Java 应用程序引擎端点调用TargetException

当我试图生成云端点客户端库时，我从Eclipse中得到以下错误。你知道这是什么原因吗？否则，代码中没有可察觉的错误

java.lang.reflect.InvocationTargetException
    at com.google.gdt.eclipse.appengine.swarm.wizards.GenerateSwarmApiAction$1.run(GenerateSwarmApiAction.java:82)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
Caused by: com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmGenerationException: com.google.appengine.repackaged.com.google.api.client.http.HttpResponseException: 500 Internal Server Error
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmApiCreator.createClientLibFromApiConfig(SwarmApiCreator.java:144)
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmApiCreator.createSwarmApi(SwarmApiCreator.java:258)
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmServiceCreator.create(SwarmServiceCreator.java:444)
    at com.google.gdt.eclipse.appengine.swarm.wizards.GenerateSwarmApiAction$1.run(GenerateSwarmApiAction.java:80)
    ... 1 more
Caused by: com.google.appengine.repackaged.com.google.api.client.http.HttpResponseException: 500 Internal Server Error
    at com.google.appengine.repackaged.com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1054)
    at com.google.api.server.spi.tools.CloudClientLibGenerator.postRequest(CloudClientLibGenerator.java:53)
    at com.google.api.server.spi.tools.CloudClientLibGenerator.generateClientLib(CloudClientLibGenerator.java:44)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.google.gdt.eclipse.appengine.swarm.wizards.helpers.SwarmApiCreator.createClientLibFromApiConfig(SwarmApiCreator.java:142)
    ... 4 more