App Engine / Quercus datastore prepare query error - java

I'm trying to replicate the java guestbook example on Quercus on AppEngine and I'm getting an error having to do with preparing the query:
$greetings = $datastore->prepare($query)->asIterable();
I'm not a java developer so I can't make sense of the error trace. How can I get the greeting items without triggering this error?
Here is the entire error page:
HTTP ERROR 500
Problem accessing /index.php. Reason:
INTERNAL_SERVER_ERROR
Caused by:
java.lang.NullPointerException at
com.google.appengine.api.datastore.dev.LocalDatastoreService.next(LocalDatastoreService.java:1089)
at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source) at
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at
java.lang.reflect.Method.invoke(Unknown Source) at
com.google.appengine.tools.development.ApiProxyLocalImpl$AsyncApiCall.callInternal(ApiProxyLocalImpl.java:498)
at
com.google.appengine.tools.development.ApiProxyLocalImpl$AsyncApiCall.call(ApiProxyLocalImpl.java:452)
at
com.google.appengine.tools.development.ApiProxyLocalImpl$AsyncApiCall.call(ApiProxyLocalImpl.java:430)
at java.util.concurrent.Executors$PrivilegedCallable$1.run(Unknown
Source) at java.security.AccessController.doPrivileged(Native Method)
at java.util.concurrent.Executors$PrivilegedCallable.call(Unknown
Source) at java.util.concurrent.FutureTask$Sync.innerRun(Unknown
Source) at java.util.concurrent.FutureTask.run(Unknown Source) at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

If it's a null pointer exception then you are trying to access a method or property of a null object
First you need to check if $datastore is null, then if the return of the query is not null. Also you need to check if that error is on that particular line of code (maybe it fails somewhere else)
You can access the database at this link /_ah/admin. Maybe there is a corrupt entity in there

Related

vert.x getting - failed to create a child event loop

I am creating about 150 files of around 5MB sizes. Vertx file APIs gives an exception randomly after creating 10-15 files "failed to create a child event loop".
(I am using vertx3 and java8)
Below is my code snippet (After I get a callback then only I call the function again to create the next file. So, file creation is never concurrent):
Vertx.vertx().fileSystem().writeFile(filepath,
Buffer.buffer(dataList.toString()), result -> {
if (result.succeeded()) {
System.out.println("File written");
} else {
System.err.println("Oh oh ..." + result.cause());
}
lambda.callback();
});
Below is my exception stack trace:
java.lang.IllegalStateException: failed to create a child event loop
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:68)
at io.netty.channel.MultithreadEventLoopGroup.<init>(MultithreadEventLoopGroup.java:49)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:61)
at io.netty.channel.nio.NioEventLoopGroup.<init>(NioEventLoopGroup.java:52)
at io.vertx.core.impl.VertxImpl.<init>(VertxImpl.java:132)
at io.vertx.core.impl.VertxImpl.<init>(VertxImpl.java:126)
at io.vertx.core.impl.VertxImpl.<init>(VertxImpl.java:122)
at io.vertx.core.impl.VertxFactoryImpl.vertx(VertxFactoryImpl.java:34)
at io.vertx.core.Vertx.vertx(Vertx.java:78)
at rc_datawarehouse.CsvToJsonChunkWriter.writeCsvChunkToFiles(CsvToJsonChunkWriter.java:73)
at rc_datawarehouse.CsvToJsonReadWrite.lambda$2(CsvToJsonReadWrite.java:119)
at rc_datawarehouse.CsvToJsonReadWrite$$Lambda$16/1470881859.handle(Unknown Source)
at io.vertx.core.file.impl.AsyncFileImpl.handleData(AsyncFileImpl.java:335)
at io.vertx.core.file.impl.AsyncFileImpl.lambda$doRead$285(AsyncFileImpl.java:320)
at io.vertx.core.file.impl.AsyncFileImpl$$Lambda$17/1067800899.handle(Unknown Source)
at io.vertx.core.file.impl.AsyncFileImpl$2.lambda$done$289(AsyncFileImpl.java:408)
at io.vertx.core.file.impl.AsyncFileImpl$2$$Lambda$18/1632681662.handle(Unknown Source)
at io.vertx.core.impl.ContextImpl.lambda$wrapTask$15(ContextImpl.java:314)
at io.vertx.core.impl.ContextImpl$$Lambda$5/1780132728.run(Unknown Source)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:357)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)
at java.lang.Thread.run(Unknown Source)
Caused by: io.netty.channel.ChannelException: failed to open a new selector
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:128)
at io.netty.channel.nio.NioEventLoop.<init>(NioEventLoop.java:120)
at io.netty.channel.nio.NioEventLoopGroup.newChild(NioEventLoopGroup.java:87)
at io.netty.util.concurrent.MultithreadEventExecutorGroup.<init>(MultithreadEventExecutorGroup.java:64)
... 22 more
Caused by: java.io.IOException: Unable to establish loopback connection
at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
at sun.nio.ch.PipeImpl$Initializer.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.ch.PipeImpl.<init>(Unknown Source)
at sun.nio.ch.SelectorProviderImpl.openPipe(Unknown Source)
at java.nio.channels.Pipe.open(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.<init>(Unknown Source)
at sun.nio.ch.WindowsSelectorProvider.openSelector(Unknown Source)
at io.netty.channel.nio.NioEventLoop.openSelector(NioEventLoop.java:126)
... 25 more
Caused by: java.net.SocketException: No buffer space available (maximum connections reached?): connect
at sun.nio.ch.Net.connect0(Native Method)
at sun.nio.ch.Net.connect(Unknown Source)
at sun.nio.ch.Net.connect(Unknown Source)
at sun.nio.ch.SocketChannelImpl.connect(Unknown Source)
at java.nio.channels.SocketChannel.open(Unknown Source)
at sun.nio.ch.PipeImpl$Initializer$LoopbackConnector.run(Unknown Source)
... 34 more
I got my answer from the forum here (Thanks Jez)
Vertx.vertx() is the culprit. It creates a new vertx every time leading to multiple eventloops which seems to be the problem.
I cached it in a variable, rather than using Vertx.vertx() every time and it worked
cachedVertx.fileSystem().writeFile(...)

