Concurrency issue when loading plugins

[Konijnendijk]

Summary

In recent releases Xill switched to the reflections library for classpath scanning to search for constructs in plugins. Internally, this library caches jar files, which causes problems when loading plugins for multiple Xill environments at the same time. This is a particularly big problem for XDE.

The issue is described here: ronmamo/reflections#81.

Steps to reproduce

• Start an XDE instance and deploy the xill-connector-suite
• Call the GetEntity robot multiple times at once (24 in my case)
• Observe the same stack trace as described at the issue mentioned above

Possible fixes

1. This issue is fixed in the latest reflections version, but this version is not yet released. Switch to it when a new release is made.
2. Switch to a different library, e.g.: https://github.com/lukehutch/fast-classpath-scanner/