[ https://issues.jboss.org/browse/JBIDE-17078?page=com.atlassian.jira.plugi... ] Alexey Kazakov commented on JBIDE-17078: ---------------------------------------- {quote}I should ensure that the WST validator is also added (or already there) when the JAX-RS nature is added,{quote} Yes, you should if you want to enable JAX-RS validation even for projects w/o WST validation builder (plain java projects for example) I suggest you to use org.jboss.tools.jst.web.WebModelPlugin.addNatureToProjectWithValidationSupport(IProject project, String builderId, String natureId) for adding JAX-RS nature/builder. It will add WST validation builder automatically if needed. {quote}I should trigger a project build if the WST validation was already present when the JAX-RS nature was added (and only in that case) ?{quote} Full build, yes. Incremental build won't help because it will trigger validation of the only changed .project file. BTW, we have the same problem with other our validators: CDI, JSF, Seam,... We do not re-build project when enabling our validators. -- This message was sent by Atlassian JIRA (v6.2.6#6264)