Calling my WebService via AJAX more often causes a server fault

I have a class that I run on the Java SE that gets called through a thread every second. Everything works fine.
However when I transform this into a WebService and call it via AJAX every second, I get a SOAP server fault. However if I call it every 6 seconds, everything is fine.
The method I used to call cannot perform the work. It actually succeeds to read and parse XML, but when converted to a WebService the XML parsing crashes.
What could cause the fault, when calling the WebService more often?
Here is the exception thrown on the server side :
[Fatal Error] :1:7: A pseudo attribute name is expected.
Sep 25, 2014 3:22:46 PM com.sun.xml.internal.ws.server.sei.TieHandler createResponse
SEVERE: null
java.lang.NullPointerException
at Targets.XML.TESXMLStringToArrays(XML.java:209)
at Navires.Vessel.allVessels(Vessel.java:137)
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.Trampoline.invoke(Unknown Source)
at sun.reflect.GeneratedMethodAccessor7.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.MethodUtil.invoke(Unknown Source)
at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.xml.internal.ws.api.server.MethodUtil.invoke(Unknown Source)
at com.sun.xml.internal.ws.api.server.InstanceResolver$1.invoke(Unknown Source)
at com.sun.xml.internal.ws.server.InvokerTube$2.invoke(Unknown Source)
at com.sun.xml.internal.ws.server.sei.SEIInvokerTube.processRequest(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber.__doRun(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber._doRun(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber.doRun(Unknown Source)
at com.sun.xml.internal.ws.api.pipe.Fiber.runSync(Unknown Source)
at com.sun.xml.internal.ws.server.WSEndpointImpl$2.process(Unknown Source)
at com.sun.xml.internal.ws.transport.http.HttpAdapter$HttpToolkit.handle(Unknown Source)
at com.sun.xml.internal.ws.transport.http.HttpAdapter.handle(Unknown Source)
at com.sun.xml.internal.ws.transport.http.server.WSHttpHandler.handleExchange(Unknown Source)
at com.sun.xml.internal.ws.transport.http.server.WSHttpHandler.handle(Unknown Source)
at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source)
at sun.net.httpserver.AuthFilter.doFilter(Unknown Source)
at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source)
at sun.net.httpserver.ServerImpl$Exchange$LinkHandler.handle(Unknown Source)
at com.sun.net.httpserver.Filter$Chain.doFilter(Unknown Source)
at sun.net.httpserver.ServerImpl$Exchange.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Here is the Exception thrown on the client side :
Sep 25, 2014 3:22:39 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [jsp] in context with path [/Map] threw exception [An exception occurred processing JSP page /targets.jsp at line 17
14:
15: Vessel M = V.getVesselPort() ;
16:
17: List<Vessel_Type> vessel =M.allVessels ();
18:
19: int j =0 ;
20: k="{"+'"'+"vessels"+'"'+":[" ;
Stacktrace:] with root cause
com.sun.xml.internal.ws.fault.ServerSOAPFaultException: Client received SOAP Fault from server: java.lang.NullPointerException Please see the server log to find more detail regarding exact cause of the failure.
at com.sun.xml.internal.ws.fault.SOAP11Fault.getProtocolException(Unknown Source)
at com.sun.xml.internal.ws.fault.SOAPFaultBuilder.createException(Unknown Source)
at com.sun.xml.internal.ws.client.sei.StubHandler.readResponse(Unknown Source)
at com.sun.xml.internal.ws.db.DatabindingImpl.deserializeResponse(Unknown Source)
at com.sun.xml.internal.ws.db.DatabindingImpl.deserializeResponse(Unknown Source)
at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(Unknown Source)
at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(Unknown Source)
at com.sun.xml.internal.ws.client.sei.SEIStub.invoke(Unknown Source)
at com.sun.proxy.$Proxy35.allVessels(Unknown Source)
at org.apache.jsp.targets_jsp._jspService(targets_jsp.java:90)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:335)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:534)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1081)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1566)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1523)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
It happens quite often when one client is calling the webservice . However when 2 clients are calling the web service it crashes immediately on the server and client sides . These exception are thrown when the Ajax call is performed .
EDIT: Added details.
The problem comes from the application architecture .
Here is how it works :
1) Server will open a socket connection to another server and get XML data close connection.
2) Server will format XML data as Array and make it available via webservice
3) Client calls the webservice to get the Array data.
So if i try to make Ajax call to the webservice less than 6 seconds i get errors i posted previously.
When i check the log in 1) i can see that the error is because the connection was closed so the 2) will automatically lead in error .
I can trigger the error by calling multiple times (Via eclipse many clicks to run java method calling the webservice ) or by using more than one client to call the webservice via JSP page having ajax, or simply by making ajax call very fast .
In 1) i can use many clients to open connection and get data very fastly witout any issue.
