RMI - loading a class across a network

Hi,
I've written a client-server program which uses RMI. I can run the server where I put a class into the RMI registry on port 4301 and connect to it from my client with the url : "//hostname:4301/rmi_name".
This all works fine if I run it all on the same physical machine, as soon as I try to connect my client from a different machine I get "Unable to connect to //hostname:4301/rmi_name".
However, I can ping the hostname, so the network is active. I've tried changing the hostname to the ip address with no difference. I'm sure the rmi name matches because I can connect on the same physical machine. I've also tried prefixing the url with "http:" and "file:" - then I just get invalid url.
Anybody know what's wrong here?
Cheers
Tomas

I tried the same thing but still got the error.
I've discovered what I'm acutally getting is a java.rmi.UnmarshalException where the nested exception is java.lang.ClassNotFoundException.
I can connect to the remote registry and get a correct list of the bindings. But I get the above error when I try to actually look the object up, either with Naming.lookup or with LocateRegistry.getRegistry(host, port).lookup(name);
I think it's a codebase issue now. The two properties I'm setting are:
java.rmi.server.hostname to "<hostname>" java.rmi.server.codebase to "file:/<full pathname>"
I know this works locally, 'cos if I change the code base the local client won't find the _stub class (or other classes). I've also tried:
java.rmi.server.codebase "file://<hostname>/<path>" but that just gives a class loader permission error. I can get over that by setting the policy file, but then I just come back to the original error again.
Cheers
Tomas
btw generally to all: This isn't an applet. It's just an application running on the command line. Oh, and I was being a bit dumb, the "Unable to connect..." part is actually in my code. Sorry! ;-) Well spotted previous replier!

Similar Messages

RMI and the class loader delegation model

Hello,
I need to know what the class loader delagation chain looks like when RMI does dynamic class loading. What is the RMIClassLoader's parent? Does it delegate to Thread.currentThread().getContextClassLoader()?
In a test application I can debug the chain which looks like this:
sun.misc.Launcher$AppClassLoader@bac748
sun.misc.Launcher$ExtClassLoader@7172ea
The AppClassLoader is the class loader for the test and is coincident with getSystemClassLoader(). Its parent is the ExtClassLoader which I believe is in charge of loading anything from jre/lib/ext. But I don't know how to get a reference to the RMIClassLoader in order to find out what it's parent is.
I would appreciate any info on this.
Thanks in advance,
Joe

Well that was easy.
I just used the RMIClassLoader.getClassLoader(String codebase) and was able to determine the chain.
FYI: the chian is as follows:
ExtClassLoader <-- AppClassLoader <-- sun.rmi.server.LoaderHandler
Of interest, if you have a custom class loader its parent will most likely be the AppClassLoader but the rmi class loader will not chain off of your custom class loader. It does some interesting things in order for this to work. It will look for custom class loader to load interfaces but will use the RMIClassLoader to load stubs. Pretty cool.
Thanks anyway.
Joe

How to start rmi on a computer with 2 network cards ?

