform, ruby)