本文介绍了应用程序在本地运行良好，但不会在GAE上启动的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图在GAE上撰写留言板教程，但徒劳无益。它在本地主机上运行完美，但未能在GAE上启动。我想知道我为什么找不到明显而简单的解决方案。无论如何，我使用的版本是1.6.5，这些都是日志错误：
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)
对于关键：
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)
你也可以解释一下如何去调试这个日志？从上到下？从下到上？任何有关调试的参考建议？
Also can you explain how goes debugging of this log? Top to bottom? Bottom to top? Any suggestion for reference on the debugging?
推荐答案
底线：我将'window-> prefs-> compiler'编译器（JDK）complience级别更改为1.6，它工作正常！
祝大家好运！
Bottom line: I changed in 'window->prefs->compiler' compiler (JDK) complience level to 1.6 and it worked!Good luck to all!
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