I would like to write a programm to get system informations from any linux computer connected to a network. A RMI server installed on each network computer measures the informations and send them to a RMI Client based on a central computer, where the information is stored on database.
Each computer is identified by its IP address. This is why the IP adress is sent with the string of system informations. For instance, the information sent for a CPU measure is :
<Computer>
<AddIP>192.168.1.1</AddIP>
<CPU><Frequency>500</Frequency><Brand>Intel</Brand></CPU>
</Computer>
In the case when a computer has two IP adresses : 192.168.1.1 and 192.168.2.64, if the computer is reached by 192.168.1.1 it should return the following string :
<Computer>
<AddIP>192.168.1.1</AddIP>
<CPU><Frequency>500</Frequency><Brand>Intel</Brand></CPU>
</Computer>
and if reached by 192.168.2.64 :
<Computer>
<AddIP>192.168.2.64</AddIP>
<CPU><Frequency>500</Frequency><Brand>Intel</Brand></CPU>
</Computer>
The string does not contains all IP adresses but these from which the computer was asked for a measurement. Here is the code for the RMI server :
public class ServeurAgent {
public ServeurAgent() {
try {
// we launched a RMI service for each IP address :
LocateRegistry.createRegistry(portRMIAgent);
// the 192.168.1.1 parameter for AgentImpl is only
     // used to generate the XML String
Agent agent1 = new AgentImpl(192.168.1.1);
Naming.rebind("rmi://192.168.1.1:1099/serviceRMI",agent);
Agent agent2 = new AgentImpl(192.168.2.64);
Naming.rebind("rmi://192.168.2.64:1099/serviceRMI",agent);
catch (Exception e) {
System.out.println("echec du lancement des Agents : "+e);
public static void main(String args[]) {
new ServeurAgent();
We hoped that when the RMI client asked for a measurement on one IP address we could get in the XML String the same IP address, but the problem is that whatever the IP adress is asked, the XML String always contains the same IP address. For example if we ask for a measurement on the 192.168.2.64 adress we have got :
<Computer>
<AddIP>192.168.1.1</AddIP>
<CPU><Frequency>500</Frequency><Brand>Intel</Brand></CPU>
</Computer>
instead of :
<Computer>
<AddIP>192.168.2.64</AddIP>
<CPU><Frequency>500</Frequency><Brand>Intel</Brand></CPU>
</Computer>
Do you have any idea of what could be the problem ? Is the code correctly written ?
Here is the code for the RMI client :
public void mesurer(ipAdress) {
try {
valeur_mesures = "";
          Agent agent = (Agent) Naming.lookup("rmi://"+ ipAdress +":1099/serviceRMI");
          // valeur_mesures is the XML string
          valeur_mesures = agent.getCPUs();
catch (MalformedURLException murle) {
System.out.println();
System.out.println("MalformedURLException");
System.out.println(murle);
catch (RemoteException re) {
System.out.println();
System.out.println("RemoteException");
System.out.println(re);
} catch (NotBoundException nbe) {
System.out.println();
System.out.println("NotBoundException");
System.out.println(nbe);
Thank you for your help.

You may have solved it by now but your code is using the wrong variables when binding objects:
Agent agent1 = new AgentImpl(192.168.1.1);
Naming.rebind("rmi://192.168.1.1:1099/serviceRMI",agent);
Agent agent2 = new AgentImpl(192.168.2.64);
Naming.rebind("rmi://192.168.2.64:1099/serviceRMI",agent);
Notice you are creating agents "agent1" and "agent2" but you are storing the stub of an instance called "agent".
Otherwise, it should work so long as the names you are binding the variables to are unique and not rebound anywhere else.

Lightroom across the network, is there ANY way?

We have to process large catalogs with 8000 plus images and are under a time limit of about a week tp process them ...usually.
We put the catalog on one PC we call the Master and would like to be able to have other staff work on the catalog from one of the other PC's on the network. We have 12 PC's on a peer to peer network ( no server) and I need to split up the load and have several people working on it at once. I need to be able to open a catalog from another PC, while several other people are doing the same thing on different parts of the catalog so I can get these jobs out the door without one person or PC managing the whole job.
We don't put it on an external hard drive and move from one PC to another, that still defeats the purpose.
So far LR says it cannot work across a network, so I can't open a catalog from a laptop and work on the project from home ( for example) and I don;'t want to be duplicating all 8000 images on all the PC's so we are at a point where I need to ask for help...
Right now I export part of the master catalog to anoter PC with the oiginal images copied to the second PC, make my edits and Export back to the Master PC in a subfolder by the dancers name. Slow, but it does work. I would rather not have to do that on multiple machines to speed up the project.
Isn't there some way I can open the master catalog form another PC on the network, make the corrections and do the export right there?
Thanks everyone - any help is appreciated!

No.
There are risky workarounds that allow you to open a catalog that's on the network, but none that allow multiple users to access the same catalog. Any such workaround is a sure-fire way to corrupt the whole thing.

