google app engine .jsp error loading [javax.servlet.UnavailableException]

Question

I have seen many solutions to this problem but none worked, the thing is i've deployed a simple hello world to google cloud and everything went fine with servlets and .html pages, but when it comes to .jsp pages the server can't load it and throw an exception (though .jsp pages works fine locally). the solutions i've tried:

• using JDK instead of JRE (i changed the JRE system library in the project build path).
• tried to set the compiler level to 1.7 but found that app engine forces you to use 1.8.
• tried to add .jsp files to web.xml file manually.
• tried to put the index page as .jsp and also didn't work, currently the only .jsp file is called mua.jsp
• finally i made my friend deploy a hello world project with basic jsp file (also named mua) on his macbook to the same project on the cloud and also didn't work.

what i mean by "didn't work" is that the page didn't load but instead shown error 500.

what makes the situation really weird is with last few deploys from my friend the error changed to 404 with no exception thrown ..

the exception:

javax.servlet.UnavailableException: Class loading error for holder mua@1a7b9==org.apache.jsp.mua_jsp,jsp=/mua.jsp,order=-1,inst=false, javax.servlet.UnavailableException: Class loading error for holder org.apache.jsp.mua_jsp@918a9ac4==org.apache.jsp.mua_jsp,jsp=null,order=-1,inst=false, javax.servlet.UnavailableException: Class loading error for holder org.apache.jsp.mua_jsp@918a9ac4==org.apache.jsp.mua_jsp,jsp=null,order=-1,inst=false, javax.servlet.UnavailableException: Class loading error for holder mua@1a7b9==org.apache.jsp.mua_jsp,jsp=/mua.jsp,order=-1,inst=false] at org.eclipse.jetty.servlet.ServletHandler.initialize (ServletHandler.java:863) at org.eclipse.jetty.servlet.ServletContextHandler.startContext (ServletContextHandler.java:349) at org.eclipse.jetty.webapp.WebAppContext.startWebapp (WebAppContext.java:1406) at com.google.apphosting.runtime.jetty9.AppEngineWebAppContext.startWebapp (AppEngineWebAppContext.java:159) at org.eclipse.jetty.webapp.WebAppContext.startContext (WebAppContext.java:1368) at org.eclipse.jetty.server.handler.ContextHandler.doStart (ContextHandler.java:778) at org.eclipse.jetty.servlet.ServletContextHandler.doStart (ServletContextHandler.java:262) at org.eclipse.jetty.webapp.WebAppContext.doStart (WebAppContext.java:522) at com.google.apphosting.runtime.jetty9.AppEngineWebAppContext.doStart (AppEngineWebAppContext.java:116) at org.eclipse.jetty.util.component.AbstractLifeCycle.start (AbstractLifeCycle.java:68) at com.google.apphosting.runtime.jetty9.AppVersionHandlerMap.createHandler (AppVersionHandlerMap.java:244) at com.google.apphosting.runtime.jetty9.AppVersionHandlerMap.getHandler (AppVersionHandlerMap.java:182) at com.google.apphosting.runtime.jetty9.JettyServletEngineAdapter.serviceRequest (JettyServletEngineAdapter.java:109) at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchServletRequest (JavaRuntime.java:693) at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.dispatchRequest (JavaRuntime.java:655) at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run (JavaRuntime.java:625) at com.google.apphosting.runtime.JavaRuntime$NullSandboxRequestRunnable.run (JavaRuntime.java:819) at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run (ThreadGroupPool.java:274) at java.lang.Thread.run (Thread.java:745)

Answer 1

i got the solution, the problem was in using java 10 in eclipse as the default project system library, currently i'm using java 8 and the deploy and everything else went fine :).