diff --git a/changelog.html b/changelog.html
index 20f1474320b9ea8767118d95b63da629a46d8880..8d6295ffe4bf32390ec21c46e655fedf0ddcaf0f 100644
--- a/changelog.html
+++ b/changelog.html
@@ -55,6 +55,12 @@ Upcoming changes</a>
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
 <ul class=image>
+  <li class=bug>
+    Fixed <tt>NoSuchFieldError: triggers</tt> with older Maven plugin
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-18677">issue 18677</a>)
+  <li class=rfe>
+    Added bytecode transformation driven compatibility ensurance mechanism
+    (<a href="https://groups.google.com/forum/#!topic/jenkinsci-dev/7qCClb36njo">discussion</a>)
   <li class=rfe>
     Improve search to locate items inside folders.
     (<a href="https://github.com/jenkinsci/jenkins/pull/848">pull request 848</a>)
diff --git a/core/pom.xml b/core/pom.xml
index 9cdcdb1a47b495acd42a9d9f6686a6c15d171e00..9e130a5ea51b365d2002b37ec26a9e2736af710e 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -214,6 +214,11 @@ THE SOFTWARE.
       <artifactId>annotation-indexer</artifactId>
       <version>1.4</version>
     </dependency>
+    <dependency>
+      <groupId>org.jenkins-ci</groupId>
+      <artifactId>bytecode-compatibility-transformer</artifactId>
+      <version>1.3</version>
+    </dependency>
     <dependency>
       <groupId>org.jvnet.hudson</groupId>
       <artifactId>task-reactor</artifactId>
diff --git a/core/src/main/java/hudson/ClassicPluginStrategy.java b/core/src/main/java/hudson/ClassicPluginStrategy.java
index 5f70486ddc92ad64043ff8d342e2d298e2d83797..e4d158128cf731d42d0bfd220e0fafdeb6e4ed0c 100644
--- a/core/src/main/java/hudson/ClassicPluginStrategy.java
+++ b/core/src/main/java/hudson/ClassicPluginStrategy.java
@@ -59,7 +59,6 @@ import java.io.IOException;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.net.URL;
-import java.net.URLClassLoader;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -223,19 +222,10 @@ public class ClassicPluginStrategy implements PluginStrategy {
                 return classLoader;
             }
         }
-        if(useAntClassLoader && !Closeable.class.isAssignableFrom(URLClassLoader.class)) {
-            // using AntClassLoader with Closeable so that we can predictably release jar files opened by URLClassLoader
-            AntClassLoader2 classLoader = new AntClassLoader2(parent);
-            classLoader.addPathFiles(paths);
-            return classLoader;
-        } else {
-            // Tom reported that AntClassLoader has a performance issue when Hudson keeps trying to load a class that doesn't exist,
-            // so providing a legacy URLClassLoader support, too
-            List<URL> urls = new ArrayList<URL>();
-            for (File path : paths)
-                urls.add(path.toURI().toURL());
-            return new URLClassLoader(urls.toArray(new URL[urls.size()]),parent);
-        }
+
+        AntClassLoader2 classLoader = new AntClassLoader2(parent);
+        classLoader.addPathFiles(paths);
+        return classLoader;
     }
 
     /**
@@ -652,7 +642,7 @@ public class ClassicPluginStrategy implements PluginStrategy {
      * {@link AntClassLoader} with a few methods exposed and {@link Closeable} support.
      * Deprecated as of Java 7, retained only for Java 5/6.
      */
-    private static final class AntClassLoader2 extends AntClassLoader implements Closeable {
+    private final class AntClassLoader2 extends AntClassLoader implements Closeable {
         private final Vector pathComponents;
 
         private AntClassLoader2(ClassLoader parent) {
@@ -669,6 +659,7 @@ public class ClassicPluginStrategy implements PluginStrategy {
             }
         }
 