Java.rmi.UnmarshalException: skeleton class not found but required for clie

Hello everyone,
I am new to RMI and getting a strange exception. I am using Java 1.5.0_07 both on client and server. They are running on the same machine, the rmi registry is started inside the server application.
I am wondering why java complains about skeletons, I thought they are automatically created when using java 5.0?
Please have a look at the stacktrace below.
Thank you for your help.
Best Regards
Patric
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
     java.rmi.UnmarshalException: error unmarshalling call header; nested exception is:
     java.rmi.UnmarshalException: skeleton class not found but required for client version
     sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:325)
     sun.rmi.transport.Transport$1.run(Transport.java:153)
     java.security.AccessController.doPrivileged(Native Method)
     sun.rmi.transport.Transport.serviceCall(Transport.java:149)
     sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:466)
     sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:707)
     java.lang.Thread.run(Thread.java:595)
     sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:247)
     sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:223)
     sun.rmi.server.UnicastRef.invoke(UnicastRef.java:343)
     sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
     java.rmi.Naming.lookup(Naming.java:84)
     org.apache.jsp.index_jsp._jspService(index_jsp.java:58)
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

The full class path information that I can gather is as follows (some of the library path locations could be suspect...):
Class path: /edge/node3/hotfix::/edge/node3/current/lib/JMdsApi.jar:/edge/node3/current/lib/MemoryProfilingAgent.jar:/edge/node3/current/lib/T2common-2.6.0-SNAPSHOT.3200.jar:/edge/node3/current/lib/T2scripting-jython.jar:/edge/node3/current/lib/activation.jar:/edge/node3/current/lib/alib.jar:/edge/node3/current/lib/alibom.jar:/edge/node3/current/lib/ant.jar:/edge/node3/current/lib/authapi.jar:/edge/node3/current/lib/bbdlapi.jar:/edge/node3/current/lib/bcpg-jdk15-136.jar:/edge/node3/current/lib/bcprov-jdk15-136.jar:/edge/node3/current/lib/c3p0-0.9.1.2.jar:/edge/node3/current/lib/castor-1.1-codegen-anttask.jar:/edge/node3/current/lib/castor-1.1-codegen.jar:/edge/node3/current/lib/castor-1.1-xml.jar:/edge/node3/current/lib/castor-1.1.jar:/edge/node3/current/lib/colt-1.2.0.jar:/edge/node3/current/lib/common-annotations.jar:/edge/node3/current/lib/commons-beanutils.jar:/edge/node3/current/lib/commons-codec-1.3.jar:/edge/node3/current/lib/commons-collections-3.2.1.jar:/edge/node3/current/lib/commons-jexl-1.1.jar:/edge/node3/current/lib/commons-lang-2.3.jar:/edge/node3/current/lib/commons-logging-1.1.1.jar:/edge/node3/current/lib/commons-net-1.4.1.jar:/edge/node3/current/lib/dsn.jar:/edge/node3/current/lib/eagleapi.jar:/edge/node3/current/lib/ezmorph-1.0.3.jar:/edge/node3/current/lib/f2-loader-1.8.jar:/edge/node3/current/lib/fasttrade-boviewer-1.0.1.jar:/edge/node3/current/lib/hsqldb.jar:/edge/node3/current/lib/icu4j-3.4.4.jar:/edge/node3/current/lib/ivy.jar:/edge/node3/current/lib/janino.jar:/edge/node3/current/lib/janus-sdk-1.7.0.0.jar:/edge/node3/current/lib/jasypt-1.4.1.jar:/edge/node3/current/lib/javolution.jar:/edge/node3/current/lib/jcalendar-1.3.2.jar:/edge/node3/current/lib/jcl-over-slf4j-1.5.6.jar:/edge/node3/current/lib/jcommon-1.0.9.jar:/edge/node3/current/lib/jconn2.jar:/edge/node3/current/lib/jconn3-6.05-b26214.jar:/edge/node3/current/lib/jdom.jar:/edge/node3/current/lib/jfreechart-1.0.5.jar:/edge/node3/current/lib/jgroups-all.jar:/edge/node3/current/lib/jline.jar:/edge/node3/current/lib/jmkv123p1.jar:/edge/node3/current/lib/jna.jar:/edge/node3/current/lib/joda-time-1.5.2.jar:/edge/node3/current/lib/jscience.jar:/edge/node3/current/lib/json-lib-2.2.1-jdk15.jar:/edge/node3/current/lib/jul-to-slf4j-1.5.6.jar:/edge/node3/current/lib/junit.jar:/edge/node3/current/lib/jython.jar:/edge/node3/current/lib/log4j-1.2.15.jar:/edge/node3/current/lib/log4j-over-slf4j-1.5.6.jar:/edge/node3/current/lib/loggablePreparedStatement-1.6.jar:/edge/node3/current/lib/looks-2.1.4.jar:/edge/node3/current/lib/mailapi.jar:/edge/node3/current/lib/model-12021.jar:/edge/node3/current/lib/mysql-connector-java-5.1.7-bin.jar:/edge/node3/current/lib/opencsv-1.8.jar:/edge/node3/current/lib/rfa.jar:/edge/node3/current/lib/rspcore.jar:/edge/node3/current/lib/slf4j-api-1.5.6.jar:/edge/node3/current/lib/slf4j-log4j12-1.5.6.jar:/edge/node3/current/lib/smtp.jar:/edge/node3/current/lib/smtphandler-0.6.jar:/edge/node3/current/lib/spring-2.5.2.jar:/edge/node3/current/lib/statsvn.jar:/edge/node3/current/lib/swingx-0.9.3.jar:/edge/node3/current/lib/t2-12021.jar:/edge/node3/current/lib/testng-5.9-jdk15.jar:/edge/node3/current/lib/tibmsg.jar:/edge/node3/current/lib/tibrvj.jar:/edge/node3/current/lib/trove.jar:/edge/node3/current/lib/velocity-tools.jar:/edge/node3/current/lib/velocity.jar:/edge/node3/current/lib/xalan.jar:/edge/node3/current/lib/xerces.jar:/edge/node3/current/lib/patng/activeio-core-3.0.0-incubator.jar:/edge/node3/current/lib/patng/activemq-core-4.1.1.jar:/edge/node3/current/lib/patng/avalon-framework-4.1.3.jar:/edge/node3/current/lib/patng/backport-util-concurrent-2.2.jar:/edge/node3/current/lib/patng/binding-1.4.0.jar:/edge/node3/current/lib/patng/cglib-nodep-2.1_3.jar:/edge/node3/current/lib/patng/common-1.30.jar:/edge/node3/current/lib/patng/commons-cli-1.0.jar:/edge/node3/current/lib/patng/commons-configuration-1.2.jar:/edge/node3/current/lib/patng/commons-discovery-0.2.jar:/edge/node3/current/lib/patng/commons-math-1.1.jar:/edge/node3/current/lib/patng/concurrent-1.3.4.jar:/edge/node3/current/lib/patng/geronimo-j2ee-management_1.0_spec-1.0.jar:/edge/node3/current/lib/patng/geronimo-jms_1.1_spec-1.0.jar:/edge/node3/current/lib/patng/logkit-1.0.1.jar:/edge/node3/current/lib/patng/mina-core-1.0.1.jar:/edge/node3/current/lib/patng/mina-filter-ssl-1.0.1.jar:/edge/node3/current/lib/patng/mina-java5-1.0.1.jar:/edge/node3/current/lib/patng/mx4j-remote-3.0.1.jar:/edge/node3/current/lib/patng/mx4j-tools-3.0.1.jar:/edge/node3/current/lib/patng/org.apache.felix.framework-1.0.0.jar:/edge/node3/current/lib/patng/org.osgi.core-1.0.0.jar:/edge/node3/current/lib/patng/pat-dt-common-1.18.jar:/edge/node3/current/lib/patng/pat-sdt-1.18.jar:/edge/node3/current/lib/patng/patNg-api-1.27.1.jar:/edge/node3/current/lib/patng/patNg-server-aoc-1.21.jar:/edge/node3/current/lib/patng/patNg-server-common-1.21.jar:/edge/node3/current/lib/patng/patNg-server-session-manager-1.21.jar:/edge/node3/current/lib/patng/patNg-utils-1.27.1.jar:/edge/node3/current/lib/patng/qpid-broker-2.2.2.0.jar:/edge/node3/current/lib/patng/qpid-client-2.2.2.0.jar:/edge/node3/current/lib/patng/qpid-common-2.2.2.0.jar:/edge/node3/current/lib/patng/qpid-mina-core-2.2.2.0.jar:/edge/node3/current/lib/patng/rsee-2.11.jar:/edge/node3/current/lib/patng/servlet-api-2.3.jar:/edge/node3/current/lib/patng/silk-1.3.jar:/edge/node3/current/lib/patng/slf4j-api-1.4.0.jar:/edge/node3/current/lib/patng/slf4j-log4j12-1.4.0.jar:/edge/node3/current/lib/patng/validation-1.2.0.jar
Boot class path: /apps/jdk/1.6.0_13/linux/jre/lib/resources.jar:/apps/jdk/1.6.0_13/linux/jre/lib/rt.jar:/apps/jdk/1.6.0_13/linux/jre/lib/sunrsasign.jar:/apps/jdk/1.6.0_13/linux/jre/lib/jsse.jar:/apps/jdk/1.6.0_13/linux/jre/lib/jce.jar:/apps/jdk/1.6.0_13/linux/jre/lib/charsets.jar:/apps/jdk/1.6.0_13/linux/jre/classes:/tmp/yjp200811122006.jar
Library path: /apps/jdk/1.6.0_13/linux/jre/lib/i386/server:/apps/jdk/1.6.0_13/linux/jre/lib/i386:/apps/jdk/1.6.0_13/linux/jre/../lib/i386::/edge/node3/current/lib:/home/eqdev/eqedgeuat/yourkit_7_5_11/yjp-7.5.11/bin/linux-x86-32:/edge/node3/current/lib:/home/eqdev/eqedgeuat/yourkit_7_5_11/yjp-7.5.11/bin/linux-x86-32:/usr/java/packages/lib/i386:/lib:/usr/lib

