diff --git a/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionComponentAdapter.java b/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionComponentAdapter.java
index 7d231b181587..49b5f4701783 100644
--- a/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionComponentAdapter.java
+++ b/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionComponentAdapter.java
@@ -47,13 +47,6 @@ public class ExtensionComponentAdapter implements LoadingOrder.Orderable, Assign
     myOrder = order;
   }
 
-  public ExtensionComponentAdapter(@NotNull String implementationClassName,
-                                   @Nullable Element extensionElement,
-                                   PicoContainer container,
-                                   PluginDescriptor pluginDescriptor) {
-    this(implementationClassName, container, pluginDescriptor, null, LoadingOrder.ANY, extensionElement);
-  }
-
   @Override
   public Object getComponentKey() {
     return this;
@@ -66,21 +59,22 @@ public class ExtensionComponentAdapter implements LoadingOrder.Orderable, Assign
 
   @Override
   public Object getComponentInstance(final PicoContainer container) throws PicoException, ProcessCanceledException {
-    if (myComponentInstance == null) {
+    Object instance = myComponentInstance;
+    if (instance == null) {
       try {
         Class impl = loadImplementationClass();
-        Object componentInstance = new CachingConstructorInjectionComponentAdapter(getComponentKey(), impl, null, true).getComponentInstance(container);
+        instance = new CachingConstructorInjectionComponentAdapter(getComponentKey(), impl, null, true).getComponentInstance(container);
 
         if (myExtensionElement != null) {
           try {
-            XmlSerializer.deserializeInto(componentInstance, myExtensionElement);
+            XmlSerializer.deserializeInto(instance, myExtensionElement);
           }
           catch (Exception e) {
             throw new PicoInitializationException(e);
           }
         }
 
-        myComponentInstance = componentInstance;
+        myComponentInstance = instance;
       }
       catch (ProcessCanceledException e) {
         throw e;
@@ -90,13 +84,13 @@ public class ExtensionComponentAdapter implements LoadingOrder.Orderable, Assign
         throw new PicoPluginExtensionInitializationException(t.getMessage(), t, pluginId);
       }
 
-      if (myComponentInstance instanceof PluginAware) {
-        PluginAware pluginAware = (PluginAware)myComponentInstance;
+      if (instance instanceof PluginAware) {
+        PluginAware pluginAware = (PluginAware)instance;
         pluginAware.setPluginDescriptor(myPluginDescriptor);
       }
     }
 
-    return myComponentInstance;
+    return instance;
   }
 
   @Override
@@ -162,8 +156,8 @@ public class ExtensionComponentAdapter implements LoadingOrder.Orderable, Assign
     return myNotificationSent;
   }
 
-  void setNotificationSent(boolean notificationSent) {
-    myNotificationSent = notificationSent;
+  void setNotificationSent() {
+    myNotificationSent = true;
   }
 
   @Override
diff --git a/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionPointImpl.java b/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionPointImpl.java
index abdbfac62398..2715d9597c9b 100644
--- a/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionPointImpl.java
+++ b/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionPointImpl.java
@@ -10,6 +10,7 @@ import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Disposer;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.containers.ContainerUtil;
+import com.intellij.util.containers.OpenTHashSet;
 import com.intellij.util.containers.StringInterner;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -152,7 +153,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
         }
 
         notifyListenersOnAdd(extension, adapter.getPluginDescriptor());
-        adapter.setNotificationSent(true);
+        adapter.setNotificationSent();
       }
     }
   }
@@ -199,9 +200,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
       //noinspection unchecked
       return (T[])Array.newInstance(getExtensionClass(), 0);
     }
-    else {
-      return myExtensionsCacheAsArray.clone();
-    }
+    return myExtensionsCacheAsArray.clone();
   }
 
   @NotNull
@@ -243,6 +242,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
       myExtensionAdapters = new LinkedHashSet<>(adapters);
 
       Set<ExtensionComponentAdapter> loaded = ContainerUtil.newHashOrEmptySet(myLoadedAdapters);
+      OpenTHashSet<T> duplicates = new OpenTHashSet<>(adapters.size());
 
       myLoadedAdapters = Collections.emptyList();
       boolean errorHappened = false;
@@ -254,11 +254,12 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
             errorHappened = true;
             LOG.error("null extension in: " + adapter + ";\ngetExtensionClass(): " + getExtensionClass() + ";\n" );
           }
-          if (i > 0 && extension == result[i - 1]) {
+          if (!duplicates.add(extension)) {
             errorHappened = true;
+            T duplicate = duplicates.get(extension);
             LOG.error("Duplicate extension found: " + extension + "; " +
-                      " Adapter:      " + adapter + ";\n" +
-                      " Prev adapter: " + adapters.get(i-1) + ";\n" +
+                      " Prev extension: " + duplicate + ";\n" +
+                      " Adapter:        " + adapter + ";\n" +
                       " getExtensionClass(): " + getExtensionClass() + ";\n" +
                       " result:" + Arrays.asList(result));
           }
@@ -268,6 +269,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
             continue;
           }
           result[i] = extension;
+
           registerExtension(extension, adapter, myLoadedAdapters.size(), !loaded.contains(adapter));
         }
         catch (ProcessCanceledException e) {
@@ -331,7 +333,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
   }
 
