NoClassDefFoundError on Google App Engine

[katafractari]

Version: 7.4.0 and up

Code Snippet

Call callResponse = Call.creator(new com.twilio.type.PhoneNumber(call.getTo()), new com.twilio.type.PhoneNumber(call.getFrom()), new URI(call.getAnswerUrl()))
.setStatusCallback(call.getHangupUrl())
.setStatusCallbackEvent(Collections.singletonList("completed"))
.create();

Exception / Log

java.lang.NoClassDefFoundError: java.net.ProxySelector is a restricted class. Please see the Google App Engine developer's guide for more details.
	at com.google.apphosting.runtime.security.shared.stub.java.net.ProxySelector.<clinit>(ProxySelector.java)
	at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:1145)
	at com.twilio.http.NetworkHttpClient.<init>(NetworkHttpClient.java:51)
	at com.twilio.http.TwilioRestClient$Builder.<init>(TwilioRestClient.java:66)
	at com.twilio.Twilio.getRestClient(Twilio.java:118)
	at com.twilio.base.Creator.create(Creator.java:45)
	at com.receivr.services.calls.twilio.TwilioClient.call(TwilioClient.java:84)
	at com.receivr.managers.CallFlowManager.callReceptionist(CallFlowManager.java:66)
	at com.receivr.managers.CallFlowEventManager.handleCallAnswer(CallFlowEventManager.java:314)
	at com.receivr.managers.CallFlowEventManager.waitForCallAnswer(CallFlowEventManager.java:273)
	at com.receivr.services.calls.twilio.servlets.WaitForReceptionistAnswerServlet.handleRequest(WaitForReceptionistAnswerServlet.java:49)
	at com.receivr.services.calls.twilio.servlets.TwilioServlet.doPost(TwilioServlet.java:72)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at com.google.inject.servlet.ServletDefinition.doServiceImpl(ServletDefinition.java:286)
	at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:276)
	at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:181)
	at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91)
	at com.google.inject.servlet.ManagedFilterPipeline.dispatch(ManagedFilterPipeline.java:120)
	at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:135)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
	at com.googlecode.objectify.ObjectifyFilter.doFilter(ObjectifyFilter.java:48)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
	at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:125)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
	at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:37)
	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:48)
	at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
	at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
	at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
	at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
	at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:257)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
	at org.mortbay.jetty.Server.handle(Server.java:326)
	at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
	at org.mortbay.jetty.HttpConnection$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$RequestRunnable.dispatchServletRequest(JavaRuntime.java:657)
	at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchRequest(JavaRuntime.java:619)
	at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:589)
	at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:453)
	at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:460)
	at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:293)
	at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:319)
	at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:311)
	at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:457)
	at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:263)
	at java.lang.Thread.run(Thread.java:745)

Steps to Reproduce

1. Include twilio-java SDK 7.4.0+
2. Make any REST call
3. If the application is deployed to Google App Engine (Java 7), the above exception is thrown. The exception is not thrown if we downgrade Twilio Java SDK to at least 7.3.0.

As far as I see, GAE platform uses a modified Apache HttpClient, which probably conflicts with the HttpClient that Twilio Java SDK uses.

[jimm-porch]

Until recently, Google imposed a "white list" on App Engine applications, where certain Java classes were prohibited from use. They just lifted that restriction for Java 8 applications and beyond.

On the JRE whitelist page they have a comment at the top saying "Important: This whitelist does not apply to the Java 8 runtime, which supports all public JDK APIs."

[codejudas]

We've created a PR to address this: #378

[codejudas]

@katafractari @jimm-porch We are releasing today so this should be fixed in 7.13.0 and 7.13.0-alpha-1. Thanks for your patience and help debugging :)