Problems using JAXB in windows(Failed to load Main-Class manifest)

Friends,
I am trying to use JAXB in windows environment. I have already included rt and xjc jar files in my system classpath.
I have sucessfully created java files using the xjc compiler(without the xjs map file). They rock!!
But I am facing problems while creating .xjs file from my dtd. I tried looking into previously discussed topics, with no help. :(
my command line:
java -jar C:\jaxb-1.0-ea\lib\jaxb-rt-1.0-ea.jar mySchemaFile.dtd
This is what i get :
Failed to load Main-Class manifest attribute from
C:\jaxb-1.0-ea\lib\jaxb-rt-1.0-ea.jar
Please help, if you have come across this or similar issue..
Or let me know how you create a .xjs file.
Any idea what is the main file class in jaxb-rt-1.0-ea.jar that creates a xjs file ?
All/any help appreciated. Thanks in advance.

Hi,
You cannot use xjs files with the JAXB Beta RI.
This has been mentioned at http://java.sun.com/xml/jaxb
"Note that this version is not API-level compatible with the previous released version of the specification and DTD schemas are no longer supported."
You can generate code using the xjc binding compiler for schema documents.
Pls let me know if you have more questions
Thanks,
Bhakti
Friends,
I am trying to use JAXB in windows environment. I have
already included rt and xjc jar files in my system
classpath.
I have sucessfully created java files using the xjc
compiler(without the xjs map file). They rock!!
But I am facing problems while creating .xjs file from
my dtd. I tried looking into previously discussed
topics, with no help. :(
my command line:
java -jar C:\jaxb-1.0-ea\lib\jaxb-rt-1.0-ea.jar
mySchemaFile.dtd
This is what i get :
Failed to load Main-Class manifest attribute from
C:\jaxb-1.0-ea\lib\jaxb-rt-1.0-ea.jar
Please help, if you have come across this or similar
issue..
Or let me know how you create a .xjs file.
Any idea what is the main file class in
jaxb-rt-1.0-ea.jar that creates a xjs file ?
All/any help appreciated. Thanks in advance.