So the error i am getting can be solved if i declare the webmethod as synchronized , no errors will appear however it is very very slow as the multiple call will be hanging untill processed .
Where i am failing to understand is why in SE i can call 2 times a second and get data and even better i can do it within various machines at the same time without any log error and data are 100 clean meanwhile in webservice (EE) it fails ... Shall i reconfigure my webservice ? review the architecture ?
The problem comes from :
public class cnx {
static Socket socket ;
Now it is solved by removing socket from class attributes and putting it inside class as local variable.
But on the server side (where i pull data ) i can see many connections initiated meanwhile only one client is connected, this is due to multi calls (each Second and the data to be processed takes 2 seconds) .
if you have better alternative, please share .

Servlet threw load() exception

I know this error has been posted before but I can't understand the stack trace and would love somebodies help.
Basically when I enter the application the getValue("client") is null:
HttpSession validuser = request.getSession();
if (validuser.getValue("client") == null) {
response.sendRedirect("/profile/factfind/includes/session_timeout.jsp");
}
And I'm thinking it's something to do with the following error:
2013-01-09 13:14:35 NamingContextListener[/Tomcat-Standalone/localhost/profile]: Creating JNDI naming context
2013-01-09 13:14:35 StandardManager[/profile]: Seeding random number generator class java.security.SecureRandom
2013-01-09 13:14:35 StandardManager[/profile]: Seeding of random number generator has been completed
2013-01-09 13:14:35 StandardContext[/profile]: Posting standard context attributes
2013-01-09 13:14:35 StandardContext[/profile]: Configuring application event listeners
2013-01-09 13:14:35 StandardContext[/profile]: Sending application start events
2013-01-09 13:14:35 StandardContext[/profile]: Starting filters
2013-01-09 13:14:35 StandardContext[/profile]: Starting completed
2013-01-09 13:14:37 StandardContext[/profile]: Servlet /profile threw load() exception
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: -1 in the jsp file: null
Generated servlet error:
[javac] Compiling 1 source file
at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:85)
at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:248)
at org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:343)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:427)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:142)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:240)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:720)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:888)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:768)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3484)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:3710)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:777)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:760)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:538)
at org.apache.catalina.core.StandardHostDeployer.addChild(StandardHostDeployer.java:667)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.commons.beanutils.MethodUtils.invokeMethod(MethodUtils.java:216)
at org.apache.commons.digester.SetNextRule.end(SetNextRule.java:217)
at org.apache.commons.digester.Rule.end(Rule.java:253)
at org.apache.commons.digester.Digester.endElement(Digester.java:1222)
at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanEndElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.commons.digester.Digester.parse(Digester.java:1765)
at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:343)
at org.apache.catalina.core.StandardHost.install(StandardHost.java:762)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:443)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:377)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:808)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:335)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1156)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:697)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1148)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:311)
at org.apache.catalina.core.StandardService.start(StandardService.java:450)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2213)
at org.apache.catalina.startup.Catalina.start(Catalina.java:484)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:371)
at org.apache.catalina.startup.Catalina.process(Catalina.java:134)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:151)
The session exists in a different application that then loads "profile" so I'm not too sure what happens when one launches the other.
Any help would be much appreciated. Thanks.
Turns out the fix for me was the same as some forums had suggested. I create a new Tomcat installation in a directory with no spaces (i.e C:\Tomcat4.1) and that worked.
Don't know why or how but it did.
I think that's a problem
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: -1 in the jsp file: null
Cleanup your project (or manually remove all .class files) then try to compile from scratch. If error gone - check it should work. If not - you should apparently get this first error gone.
It seems getValue(String) method is deprecated. so try the following code null == validuser.getAttribute(String)

