Avoid update maven project from deadlocking after...

@ConfigurationProperties quickfix

Author: kdvolder

eclipse-extensions/org.springframework.ide.eclipse.boot/src/org/springframework/ide/eclipse/boot/core/internal/MavenSpringBootProject.java

@@ -49,11 +49,14 @@
 import org.eclipse.core.resources.IContainer;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
+import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.core.runtime.Path;
+import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.SubMonitor;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.debug.core.DebugPlugin;
@@ -317,11 +320,26 @@ public void process(Document pom) {
 
 	@Override
 	public Job updateProjectConfiguration() {
-		Job job = new UpdateMavenProjectJob(new IProject[] {
-				getProject()
-		});
-		job.schedule();
-		return job;
+		//We wrap the UpdateMavenProjectJob in another job to avoid a race condition
+		//that causes a deadlock. The race condition is avoided by have the
+		//waitForWorkspaceLock wrapper which ensures that pending workspace jobs
+		//are finished before triggering maven project update.
+		//See: https://github.com/spring-projects/sts4/issues/780
+		Job waitForWorkspaceLock = new Job("Wait for for workspace") {
+			{
+				setRule(ResourcesPlugin.getWorkspace().getRuleFactory().buildRule());
+			}
+
+			@Override
+			protected IStatus run(IProgressMonitor arg0) {
+				Job job = new UpdateMavenProjectJob(new IProject[] {
+						getProject()
+				});
+				job.schedule();
+				return Status.OK_STATUS;
+			}
+		};
+		return waitForWorkspaceLock;
  	}
 
 	@Override