Engine having problems loading nested classes

Hi all,
We are having the strangest problem:
We are using PAPI to create an instance of a process by passing a complex class, that we have defined, in the BeginIn argument set. Some classes are loaded successfully by the JVM, others cause the Engine to throw a ClassNotFoundException. Here's an example:
ClassA has 3 members:
ClassA
---ClassB
---ClassC
---LinkedList<ClassD>
Classes A, B, and C are all loading fine. Class D cannot be found.
Here's another example:
ClassA has 3 members, ClassD contains instance of ClassE:
ClassA
---ClassB
---ClassC
---ClassD
---ClassE
Again, Classes A, B, C, and D are all loaded, but ClassE cannot be found.
All classes are in the same JAR file, in the same package, and all are cataloged into BPM under the same directory.
I'm using BPM 6.0.3 on Weblogic 10.0.0.1
The PAPI code is being called from a different server than the engine is running on.
Any ideas why nested classes are causing this kind of problem?
Thanks,
-Ken

OK
Here is another twist to whoever may be reading this thread.
When the EJB containg the PAPI call and the BPM Engine are on the same Weblogic server, the code works fine. When the EJB and the Engine are on different Weblogic servers, the Engine throws the "ClassNotFoundException". It is definitely the remote Weblogic server containing the Engine that is throwing the Exception.
It seems as though the engine and the PAPI code are having difficulty communicating through RMI...

JSPServlet can't load taglib class under W2K

Hello,
iAS version: 10g (9.0.4)
platform: w2k
Service Pack: sp4
I've deployed a custom application. When I try to access to the application I get the following error in the application.log:
JSPServlet: Exception: oracle.jsp.parse.JspParseException: line number 18, <%@ taglib uri="/includes/TTT_TagLib.tld" prefix="ttt" %>
Error: Unable to load taghandler class: /includes/TTT_TagLib.tld
The deploy of the same ear under Linux platform with the same iAS version ( 9.0.4 ) is working fine.
Any idea?

Hi all,
CLASSPATH in windows is D:\oracle\mtierAS10g\jre;D:\oracle\mtierAS10g\jlib;D:\oracle\mtierAS10g\jre;D:\oracle\mtierAS10g\rdbms\jlib;D:\oracle\mtierAS10g\network\jlib;
CLASSPATH in Linux is equivalent

Server could not load the class

I m trying to create a new adapter task bt when i select xliACE.jar from the dropdown box, its trowing an error " Server could not load the class"
Below is the server log--
ERROR,04 Dec 2007 09:18:48,217,[XELLERATE.JAVACLIENT],Class/Method: tcADPClient/introspect encounter some problems : RemoteException occurred in server thread; nested exception is:
java.rmi.ServerError: Unexpected Error; nested exception is:
java.lang.UnsatisfiedLinkError: no ACEUser in java.library.path
java.rmi.ServerException: RemoteException occurred in server thread; nested exce
ption is:
Could any one provide some help
Thanks

Should compile java code with the same jdk as being used by OIM

Generic RMI Loader

Hello,
I'm trying to build a generic RMI loader object, i have for example 2 Remote Objects with 2 interfaces
Interface_A and Interface_B
then in my load code i have to define
private Interface_A objA;
private void someLoadMethod() {
objA = (interface_A) Naming.lookup(some_url);
the idea is to have a class where:
you define a generic objec:
private Object obj;
private Object ifaceObj;
private void someLoadMethod() {
obj = (ifaceObj) Naming.lookup(some_url);
ifaceObj must be the remote object interface..
with this you can load multiple RMI objecs with one class so can i use something like this or try with class.forName and some config files to specify a list of interfaces provided by the server?
hope you understant my question,
Thanks,
Martin Hermosilla

Hello Martin,
If I understand your question, I think I may be able to help.
I host a free software project at Sun's java.net:
https://cajo.dev.java.net
It deals with loading any type of object using RMI, all thorough a single interface. The project site has lots of documentation, examples, Javadocs, and of course full free source code.
I hope it can help you,
John

Error on Desktop: iTunes unable to load data class information from sync services.

Error on Desktop; iTunes unable to load data class information from sync services.

Hi there Randall112,
You may find the troubleshooting steps in the article below helpful.
iTunes for Windows: "Unable to load data class" or "Unable to load provider data" sync services alert
http://support.apple.com/kb/ts2690
-Griff W.

