title: ClassCastException:com.google.appengine.tools.development.ApiProxyLocalImpl cannot be cast to com.google.appengine.tools.development.ApiProxyLocal
body: <p>I'm new in developing maven application and deploy to google app engine.
  i'm using <code>appengine 1.9.0</code> and <code>eclipse kepler 4.3</code></p>
  
  <p>However when I try to run, I got an error and according to this <a href="http://chstrongjavablog.blogspot.com/2012/05/some-errors-solutions-down-way.html" rel="noreferrer">blog</a> by chris, It suggested to remove this jar.</p>
  
  <pre><code>appengine-api-labs 
  appengine-api-stubs 
  appengine-testing
  </code></pre>
  
  <p>I already removed it in the libraries and tried maven clean but the error still appear.
  below is my libraries. </p>
  
  <p><img src="https://i.stack.imgur.com/u2N7e.png" alt="libraries"></p>
  
  <p>below is the full console error:</p>
  
  <pre><code>WARNING: failed _ah_ServeBlobFilter: java.lang.ClassCastException: com.google.appengine.tools.development.ApiProxyLocalImpl cannot be cast to com.google.appengine.tools.development.ApiProxyLocal
  3 20, 2014 2:34:57 午前 com.google.apphosting.utils.jetty.JettyLogger warn
  WARNING: Failed startup of context com.google.appengine.tools.development.DevAppEngineWebAppContext@87ec13{/,C:\Users\Annette\Desktop\WebCaller\src\main\webapp}
  java.lang.ClassCastException: com.google.appengine.tools.development.ApiProxyLocalImpl cannot be cast to com.google.appengine.tools.development.ApiProxyLocal
      at com.google.appengine.api.blobstore.dev.ServeBlobFilter.init(ServeBlobFilter.java:55)
      at org.mortbay.jetty.servlet.FilterHolder.doStart(FilterHolder.java:97)
      at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
      at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:662)
      at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
      at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
      at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
      at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
      at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
      at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
      at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
      at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
      at org.mortbay.jetty.Server.doStart(Server.java:224)
      at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
      at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:250)
      at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:305)
      at com.google.appengine.tools.development.AutomaticInstanceHolder.startUp(AutomaticInstanceHolder.java:26)
      at com.google.appengine.tools.development.AbstractModule.startup(AbstractModule.java:79)
      at com.google.appengine.tools.development.Modules.startup(Modules.java:97)
      at com.google.appengine.tools.development.DevAppServerImpl.doStart(DevAppServerImpl.java:255)
      at com.google.appengine.tools.development.DevAppServerImpl.access$000(DevAppServerImpl.java:47)
      at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:213)
      at com.google.appengine.tools.development.DevAppServerImpl$1.run(DevAppServerImpl.java:211)
      at java.security.AccessController.doPrivileged(Native Method)
      at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:211)
      at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:277)
      at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
      at com.google.appengine.tools.development.DevAppServerMain.run(DevAppServerMain.java:219)
      at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:210)
  </code></pre>
  
  <p>can anyone point it out? Thanks.</p>