+
         public void addPathFiles(Collection<File> paths) throws IOException {
             for (File f : paths)
                 addPathFile(f);
@@ -699,6 +690,11 @@ public class ClassicPluginStrategy implements PluginStrategy {
 
             return url;
         }
+
+        @Override
+        protected Class defineClassFromData(File container, byte[] classData, String classname) throws IOException {
+            return super.defineClassFromData(container, pluginManager.getCompatibilityTransformer().transform(classname,classData), classname);
+        }
     }
 
     public static boolean useAntClassLoader = Boolean.getBoolean(ClassicPluginStrategy.class.getName()+".useAntClassLoader");
diff --git a/core/src/main/java/hudson/PluginManager.java b/core/src/main/java/hudson/PluginManager.java
index 8bdb17ae89e08999ebc6686529e66d2cf112ad61..7ce9dea6d3456fbbab2306b7ad951265ae0215c8 100644
--- a/core/src/main/java/hudson/PluginManager.java
+++ b/core/src/main/java/hudson/PluginManager.java
@@ -59,6 +59,7 @@ import org.apache.commons.fileupload.servlet.ServletFileUpload;
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.logging.LogFactory;
+import org.jenkinsci.bytecode.Transformer;
 import org.jvnet.hudson.reactor.Executable;
 import org.jvnet.hudson.reactor.Reactor;
 import org.jvnet.hudson.reactor.ReactorException;
@@ -151,6 +152,8 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
     // and load plugin-contributed classes.
     public final ClassLoader uberClassLoader = new UberClassLoader();
 
+    private final Transformer compatibilityTransformer = new Transformer();
+
     /**
      * Once plugin is uploaded, this flag becomes true.
      * This is used to report a message that Jenkins needs to be restarted
@@ -179,6 +182,17 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
             rootDir.mkdirs();
         
         strategy = createPluginStrategy();
+
+        // load up rules for the core first
+        try {
+            compatibilityTransformer.loadRules(getClass().getClassLoader());
+        } catch (IOException e) {
+            LOGGER.log(Level.WARNING, "Failed to load compatibility rewrite rules",e);
+        }
+    }
+
+    public Transformer getCompatibilityTransformer() {
+        return compatibilityTransformer;
     }
 
     public Api getApi() {
@@ -301,6 +315,13 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
                                 }
                             });
 
+                            // Let's see for a while until we open this functionality up to plugins
+//                            g.followedBy().attains(PLUGINS_LISTED).add("Load compatibility rules", new Executable() {
+//                                public void run(Reactor reactor) throws Exception {
+//                                    compatibilityTransformer.loadRules(uberClassLoader);
+//                                }
+//                            });
+
                             session.addAll(g.discoverTasks(session));
 
                             pluginListed = true; // technically speaking this is still too early, as at this point tasks are merely scheduled, not necessarily executed.
diff --git a/core/src/main/java/hudson/model/AbstractProject.java b/core/src/main/java/hudson/model/AbstractProject.java
index 515dee2d72fc1d71dae36361538ab6ec6a2d3ce9..6a5cc387f54c039e38204e39c2f12f4a0664e000 100644
--- a/core/src/main/java/hudson/model/AbstractProject.java
+++ b/core/src/main/java/hudson/model/AbstractProject.java
@@ -95,6 +95,7 @@ import net.sf.json.JSONObject;
 import org.acegisecurity.Authentication;
 import org.acegisecurity.context.SecurityContext;
 import org.acegisecurity.context.SecurityContextHolder;
+import org.jenkinsci.bytecode.AdaptField;
 import org.kohsuke.accmod.Restricted;
 import org.kohsuke.accmod.restrictions.NoExternalUse;
 import org.kohsuke.args4j.Argument;
@@ -242,6 +243,7 @@ public abstract class AbstractProject<P extends AbstractProject<P,R>,R extends A
     /**
      * List of all {@link Trigger}s for this project.
      */
+    @AdaptField(was=List.class)
     protected volatile DescribableList<Trigger<?>,TriggerDescriptor> triggers = new DescribableList<Trigger<?>,TriggerDescriptor>(this);
     private static final AtomicReferenceFieldUpdater<AbstractProject,DescribableList> triggersUpdater
             = AtomicReferenceFieldUpdater.newUpdater(AbstractProject.class,DescribableList.class,"triggers");
diff --git a/pom.xml b/pom.xml
index b552aac8878cd3fdc49be3f081f14b8cd2f89a1a..02e96ce8154f10dfccd9560f21501c801fc63baa 100644
--- a/pom.xml
+++ b/pom.xml
@@ -174,7 +174,7 @@ THE SOFTWARE.
       <dependency>
         <groupId>org.jenkins-ci.main</groupId>
         <artifactId>remoting</artifactId>
-        <version>2.31</version>
+        <version>2.32</version>
       </dependency>
 
       <dependency>