   @Override
-  public void unregisterExtension(@NotNull Class<? extends T> extensionClass) {
+  public synchronized void unregisterExtension(@NotNull Class<? extends T> extensionClass) {
     for (ExtensionComponentAdapter adapter : ContainerUtil.concat(myExtensionAdapters, myLoadedAdapters)) {
       if (adapter.getAssignableToClassName().equals(extensionClass.getCanonicalName())) {
         unregisterExtensionAdapter(adapter);
@@ -479,6 +481,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
     return extensionClass;
   }
 
+  @Override
   public String toString() {
     return getName();
   }
@@ -528,7 +531,7 @@ public final class ExtensionPointImpl<T> implements ExtensionPoint<T> {
     private final LoadingOrder myLoadingOrder;
 
     private ObjectComponentAdapter(@NotNull Object extension, @NotNull LoadingOrder loadingOrder) {
-      super(extension.getClass().getName(), null, null, null);
+      super(extension.getClass().getName(), null, null, null, LoadingOrder.ANY, null);
       myExtension = extension;
       myLoadingOrder = loadingOrder;
     }
diff --git a/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionsAreaImpl.java b/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionsAreaImpl.java
index bcee0c07368f..278681924b0d 100644
--- a/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionsAreaImpl.java
+++ b/platform/extensions/src/com/intellij/openapi/extensions/impl/ExtensionsAreaImpl.java
@@ -144,10 +144,6 @@ public class ExtensionsAreaImpl implements ExtensionsArea {
     registerExtensionPoint(epName, className, pluginDescriptor, kind);
   }
 
-  public void registerExtension(@NotNull final String pluginName, @NotNull final Element extensionElement) {
-    registerExtension(new DefaultPluginDescriptor(PluginId.getId(pluginName)), extensionElement, null);
-  }
-
   @Override
   public void registerExtension(@NotNull final PluginDescriptor pluginDescriptor, @NotNull final Element extensionElement, String extensionNs) {
     String epName = extractEPName(extensionElement, extensionNs);
diff --git a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionComponentAdapterTest.java b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionComponentAdapterTest.java
index 143fb898ab51..f606c36bcf85 100644
--- a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionComponentAdapterTest.java
+++ b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionComponentAdapterTest.java
@@ -33,7 +33,7 @@ public class ExtensionComponentAdapterTest {
     Element element = JDOMUtil.load("<bean implementation=\"123\"/>");
     DefaultPicoContainer container = new DefaultPicoContainer();
     DefaultPluginDescriptor descriptor = new DefaultPluginDescriptor("test");
-    new ExtensionComponentAdapter(name, element, container, descriptor).getComponentInstance(container);
+    new ExtensionComponentAdapter(name, container, descriptor, null, LoadingOrder.ANY, element).getComponentInstance(container);
   }
 
   @NotNull
diff --git a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionPointImplTest.java b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionPointImplTest.java
index f2363240e9c7..6c15372200b3 100644
--- a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionPointImplTest.java
+++ b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionPointImplTest.java
@@ -262,7 +262,7 @@ public class ExtensionPointImplTest {
     private boolean myFire;
 
     MyShootingComponentAdapter(@NotNull String implementationClass) {
-      super(implementationClass, null, new DefaultPicoContainer(), new DefaultPluginDescriptor("test"));
+      super(implementationClass, new DefaultPicoContainer(), new DefaultPluginDescriptor("test"), null, LoadingOrder.ANY, null);
     }
 
     public void setFire(boolean fire) {
diff --git a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsComplexTest.java b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsComplexTest.java
index 59ffe6c60479..e0659abb3b40 100644
--- a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsComplexTest.java
+++ b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsComplexTest.java
@@ -110,7 +110,7 @@ public class ExtensionsComplexTest {
   private static void initExtensions(@NonNls String data, AreaInstance instance) throws IOException, JDOMException {
     final Element element = JDOMUtil.load(data);
     for (final Element child : element.getChildren()) {
-      ((ExtensionsAreaImpl)Extensions.getArea(instance)).registerExtension(element.getNamespaceURI(), child);
+      ExtensionsImplTest.registerExtension(((ExtensionsAreaImpl)Extensions.getArea(instance)), element.getNamespaceURI(), child);
     }
   }
 
diff --git a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsImplTest.java b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsImplTest.java
index 795133a50861..99297014ac6d 100644
--- a/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsImplTest.java
+++ b/platform/extensions/testSrc/com/intellij/openapi/extensions/impl/ExtensionsImplTest.java
@@ -3,6 +3,7 @@ package com.intellij.openapi.extensions.impl;
 
