diff --git a/core/src/main/java/hudson/PluginManager.java b/core/src/main/java/hudson/PluginManager.java
index 3b31735410..941cde4a88 100644
--- a/core/src/main/java/hudson/PluginManager.java
+++ b/core/src/main/java/hudson/PluginManager.java
@@ -93,6 +93,7 @@ import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.Future;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -738,16 +739,18 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
      * Prepares plugins for some expected XML configuration.
      * If the configuration (typically a job’s {@code config.xml})
      * needs some plugins to be installed (or updated), those jobs
-     * will be triggered. Requires {@link Jenkins#ADMINISTER}.
+     * will be triggered.
+     * Plugins are dynamically loaded if possible (see {@link hudson.model.UpdateSite.Plugin#deploy(boolean)}).
+     * Requires {@link Jenkins#ADMINISTER}.
      * @param configXml configuration that might be uploaded
-     * @return an empty list if all is well, else a list of jobs which must be completed before this configuration can be fully read
+     * @return an empty list if all is well, else a list of submitted jobs which must be completed before this configuration can be fully read
      * @throws IOException if loading or parsing the configuration failed
      * @see ItemGroupMixIn#createProjectFromXML
      * @see AbstractItem#updateByXml(javax.xml.transform.Source)
      * @see XStream2
      * @since XXX
      */
-    public List<UpdateCenter.UpdateCenterJob> prevalidateConfig(InputStream configXml) throws IOException {
+    public List<Future<UpdateCenter.UpdateCenterJob>> prevalidateConfig(InputStream configXml) throws IOException {
         Jenkins.getInstance().checkPermission(Jenkins.ADMINISTER);
         return Collections.emptyList(); // XXX
     }
diff --git a/test/src/test/java/hudson/PluginManagerTest.java b/test/src/test/java/hudson/PluginManagerTest.java
index b138b1d2f0..fd0ffedcce 100644
--- a/test/src/test/java/hudson/PluginManagerTest.java
+++ b/test/src/test/java/hudson/PluginManagerTest.java
@@ -23,11 +23,18 @@
  */
 package hudson;
 
+import com.gargoylesoftware.htmlunit.HttpMethod;
+import com.gargoylesoftware.htmlunit.Page;
+import com.gargoylesoftware.htmlunit.WebRequestSettings;
 import com.gargoylesoftware.htmlunit.html.HtmlForm;
 import com.gargoylesoftware.htmlunit.html.HtmlPage;
 import hudson.PluginManager.UberClassLoader;
 import hudson.model.Hudson;
+import hudson.model.UpdateCenter;
+import hudson.model.UpdateCenter.UpdateCenterJob;
+import hudson.model.UpdateSite;
 import hudson.scm.SubversionSCM;
+import hudson.util.PersistedList;
 import org.apache.commons.io.FileUtils;
 import org.jvnet.hudson.test.HudsonTestCase;
 import org.jvnet.hudson.test.Url;
@@ -37,6 +44,11 @@ import org.jvnet.hudson.test.recipes.WithPluginManager;
 import java.io.File;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Future;
+import org.apache.commons.io.IOUtils;
+import org.apache.tools.ant.filters.StringInputStream;
 
 /**
  * @author Kohsuke Kawaguchi
@@ -190,4 +202,35 @@ public class PluginManagerTest extends HudsonTestCase {
         Class c = jenkins.getPluginManager().uberClassLoader.loadClass("htmlpublisher.HtmlPublisher$DescriptorImpl");
         assertNotNull(jenkins.getDescriptorByType(c));
     }
+
+    public void testPrevalidateConfig() throws Exception {
+        PersistedList<UpdateSite> sites = jenkins.getUpdateCenter().getSites();
+        sites.clear();
+        URL url = PluginManagerTest.class.getResource("/plugins/tasks-update-center.json");
+        UpdateSite site = new UpdateSite(UpdateCenter.ID_DEFAULT, url.toString());
+        sites.add(site);
+        try {
+            UpdateSite.signatureCheck = false;
+            { // XXX pending UpdateSite.updateDirectly:
+                jenkins.setCrumbIssuer(null);
+                WebRequestSettings wrs = new WebRequestSettings(new URL(getURL(), "/updateCenter/byId/default/postBack"), HttpMethod.POST);
+                wrs.setRequestBody(IOUtils.toString(url.openStream()));
+                Page p = createWebClient().getPage(wrs);
+                assertEquals(/* FormValidation.OK */"<div/>", p.getWebResponse().getContentAsString());
+            }
+        } finally {
+            UpdateSite.signatureCheck = true;
+        }
+        assertNotNull(site.getData());
+        assertEquals(Collections.emptyList(), jenkins.getPluginManager().prevalidateConfig(new StringInputStream("<whatever><runant plugin=\"ant 1.1\"/></whatever>")));
+        assertNull(jenkins.getPluginManager().getPlugin("tasks"));
+        List<Future<UpdateCenterJob>> jobs = jenkins.getPluginManager().prevalidateConfig(new StringInputStream("<whatever><tasks plugin=\"tasks 2.23\"/></whatever>"));
+        assertEquals(1, jobs.size());
+        UpdateCenterJob job = jobs.get(0).get(); // blocks for completion
+        assertEquals("InstallationJob", job.getType());
+        UpdateCenter.InstallationJob ijob = (UpdateCenter.InstallationJob) job;
+        assertEquals("tasks", ijob.plugin.name);
+        assertNotNull(jenkins.getPluginManager().getPlugin("tasks"));
+    }
+
 }