as per title, a clean and build of a jar-format project fails silently, the resulting editor throws an exception (below). work-around by building ctree format first (not cleaning) and then switching to build the jar. no obvious errors during build.

org.metaborg.core.MetaborgException: Creating outline failed
	at org.metaborg.spoofax.core.outline.OutlineService.outline(OutlineService.java:80) ~[org.metaborg.spoofax.core_2.0.0.beta1.jar:na]
	at org.metaborg.spoofax.core.outline.OutlineService.outline(OutlineService.java:1) ~[org.metaborg.spoofax.core_2.0.0.beta1.jar:na]
	at org.metaborg.spoofax.eclipse.editor.EditorUpdateJob.outline(EditorUpdateJob.java:319) ~[org.metaborg.spoofax.eclipse_2.0.0.beta1.jar:na]
	at org.metaborg.spoofax.eclipse.editor.EditorUpdateJob.update(EditorUpdateJob.java:223) ~[org.metaborg.spoofax.eclipse_2.0.0.beta1.jar:na]
	at org.metaborg.spoofax.eclipse.editor.EditorUpdateJob.run(EditorUpdateJob.java:130) ~[org.metaborg.spoofax.eclipse_2.0.0.beta1.jar:na]
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55) [org.eclipse.core.jobs_3.7.0.v20150330-2103.jar:na]
Caused by: org.metaborg.core.MetaborgException: Invoking Stratego strategy editor-outline failed, strategy is undefined
	at org.metaborg.spoofax.core.stratego.StrategoCommon.handleException(StrategoCommon.java:132) ~[org.metaborg.spoofax.core_2.0.0.beta1.jar:na]
	at org.metaborg.spoofax.core.stratego.StrategoCommon.invoke(StrategoCommon.java:84) ~[org.metaborg.spoofax.core_2.0.0.beta1.jar:na]
	at org.metaborg.spoofax.core.outline.OutlineService.outline(OutlineService.java:73) ~[org.metaborg.spoofax.core_2.0.0.beta1.jar:na]
	... 5 common frames omitted
Caused by: org.spoofax.interpreter.core.UndefinedStrategyException: Definition 'editor-outline' not found
	at org.spoofax.interpreter.core.Interpreter.invoke(Interpreter.java:79) ~[org.spoofax.interpreter.core_2.0.0.beta1.jar:na]
	at org.strategoxt.HybridInterpreter.invoke(HybridInterpreter.java:442) ~[org.strategoxt.strj_2.0.0.beta1/:na]
	at org.metaborg.spoofax.core.stratego.StrategoCommon.invoke(StrategoCommon.java:78) ~[org.metaborg.spoofax.core_2.0.0.beta1.jar:na]
	... 6 common frames omitted

Submitted by Seyyed Shah on 1 July 2016 at 16:35

In the future, please format exceptions like:

exception

so they are readable.

About the issue, it could be that your Java files are not being compiled properly. Can you try right clicking the project, choosing Maven -> Update, and updating the project? Make sure to rebuild if after that.

Thanks, the maven update seems to resolve the issue.