org.jboss.tools.common.validation.JBTValidationException
	at org.jboss.tools.common.validation.ValidatorManager.validateInJob(ValidatorManager.java:101)
	at org.eclipse.wst.validation.internal.operations.ValidatorJob.run(ValidatorJob.java:78)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
Caused by: java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
	at java.util.HashMap$KeyIterator.next(HashMap.java:828)
	at org.jboss.tools.common.el.core.resolver.ELResolverFactoryManager.getResolvers(ELResolverFactoryManager.java:117)
	at org.jboss.tools.jst.web.kb.internal.validation.ELValidator.init(ELValidator.java:141)
	at org.jboss.tools.jst.web.kb.internal.validation.ELValidator.validateAll(ELValidator.java:217)
	at org.jboss.tools.common.validation.ValidatorManager.validateAll(ValidatorManager.java:131)
	at org.jboss.tools.common.validation.ValidatorManager.validateInJob(ValidatorManager.java:84)
	... 2 more