问题
I'm trying to make a guestbook tutorial work on GAE but in vain. It runs perfectly on localhost but fails to start on GAE. I wonder how I couldn't find a solution for something this obvious and simple. Anyway I use version 1.6.5 and those are the log errors:
2012-05-22 16:28:36.724 /guestbook 500 183ms 0kb Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20100101 Firefox/13.0
109.226.55.233 - - [22/May/2012:16:28:36 -0700] "GET /guestbook HTTP/1.1" 500 0 "http://guestbooktestingtutorial.appspot.com/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20100101 Firefox/13.0" "guestbooktestingtutorial.appspot.com" ms=183 cpu_ms=397 api_cpu_ms=0 cpm_usd=0.011064 instance=00c61b117cdcbcf1fe4c8dc60eab0832828978
W 2012-05-22 16:28:36.721
Failed startup of context com.google.apphosting.utils.jetty.RuntimeAppEngineWebAppContext@161509b{/,/base/data/home/apps/s~guestbooktestingtutorial/1.359093852525748087}
org.mortbay.util.MultiException[java.lang.UnsupportedClassVersionError: guestbook/GuestbookServlet : Unsupported major.minor version 51.0, java.lang.UnsupportedClassVersionError: guestbook/SignGuestbookServlet : Unsupported major.minor version 51.0]
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:656)
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 com.google.apphosting.runtime.jetty.AppVersionHandlerMap.createHandler(AppVersionHandlerMap.java:202)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.getHandler(AppVersionHandlerMap.java:171)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:123)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:477)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:449)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:455)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:695)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:333)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:325)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:453)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
at java.lang.Thread.run(Thread.java:679)
java.lang.UnsupportedClassVersionError: guestbook/GuestbookServlet : Unsupported major.minor version 51.0
at com.google.appengine.runtime.Request.process-85e2c1c92188b0ad(Request.java)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
at org.mortbay.util.Loader.loadClass(Loader.java:91)
at org.mortbay.util.Loader.loadClass(Loader.java:71)
at org.mortbay.jetty.servlet.Holder.doStart(Holder.java:73)
at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:242)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:685)
at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1250)
at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:517)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:467)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:449)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:455)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:695)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:333)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:325)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:453)
at java.lang.Thread.run(Thread.java:679)
java.lang.UnsupportedClassVersionError: guestbook/SignGuestbookServlet : Unsupported major.minor version 51.0
at com.google.appengine.runtime.Request.process-85e2c1c92188b0ad(Request.java)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
at org.mortbay.util.Loader.loadClass(Loader.java:91)
at org.mortbay.util.Loader.loadClass(Loader.java:71)
at org.mortbay.jetty.servlet.Holder.doStart(Holder.java:73)
at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:242)
at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:685)
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 com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:449)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:455)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:695)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:333)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:325)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:453)
at java.lang.Thread.run(Thread.java:679)
And for the critical:
C 2012-05-22 16:28:36.722
Uncaught exception from servlet
javax.servlet.UnavailableException: Initialization failed.
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.createHandler(AppVersionHandlerMap.java:211)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.getHandler(AppVersionHandlerMap.java:171)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:123)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:477)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:449)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:455)
at com.google.tracing.TraceContext.runInContext(TraceContext.java:695)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:333)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:325)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:453)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
at java.lang.Thread.run(Thread.java:679)
Also can you explain how goes debugging of this log? Top to bottom? Bottom to top? Any suggestion for reference on the debugging?
回答1:
Ok finaly got it. As I saw in like 10 questions before it was a problem with JDK 1.7. Though I didn't realize how to change it right. I tried window->prefs->installed JREs to choose/add jdk1.7/jre1.7/jre1.6... but in vain. Even if you activate jre1.6 here (and in the end it didn't matter what to choose here) you need to choose active JDK in other place.
Bottom line: I changed in 'window->prefs->compiler' compiler (JDK) complience level to 1.6 and it worked! Good luck to all!
回答2:
I think the error you are looking for is this one:
java.lang.UnsupportedClassVersionError: guestbook/GuestbookServlet : Unsupported major.minor version 51.0
You are targeting your JDK in Eclipse, but that target isn't the same as what is on App Engine. I suggest untargeting the JDK and try deploying it again.
来源：https://stackoverflow.com/questions/10712034/app-works-fine-locally-but-it-wont-launch-on-gae