When deploying you Xtend application to a different environment than your development environment you might encounter an error such as:
[ERROR] symbol: class Consumer
[ERROR] cannot find symbol
This error is caused by Xtend trying to use Java 8 features. It does so when your development machine runs Java 8.
For eclipse, you can fix this by using a Java 7 JDK under Window / Preferences / Java / Installed JREs. Then ‘Clean’ your project and all references to the Consumer class should be obliterated.
For Maven, you can find more information on this page.