title: java.lang.NoClassDefFoundError: com/google/appengine/api/datastore/AsyncDatastoreService
body: <p>I am triying yo develop a GAE servlet based backend module. I am using android studio with app engine sdk 1.9.28. How ever i am getting the following error:</p>
  
  <hr>
  
  <pre><code>java.lang.NoClassDefFoundError: com/google/appengine/api/datastore/AsyncDatastoreService 
  </code></pre>
  
  <p>error when my code reaches:</p>
  
  <pre><code>ObjectifyService.register(Classified.class);
  </code></pre>
  
  <p>Here is the stack trace:</p>
  
  <pre><code>java.lang.NoClassDefFoundError: com/google/appengine/api/datastore/AsyncDatastoreService
  at com.googlecode.objectify.ObjectifyService.&amp;lt;clinit&amp;gt;(ObjectifyService.java:20)
  at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:47)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:128)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
  at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
  at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
  at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
  at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
  at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
  at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
  at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
  at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
  at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
  at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:512)
  at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
  at org.mortbay.jetty.Server.handle(Server.java:326)
  at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
  at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
  at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
  at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
  at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
  at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
  at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
  Caused by: java.lang.ClassNotFoundException: com.google.appengine.api.datastore.AsyncDatastoreService
  at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
  at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:199)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
  </code></pre>