Can't use 1.8 jar as static file

[Ricardo Meneghin Filho]

I'm trying to use a jar with Java 8 source but i receive the following error when trying to update my app:

Unable to update app: Class file is Java 8 but max supported is Java 7

I don't intend to use the classes inside it as servlets, and i haven't mapped them to servlets, so gae should'nt complain about this. 

How can i fix this?

[Nick (Cloud Platform Support)]

The place to post a question like this would be stackoverflow or the public issue tracker. This forum isn't mean for specific-issue technical support, and if such an issue is mentioned, it should be supplementary to a post which is centered around discussing more generally with the wider community of developers about the platform. 

The runtime for Java on App Engine is based on Java 7, so this error makes some sense. Although if you don't reference this file, is it still in some kind of /lib folder? The information to include when you post to one of the locations mentioned above would include the answer to this investigative question, along with a tree of your project, a description of the jar, the deployment descriptor files (appengine-web.xml, web.xml, app.yaml, etc.) and some more full logs output.