TS2529 iTunes was unable to load data class information from Sync Services. Reconnect or try again later is the error message I am getting when i connect my iphone 4 to my windows based computer. Any help out there?

iTunes was unable to load data class information from Sync Services. Reconnect or try again later. This is the message when I try to connect my iphone 4 to my computer. If anyone could help me with this, I would appreciate it.

iOS: Device not recognized in iTunes for Windows
http://support.apple.com/kb/TS1538
iOS: Device not recognized in iTunes for Mac OS X
http://support.apple.com/kb/ts1591

I keep getting this error message: ITunes was unable to load data class information from Synch Services. Reconnect or try again later. What does that mean? Can I fix it? or do I have to wait for the next update?

I keep getting this error message: ITunes was unable to load data class information from Synch Services. Reconnect or try again later. What does that mean? Can I fix it? or do I have to wait for the next update?

See TS2690: iTunes for Windows: "Unable to load data class" or "Unable to load provider data" sync services alert.
tt2

Was unable to load data class info from sync services. try again later.

Since installing the latest version of itunes (11.1.5.5) whenever I have either mine or my wife's iphones (4 and 5c, both with the latest 7.1.1) turned on and I start iTunes, I receive the error message saying that itunes was unable to load data class info from sync services. try again later.
If I leave the phones turned off and open iTunes, I am able to sync my old ipod so it appears to be an issue with the software on the phones?
I'm just not sure where to start. I've made sure that itunes has the latest version and no more updates are available.
Thanks in advance,
jamey8420

this is on a windows 7 machine, btw.

ITunes was unable to load data class information from Sync Services. Reconnect or try again later.

Ever since I upgraded to iTunes 10.4 I've been getting this dreaded message on many occasions when I try to sync my iPhone 4 or iPad 2 with my Win 7 64 bit machine. "iTunes was unable to load data class information from Sync Services. Reconnect or try again later." What happens is that local content (music, videos etc) will sync properly to my iPhone, but other content (such as Outlook information, MobileMe stuff, etc) will not.
I have uninstalled and completely purged all Apple data from my PC (including hidden files and folders under Common Files and in the Registry) and reinstalled iTunes. Yet after one or two syncs, the same problem resurfaces. The other weird part is that the Sync Services crap-out message will happen after I do a successful sync, leave the iPhone connected to the PC, and don't even touch the computer for several hours.
I've actually developed a very tedious work around that seems to restore syncing if for a short time.
- Undock/unconnect all Apple devices from the PC.
- Close iTunes, MobileMe control panel, and Safari (if you have it).
- Start Task Manager (Ctrl + Alt + Del) and shut down iTunesHelper.exe and SyncServer.exe
- Open up a Windows Explorer window (like My Computer) and under Tools, Folder Options, View, toggle on Show Hidden Files and toggle off Hide Protected Operating System FIles
- In WIndows Explorer, navigate to "C:\Users\<your name>\App Data\Roaming\Apple Computer". Rename the folder Sync Services to something else, like Sync Services_Old.
- In WIndows Explorere, navigate to "C:\Program Files (x86)\Common Files\Apple\Mobile Device Support" and double-click on AppleSyncNotifier.exe.
- Go back to your Folder Options and turn off SHow Hidden Files and toggle on Hide Protected Operationg System Files
Now you can start up iTunes again and connect your device. It should sync properly again (at least, until it doesn't once more).
Does anyone at Apple have any idea about this error or a solution?

I actually spent a fair amount of time on the phone with a senior Apple tech last week. He directed me to this topic:
http://support.apple.com/kb/HT1923?viewlocale=en_US
It's important that you go through the steps EXACTLY as described here and in the proper order. Also make sure MobileMe control panel is uninstalled (if you have it).
Interestingly, when I went through this procedure and then reinstalled iTunes 10.4 64-bit (didn't do MobileMe or Safari at this stage, but QT is automatically installed) everything worked perfectly. The aforementioned error messages disappeared and all is working flawlessly, as it should.
I hope my expereince will help! Give it a try.

RMI - loading a class across a network

Similar Messages

Maybe you are looking for