Google App Engine (GAE) on Eclipse

Discovered Vaadin recently. Trying to follow the instructions in the book. My environment is 64 bit Ubuntu 10.04, Sun JDK 1.6.0_21, Eclipse 3.6 (Helios), Google plugin for Eclipse (App Engine SDK 1.3.5), Tomcat 7.0 beta, and Vaadin 6.4.1. Created a new project for GAE and got the following warning:

Classpath entry com.google.appengine.eclipse.core.GAE_CONTAINER will not be exported or published. Runtime ClassNotFoundExceptions may result.

Following warning reported for appengine-web.xml:

No grammar constraints (DTD or XML schema) detected for the document.

When debugging the project, got the following error:

Aug 1, 2010 11:10:09 AM com.vaadin.terminal.gwt.server.GAEApplicationServlet service
SEVERE: java.lang.NullPointerException: java.lang.NullPointerException
at com.google.appengine.api.NamespaceManager.get(NamespaceManager.java:122)
at com.google.appengine.api.memcache.MemcacheServiceImpl.getEffectiveNamespace(MemcacheServiceImpl.java:237)
at com.google.appengine.api.memcache.MemcacheServiceImpl.put(MemcacheServiceImpl.java:358)
at com.vaadin.terminal.gwt.server.GAEApplicationServlet.service(GAEApplicationServlet.java:217)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:201)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:163)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:108)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:556)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:402)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:249)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:267)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:245)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:260)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

Thanks for any advice.

Hi,

Same problem here :
http://vaadin.com/forum/-/message_boards/message/228224

Cheers,
HaDao