Null Pointer Exception from Google AppEngine BackendSevice

Question

Null Pointer Exception from Google AppEngine BackendSevice

We have a Google App Engine Java project. It works fine. But the logs have a NULL Pointer Exception in the BackendService as follows

10.1.0.41 - - [13/Oct/2014:05:33:08 -0700] "POST /_ah/spi/BackendService.getApiConfigs HTTP/1.1" 500 89 - - ms=125 cpu_ms=15 cpm_usd=0.000010 app_engine_release=1.9.13 instance=00c61b117c84d9ef5a08d243b652ffc3c7589b
E 2014-10-13 18:03:08.271

com.google.api.server.spi.SystemService invokeServiceMethod: invokeServiceMethod: cause={0}
java.lang.NullPointerException
    at com.google.api.server.spi.BackendService.getApiConfigs(BackendService.java:45)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:45)
    at com.google.api.server.spi.SystemService.invokeServiceMethod(SystemService.java:189)
    at com.google.api.server.spi.SystemServiceServlet.execute(SystemServiceServlet.java:137)
    at com.google.api.server.spi.SystemServiceServlet.doPost(SystemServiceServlet.java:106)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    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)
    at java.lang.Thread.run(Thread.java:724)


com.google.api.server.spi.SystemService invokeServiceMethod: null
java.lang.NullPointerException
    at com.google.api.server.spi.BackendService.getApiConfigs(BackendService.java:45)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:45)
    at com.google.api.server.spi.SystemService.invokeServiceMethod(SystemService.java:189)
    at com.google.api.server.spi.SystemServiceServlet.execute(SystemServiceServlet.java:137)
    at com.google.api.server.spi.SystemServiceServlet.doPost(SystemServiceServlet.java:106)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    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)
    at java.lang.Thread.run(Thread.java:724)

I have the following configuration in web.xml

<servlet>
  <servlet-name>SystemServiceServlet</servlet-name>
  <servlet-class>com.google.api.server.spi.SystemServiceServlet</servlet-class>
  <init-param>
   <param-name>services</param-name>
   <param-value/>
  </init-param>
</servlet>
<servlet-mapping>
  <servlet-name>SystemServiceServlet</servlet-name>
  <url-pattern>/_ah/spi/*</url-pattern>
</servlet-mapping>

Why is this happening and how to fix this problem?

+3

java google-app-engine

Fizer khan 13 oct. '14 at 12:50

source to share

2 answers

user2492339 · Answer 1 · 2014-11-24T17:36:02+0000

I faced the same problem. Use jdk 1.7 instead of jdk 1.8 to build the project and download it again. This fixed it for me.

gturedi · Answer 2 · 2015-06-30T14:56:02+0000

it causes jdk version incompatibility. you should add source code level definition for backend gradle script project like below:

sourceCompatibility = JavaVersion.VERSION_1_7
targetCompatibility = JavaVersion.VERSION_1_7

Null Pointer Exception from Google AppEngine BackendSevice

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