 import com.intellij.openapi.extensions.*;
 import com.intellij.openapi.util.JDOMUtil;
+import org.jdom.Element;
 import org.jdom.JDOMException;
 import org.jetbrains.annotations.NotNull;
 import org.junit.Test;
@@ -156,11 +157,11 @@ public class ExtensionsImplTest {
   public void testExtensionsNamespaces() throws IOException, JDOMException {
     ExtensionsAreaImpl extensionsArea = new ExtensionsAreaImpl(new DefaultPicoContainer());
     extensionsArea.registerExtensionPoint("plugin.ep1", TestExtensionClassOne.class.getName(), ExtensionPoint.Kind.BEAN_CLASS);
-    extensionsArea.registerExtension("plugin", JDOMUtil.load(
+    registerExtension(extensionsArea, "plugin", JDOMUtil.load(
         "<plugin:ep1 xmlns:plugin=\"plugin\" order=\"LAST\"><text>3</text></plugin:ep1>"));
-    extensionsArea.registerExtension("plugin", JDOMUtil.load(
+    registerExtension(extensionsArea, "plugin", JDOMUtil.load(
         "<ep1 xmlns=\"plugin\" order=\"FIRST\"><text>1</text></ep1>"));
-    extensionsArea.registerExtension("plugin", JDOMUtil.load(
+    registerExtension(extensionsArea, "plugin", JDOMUtil.load(
         "<extension point=\"plugin.ep1\"><text>2</text></extension>"));
     ExtensionPoint extensionPoint = extensionsArea.getExtensionPoint("plugin.ep1");
     TestExtensionClassOne[] extensions = (TestExtensionClassOne[]) extensionPoint.getExtensions();
@@ -174,11 +175,11 @@ public class ExtensionsImplTest {
   public void testExtensionsWithOrdering() throws IOException, JDOMException {
     ExtensionsAreaImpl extensionsArea = new ExtensionsAreaImpl(new DefaultPicoContainer());
     extensionsArea.registerExtensionPoint("ep1", TestExtensionClassOne.class.getName(), ExtensionPoint.Kind.BEAN_CLASS);
-    extensionsArea.registerExtension("", JDOMUtil.load(
+    registerExtension(extensionsArea, "", JDOMUtil.load(
         "<extension point=\"ep1\" order=\"LAST\"><text>3</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load(
+    registerExtension(extensionsArea, "", JDOMUtil.load(
         "<extension point=\"ep1\" order=\"FIRST\"><text>1</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load(
+    registerExtension(extensionsArea, "", JDOMUtil.load(
         "<extension point=\"ep1\"><text>2</text></extension>"));
     ExtensionPoint extensionPoint = extensionsArea.getExtensionPoint("ep1");
     TestExtensionClassOne[] extensions = (TestExtensionClassOne[]) extensionPoint.getExtensions();
@@ -192,9 +193,9 @@ public class ExtensionsImplTest {
   public void testExtensionsWithOrderingUpdate() throws IOException, JDOMException {
     ExtensionsAreaImpl extensionsArea = new ExtensionsAreaImpl(new DefaultPicoContainer());
     extensionsArea.registerExtensionPoint("ep1", TestExtensionClassOne.class.getName(), ExtensionPoint.Kind.BEAN_CLASS);
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" id=\"_7\" order=\"LAST\"><text>7</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" id=\"fst\" order=\"FIRST\"><text>1</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" id=\"id\"><text>3</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" id=\"_7\" order=\"LAST\"><text>7</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" id=\"fst\" order=\"FIRST\"><text>1</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" id=\"id\"><text>3</text></extension>"));
     ExtensionPoint<TestExtensionClassOne> extensionPoint = extensionsArea.getExtensionPoint("ep1");
     TestExtensionClassOne[] extensions = extensionPoint.getExtensions();
     assertEquals(3, extensions.length);
@@ -204,10 +205,10 @@ public class ExtensionsImplTest {
     TestExtensionClassOne extension = new TestExtensionClassOne("xxx");
     extensionPoint.registerExtension(extension);
     extensionPoint.unregisterExtension(extension);
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" order=\"BEFORE id\"><text>2</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" order=\"AFTER id\"><text>4</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" order=\"last, after _7\"><text>8</text></extension>"));
-    extensionsArea.registerExtension("", JDOMUtil.load("<extension point=\"ep1\" order=\"after:id, before _7, after fst\"><text>5</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" order=\"BEFORE id\"><text>2</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" order=\"AFTER id\"><text>4</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" order=\"last, after _7\"><text>8</text></extension>"));
+    registerExtension(extensionsArea, "", JDOMUtil.load("<extension point=\"ep1\" order=\"after:id, before _7, after fst\"><text>5</text></extension>"));
     extensionPoint.registerExtension(new TestExtensionClassOne("6"));
     extensions = extensionPoint.getExtensions();
     assertEquals(8, extensions.length);
@@ -221,6 +222,10 @@ public class ExtensionsImplTest {
     assertEquals("8", extensions[7].getText());
   }
 
+  public static void registerExtension(ExtensionsAreaImpl area, @NotNull final String pluginName, @NotNull final Element extensionElement) {
+    area.registerExtension(new DefaultPluginDescriptor(PluginId.getId(pluginName)), extensionElement, null);
+  }
+
   public interface MyInterface1 extends Runnable {
   }