diff -r 70ff060e1674 -r d382dacfd73f rt/core/src/main/java/org/apidesign/bck2brwsr/core/impl/JavaScriptProcesor.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rt/core/src/main/java/org/apidesign/bck2brwsr/core/impl/JavaScriptProcesor.java	Tue Feb 26 16:54:16 2013 +0100
@@ -0,0 +1,100 @@
+/**
+ * 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.core.impl;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import javax.annotation.processing.AbstractProcessor;
+import javax.annotation.processing.Completion;
+import javax.annotation.processing.Completions;
+import javax.annotation.processing.Messager;
+import javax.annotation.processing.Processor;
+import javax.annotation.processing.RoundEnvironment;
+import javax.lang.model.element.AnnotationMirror;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.ElementKind;
+import javax.lang.model.element.ExecutableElement;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.element.VariableElement;
+import javax.lang.model.type.TypeKind;
+import javax.tools.Diagnostic;
+import org.apidesign.bck2brwsr.core.JavaScriptBody;
+import org.openide.util.lookup.ServiceProvider;
+
+/**
+ *
+ * @author Jaroslav Tulach <jtulach@netbeans.org>
+ */
+@ServiceProvider(service = Processor.class)
+public final class JavaScriptProcesor extends AbstractProcessor {
+    @Override
+    public Set<String> getSupportedAnnotationTypes() {
+        Set<String> set = new HashSet<>();
+        set.add(JavaScriptBody.class.getName());
+        return set;
+    }
+    
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+        final Messager msg = processingEnv.getMessager();
+        for (Element e : roundEnv.getElementsAnnotatedWith(JavaScriptBody.class)) {
+            if (e.getKind() != ElementKind.METHOD && e.getKind() != ElementKind.CONSTRUCTOR) {
+                continue;
+            }
+            ExecutableElement ee = (ExecutableElement)e;
+            List<? extends VariableElement> params = ee.getParameters();
+            
+            JavaScriptBody jsb = e.getAnnotation(JavaScriptBody.class);
+            if (jsb == null) {
+                continue;
+            }
+            String[] arr = jsb.args();
+            if (params.size() != arr.length) {
+                msg.printMessage(Diagnostic.Kind.ERROR, "Number of args arguments does not match real arguments!", e);
+            }
+            if (ee.getReturnType().getKind() == TypeKind.LONG) {
+                msg.printMessage(Diagnostic.Kind.WARNING, "Don't return long. Return double and convert it to long in Java code.", e);
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public Iterable<? extends Completion> getCompletions(Element e, 
+        AnnotationMirror annotation, ExecutableElement member, String userText
+    ) {
+        StringBuilder sb = new StringBuilder();
+        if (e.getKind() == ElementKind.METHOD && member.getSimpleName().contentEquals("args")) {
+            ExecutableElement ee = (ExecutableElement) e;
+            String sep = "";
+            sb.append("{ ");
+            for (VariableElement ve : ee.getParameters()) {
+                sb.append(sep).append('"').append(ve.getSimpleName())
+                    .append('"');
+                sep = ", ";
+            }
+            sb.append(" }");
+            return Collections.nCopies(1, Completions.of(sb.toString()));
+        }
+        return null;
+    }
+
+    
+}