diff --git a/core/src/main/java/hudson/matrix/MatrixProject.java b/core/src/main/java/hudson/matrix/MatrixProject.java
index 2c05c72394..6390db6839 100644
--- a/core/src/main/java/hudson/matrix/MatrixProject.java
+++ b/core/src/main/java/hudson/matrix/MatrixProject.java
@@ -66,9 +66,10 @@ import hudson.util.CopyOnWriteMap;
 import hudson.util.DescribableList;
 import hudson.util.FormValidation;
 import hudson.util.FormValidation.Kind;
-import jenkins.model.ModelObjectWithChildren;
 import jenkins.scm.SCMCheckoutStrategyDescriptor;
 import net.sf.json.JSONObject;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 import org.kohsuke.stapler.HttpResponse;
 import org.kohsuke.stapler.StaplerRequest;
 import org.kohsuke.stapler.StaplerResponse;
@@ -897,9 +898,14 @@ public class MatrixProject extends AbstractProject<MatrixProject,MatrixBuild> im
     }
 
     public DescriptorImpl getDescriptor() {
-        return DESCRIPTOR;
+        return (DescriptorImpl)Jenkins.getInstance().getDescriptorOrDie(getClass());
     }
 
+    /**
+     * Descriptor is instantiated as a field purely for backward compatibility.
+     * Do not do this in your code. Put @Extension on your DescriptorImpl class instead.
+     */
+    @Restricted(NoExternalUse.class)
     @Extension
     public static final DescriptorImpl DESCRIPTOR = new DescriptorImpl();
 
diff --git a/core/src/main/java/hudson/model/FreeStyleProject.java b/core/src/main/java/hudson/model/FreeStyleProject.java
index 8eacc0ae75..11ce99a30b 100644
--- a/core/src/main/java/hudson/model/FreeStyleProject.java
+++ b/core/src/main/java/hudson/model/FreeStyleProject.java
@@ -25,6 +25,8 @@ package hudson.model;
 
 import hudson.Extension;
 import jenkins.model.Jenkins;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 
 /**
  * Free-style software project.
@@ -50,9 +52,14 @@ public class FreeStyleProject extends Project<FreeStyleProject,FreeStyleBuild> i
     }
 
     public DescriptorImpl getDescriptor() {
-        return DESCRIPTOR;
+        return (DescriptorImpl)Jenkins.getInstance().getDescriptorOrDie(getClass());
     }
 
+    /**
+     * Descriptor is instantiated as a field purely for backward compatibility.
+     * Do not do this in your code. Put @Extension on your DescriptorImpl class instead.
+     */
+    @Restricted(NoExternalUse.class)
     @Extension(ordinal=1000)
     public static final DescriptorImpl DESCRIPTOR = new DescriptorImpl();
 
diff --git a/maven-plugin/src/main/java/hudson/maven/MavenModuleSet.java b/maven-plugin/src/main/java/hudson/maven/MavenModuleSet.java
index 86d8a32d5a..d297541c63 100644
--- a/maven-plugin/src/main/java/hudson/maven/MavenModuleSet.java
+++ b/maven-plugin/src/main/java/hudson/maven/MavenModuleSet.java
@@ -33,7 +33,6 @@ import hudson.Functions;
 import hudson.Indenter;
 import hudson.Plugin;
 import hudson.Util;
-import hudson.matrix.MatrixConfiguration;
 import hudson.maven.local_repo.DefaultLocalRepositoryLocator;
 import hudson.maven.local_repo.LocalRepositoryLocator;
 import hudson.maven.local_repo.PerJobLocalRepositoryLocator;
@@ -107,6 +106,8 @@ import org.apache.commons.lang.StringUtils;
 import org.apache.commons.lang.math.NumberUtils;
 import org.apache.maven.model.building.ModelBuildingRequest;
 import hudson.tasks.Mailer;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 import org.kohsuke.stapler.HttpResponse;
 import org.kohsuke.stapler.HttpResponses;
 import org.kohsuke.stapler.QueryParameter;
@@ -1040,7 +1041,7 @@ public class MavenModuleSet extends AbstractMavenProject<MavenModuleSet,MavenMod
             return mavenOpts.replaceAll("[\t\r\n]+"," ");
         }
         else {
-            String globalOpts = DESCRIPTOR.getGlobalMavenOpts();
+            String globalOpts = getDescriptor().getGlobalMavenOpts();
             if (globalOpts!=null) {
                 return globalOpts.replaceAll("[\t\r\n]+"," ");
             }
@@ -1062,7 +1063,7 @@ public class MavenModuleSet extends AbstractMavenProject<MavenModuleSet,MavenMod
      * If null, we pick any random Maven installation.
      */
     public MavenInstallation getMaven() {
-        MavenInstallation[] installations = DESCRIPTOR.getMavenDescriptor().getInstallations();
+        MavenInstallation[] installations = getDescriptor().getMavenDescriptor().getInstallations();
         for( MavenInstallation i : installations) {
             if(mavenName==null || i.getName().equals(mavenName))
                 return i;
@@ -1201,9 +1202,14 @@ public class MavenModuleSet extends AbstractMavenProject<MavenModuleSet,MavenMod
     }
 
