diff -r 000000000000 -r 35daab73e225 rt/aot/src/main/java/org/apidesign/bck2brwsr/aot/RetroLambda.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rt/aot/src/main/java/org/apidesign/bck2brwsr/aot/RetroLambda.java	Sat Sep 13 13:44:01 2014 +0200
@@ -0,0 +1,121 @@
+/**
+ * Back 2 Browser Bytecode Translator
+ * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. Look for COPYING file in the top folder.
+ * If not, see http://opensource.org/licenses/GPL-2.0.
+ */
+package org.apidesign.bck2brwsr.aot;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import net.orfjackal.retrolambda.LambdaClassBackporter;
+import net.orfjackal.retrolambda.LambdaClassDumper;
+import net.orfjackal.retrolambda.LambdaClassSaver;
+import net.orfjackal.retrolambda.LambdaReifier;
+import net.orfjackal.retrolambda.LambdaUsageBackporter;
+import net.orfjackal.retrolambda.asm.Opcodes;
+import org.apidesign.bck2brwsr.core.ExtraJavaScript;
+import org.apidesign.vm4brwsr.Bck2Brwsr;
+
+/**
+ *
+ * @author Jaroslav Tulach
+ */
+@ExtraJavaScript(processByteCode = false, resource="")
+final class RetroLambda extends LambdaClassSaver implements BytecodeProcessor {
+    private Map<String,byte[]> converted;
+    
+    public RetroLambda() {
+        super(null, Opcodes.V1_7);
+    }
+
+    @Override
+    public void saveIfLambda(String className, byte[] bytecode) {
+        if (LambdaReifier.isLambdaClassToReify(className)) {
+            try {
+                System.out.println("Saving lambda class: " + className);
+                byte[] backportedBytecode = LambdaClassBackporter.transform(bytecode, Opcodes.V1_7);
+                putBytecode(className, backportedBytecode);
+            } catch (Throwable t) {
+                // print to stdout to keep in sync with other log output
+                throw new IllegalStateException("ERROR: Failed to backport lambda class: " + className);
+            }
+        }
+    }
+
+    private void putBytecode(String className, byte[] backportedBytecode) {
+        if (converted == null) {
+            converted = new HashMap<>();
+        }
+        converted.put(className, backportedBytecode);
+    }
+    
+    @Override
+    public Map<String, byte[]> process(
+        String className, byte[] byteCode, Bck2Brwsr.Resources resources
+    ) throws IOException {
+        int minor = byteCode[4] << 8 | byteCode[5];
+        int major = byteCode[6] << 8 | byteCode[7];
+        System.err.println("processing: " + className + " major: "+ major + " minor: " + minor);
+        if (major <= 51) {
+            return null;
+        }
+        
+        ClassLoader prev = Thread.currentThread().getContextClassLoader();
+        try (LambdaClassDumper dumper = new LambdaClassDumper(this)) {
+            Thread.currentThread().setContextClassLoader(new ResLdr(resources));
+            dumper.install();
+            
+            byte[] newB = LambdaUsageBackporter.transform(byteCode, Opcodes.V1_7);
+            if (!Arrays.equals(newB, byteCode)) {
+                putBytecode(className, newB);
+            }
+        } finally {
+            Thread.currentThread().setContextClassLoader(prev);
+        }
+        
+        Map<String, byte[]> ret = converted;
+        converted = null;
+        return ret;
+    }
+   
+    private static final class ResLdr extends ClassLoader {
+        private final Bck2Brwsr.Resources res;
+
+        public ResLdr(Bck2Brwsr.Resources res) {
+            this.res = res;
+        }
+        
+        @Override
+        public Class<?> loadClass(String name) throws ClassNotFoundException {
+            Class<?> c = findLoadedClass(name);
+            if (c != null) {
+                return c;
+            }
+            String r = name.replace('.', '/') + ".class";
+            try (InputStream is = res.get(r)) {
+                if (is == null) {
+                    throw new ClassNotFoundException(name);
+                }
+                byte[] arr = Bck2BrwsrJars.readFrom(is);
+                return defineClass(name, arr, 0, arr.length);
+            } catch (IOException e) {
+                return super.loadClass(name);
+            }
+        }
+    }    
+}