“VerifyError: Expecting a stackmap frame” using Play Framework and Google App Engine

Question

I have a Google App Engine webapp running with Play Framework 1.2.X . After Google changed their requirement to the webapp being built with Java 7 I have been struggling with a few different instances of VerifyError in the code. I've been able to work around a few, but there is one that I can't seem to get around. When running I get a stacktrace (see far below).

I think the problem occurs because of byte manipulation by Play Framework using Javassist . I see that others with related problems are able to get around it by using -XX:-UseSplitVerifier as argument to the VM, but that doesn't seem to be an option on Google App Engine .

I have tried with newer releases of Javassist and even using their master, but the problem is still the same.

I would file a bug report to Javassist if I knew how Play Framework was doing their magic and in more details how the problems occurs. It seems like the problem happens because of how some of the if tests in the class play.data.validation.Validation are structured, but that is really more of a guess then something I know.

Google App Engine have this form where one can ask to be allowed to continue to use Java 6 for a while, but I haven't got any response on my two inquires.

Now I'm really blank and don't know how to solve this. I'm in need of updating my webapp and would like to not have to rewrite the whole thing to do this (though I seem to have to do that in the longer run anyways).

Anyone got any hints? Here is the stacktrace The stacktrace is as follows:

play.exceptions.JavaExecutionException: Expecting a stackmap frame at branch target 36 in method controllers.SomeController.somemethod(Ljava/lang/String;)V at offset 14
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:237)
at play.server.ServletWrapper$ServletInvocation.execute(ServletWrapper.java:561)
at play.Invoker$Invocation.run(Invoker.java:278)
at play.server.ServletWrapper$ServletInvocation.run(ServletWrapper.java:552)
at play.Invoker.invokeInThread(Invoker.java:68)
at play.server.ServletWrapper.service(ServletWrapper.java:143)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.JdbcMySqlConnectionCleanupFilter.doFilter(JdbcMySqlConnectionCleanupFilter.java:60)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:254)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:146)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:446)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:438)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:445)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:220)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:309)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:301)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:442)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
at java.lang.Thread.run(Thread.java:724)
Caused by: java.lang.VerifyError: Expecting a stackmap frame at branch target 36 in method controllers.SomeController.somemethod(Ljava/lang/String;)V at offset 14
at controllers.SomeController.someOtherMethod(SomeController.java:83)
at play.mvc.ActionInvoker.invokeWithContinuation(ActionInvoker.java:557)
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:508)
at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:484)
at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:479)
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:161)
at play.server.ServletWrapper$ServletInvocation.execute(ServletWrapper.java:561)
at play.Invoker$Invocation.run(Invoker.java:278)
at play.server.ServletWrapper$ServletInvocation.run(ServletWrapper.java:552)
at play.Invoker.invokeInThread(Invoker.java:68)
at play.server.ServletWrapper.service(ServletWrapper.java:143)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:438)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:445)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:220)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:309)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:301)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:442)
... 1 more

Answer 1

Since Java 7, the byte code format requires so called stack map frames at each target of a jump instruction. Before, the JVM's verifier applied type inference to assure the validity of the byte code. However, with Java 7, the verifier needs this information to be put in the class file, otherwise, you encounter this VerifierError .

The unfortunate answer is that the information is not there unless you put it there. It is so to say not a bug of Javassist which is able to add these stack map frames, it is a problem of the Play framework not instructing Javassist to do so. Play is using Javassist's low level API which does not add these frames manually. It is absolutely possible to do this with Javassist as discussed for example for PowerMock .

You might need to upgrade to version 2 of the Play framework.