     public DescriptorImpl getDescriptor() {
-        return DESCRIPTOR;
+        return (DescriptorImpl)Jenkins.getInstance().getDescriptorOrDie(getClass());
     }
 
+    /**
+     * Descriptor is instantiated as a field purely for backward compatibility.
+     * Do not do this in your code. Put @Extension on your DescriptorImpl class instead.
+     */
+    @Restricted(NoExternalUse.class)
     @Extension(ordinal=900)
     public static final DescriptorImpl DESCRIPTOR = new DescriptorImpl();
 
diff --git a/test/src/test/java/hudson/model/JobPropertyTest.java b/test/src/test/java/hudson/model/JobPropertyTest.java
index fb098bea31..955c981a8b 100644
--- a/test/src/test/java/hudson/model/JobPropertyTest.java
+++ b/test/src/test/java/hudson/model/JobPropertyTest.java
@@ -42,16 +42,16 @@ public class JobPropertyTest extends HudsonTestCase {
      */
     @Bug(2398)
     public void testJobPropertySummaryIsShownInMavenModuleSetIndexPage() throws Exception {
-        assertJobPropertySummaryIsShownInIndexPage(MavenModuleSet.DESCRIPTOR);
+        assertJobPropertySummaryIsShownInIndexPage(MavenModuleSet.class);
     }
     public void testJobPropertySummaryIsShownInMatrixProjectIndexPage() throws Exception {
-        assertJobPropertySummaryIsShownInIndexPage(MatrixProject.DESCRIPTOR);
+        assertJobPropertySummaryIsShownInIndexPage(MatrixProject.class);
     }
     public void testJobPropertySummaryIsShownInFreeStyleProjectIndexPage() throws Exception {
-        assertJobPropertySummaryIsShownInIndexPage(FreeStyleProject.DESCRIPTOR);
+        assertJobPropertySummaryIsShownInIndexPage(FreeStyleProject.class);
     }
 
-    private void assertJobPropertySummaryIsShownInIndexPage(TopLevelItemDescriptor type) throws Exception {
+    private void assertJobPropertySummaryIsShownInIndexPage(Class<? extends TopLevelItem> type) throws Exception {
         JobPropertyImpl jp = new JobPropertyImpl("NeedleInPage");
         Job<?,?> project = (Job<?, ?>) jenkins.createProject(type, "job-test-case");
         project.addProperty(jp);
diff --git a/test/src/test/java/hudson/model/labels/LabelExpressionTest.java b/test/src/test/java/hudson/model/labels/LabelExpressionTest.java
index 60c85d80a8..f2df9b9673 100644
--- a/test/src/test/java/hudson/model/labels/LabelExpressionTest.java
+++ b/test/src/test/java/hudson/model/labels/LabelExpressionTest.java
@@ -30,6 +30,7 @@ import hudson.model.AbstractProject;
 import hudson.model.BuildListener;
 import hudson.model.FreeStyleBuild;
 import hudson.model.FreeStyleProject;
+import hudson.model.FreeStyleProject.DescriptorImpl;
 import hudson.model.Label;
 import hudson.model.Node.Mode;
 import hudson.slaves.DumbSlave;
@@ -228,13 +229,15 @@ public class LabelExpressionTest extends HudsonTestCase {
     public void testFormValidation() throws Exception {
         executeOnServer(new Callable<Object>() {
             public Object call() throws Exception {
+                DescriptorImpl d = jenkins.getDescriptorByType(DescriptorImpl.class);
+
                 Label l = jenkins.getLabel("foo");
                 DumbSlave s = createSlave(l);
-                String msg = FreeStyleProject.DESCRIPTOR.doCheckAssignedLabelString("goo").renderHtml();
+                String msg = d.doCheckAssignedLabelString("goo").renderHtml();
                 assertTrue(msg.contains("foo"));
                 assertTrue(msg.contains("goo"));
 
-                msg = FreeStyleProject.DESCRIPTOR.doCheckAssignedLabelString("master && goo").renderHtml();
+                msg = d.doCheckAssignedLabelString("master && goo").renderHtml();
                 assertTrue(msg.contains("foo"));
                 assertTrue(msg.contains("goo"));
                 return null;