"Different objects with the same identifiers" error

I'm using in a Java project RMI + Hibernate and I'm experiencing problems related to NotUniqueException with the error "Different objects with the same identifier".
I've got several doubts:
I'm pretty surre that I don't copy nor create new objects with the same ide
ntifiers. Is it possible that RMI creates a new object from another one when I use it?
Which method is using Hibernate to know that two objects are the same? equals?
I know that Serializable is related to Hibernate but I don't know in what way?
How can I solve the "Differents objects error" using RMI at the same time?
Is it correct every time I use delete or save over an object use merge before?
The stack traces is:
org.orm.PersistentException: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [dcl.Administrador#10]
at org.orm.PersistentSession.saveOrUpdate(PersistentSession.java:648)
at org.orm.PersistentManager.saveObject(PersistentManager.java:274)
at dcl.AdministradorDAO.save(AdministradorDAO.java:240)
at dcl.BdAdministrador.guardarAdministrador(BdAdministrador.java:62)
at dcl.BdAdministrador.actualizarAdministrador(BdAdministrador.java:109)
at dcl.BdPrincipal.actualizarAdministrador(BdPrincipal.java:555)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
at sun.rmi.transport.Transport$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Thanks in advance.
If you're doing something like returning a hibernate object from an RMI method, then passing it back into another one, then you'll potentially need to reattach the object to the session. (see What is the proper way to re-attach detached objects in Hibernate?).
Perhaps give some more info on what you're attempting if this doesn't help.

UnknownHostException while redirecting queries to google and getting results in JSon object

Loading classifier from D:\PROJECT\classifiers\NERDemo\classifiers\ner-eng-ie.crf-3-all2008.ser.gz ... done [2.0 sec].
Original Query was riot in India.
Parsing Queries and expanding tokens from the Ontologies..
{locations=[India], events=[riot]}
Search query is null
Something went wrong...
java.net.UnknownHostException: ajax.googleapis.com
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.<init>(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at org.girs2.SearchHandler.makeQuery(SearchHandler.java:35)
at org.girs2.GIRS.search(GIRS.java:37)
at org.girs2.GIRS.main(GIRS.java:62)
Exception in thread "main" java.lang.NullPointerException
at org.girs2.GIRS.search(GIRS.java:44)
at org.girs2.GIRS.main(GIRS.java:62)
Looks like you probably have or had a DNS lookup failure. This tells you what happened:
java.net.UnknownHostException: ajax.googleapis.com
If you always get this exception and you can otherwise access this host by name, then I don't know what this could be, but odds are that this was a temporary DNS failure.
What should you do when you get this Exception? Well, if the address is one that you fully expect you should be able to get to -- such as this one -- then when you catch the Exception, you sleep for a while (perhaps 10 or 15 seconds, maybe even 30 or 60 seconds, depending on your application's needs) and try again.
If after several retries -- don't just retry forever! -- you still cannot reach the site, then log a reasonable complaint or otherwise complain that you cannot reach the site and have your application exit.
There's not much you can do when DNS fails except give up or wait and try again.

Categories