The reason for the error is because GAE library is not referenced to your project.
So As a result, the greeting application will definetly fail because u need to use GAE lib ie enhance tool to Enhance your class and this is failing. Try updating your plugin.make sure your plugin is operation before you run any app On Mon, Dec 13, 2010 at 6:47 PM, ken <yuanyun.ke...@gmail.com> wrote: > Hi, all: > I'm a newbie to google app engine. > After install GAE eclipse plugin, and create a Google Web > application project, it immediately reports error: "Could not find the > main class: com.google.appengine.tools.enhancer.Enhance. Program > exit". > > In the console: > Exception in thread "Main Thread" java.lang.NoClassDefFoundError: > com/google/appengine/tools/enhancer/Enhance > Caused by: java.lang.ClassNotFoundException: > com.google.appengine.tools.enhancer.Enhance > at java.net.URLClassLoader$1.run(URLClassLoader.java:202) > at java.net.URLClassLoader.findClass(URLClassLoader.java:190) > at java.lang.ClassLoader.loadClass(ClassLoader.java:307) > at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) > at java.lang.ClassLoader.loadClass(ClassLoader.java:248) > > I tested this with Eclipse 3.6/3.5, GAE 1.4/1.3, both report above > error. > > Run the guestbook provided in the SDK, it would report the > following error: > javax.jdo.JDOUserException: Persistent class "Class > guestbook.Greeting does not seem to have been enhanced. You may want > to rerun the enhancer and check for errors in the output." has no > table in the database, but the operation requires it. Please check the > specification of the MetaData for this class. > ... > Caused by: > Persistent class "Class guestbook.Greeting does not seem to have been > enhanced. You may want to rerun the enhancer and check for errors in > the output." has no table in the database, but the operation requires > it. Please check the specification of the MetaData for this class. > org.datanucleus.store.exceptions.NoTableManagedException: Persistent > class "Class guestbook.Greeting does not seem to have been enhanced. > You may want to rerun the enhancer and check for errors in the > output." has no table in the database, but the operation requires it. > Please check the specification of the MetaData for this class. > > Could anybody help on this, I would really very appreciate... > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to google-appeng...@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com<google-appengine%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appeng...@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
