Why stub and skeleton ?

Hi,
I am new RMI concepts...
i am not able to understand why we need stub and skeleton...
we can can put all the stub codes/operations in our client program itself...
similarly for skeleton...
then why we are having a seperate things like stub and skeletons??
thanks

heloo firend,
stub is gonna be in the client side and skeleton i s gonna be in the server side...
stub is a proxy 4 the remotemethod in the server....

Similar Messages

What is actually stub and skeleton ??????????

Can anyone explain from their own words ...
what is stub and skeleton???????/
avoid saying "search in google..."

avoid saying "search in google..."Why?
But, ok, here you go: http://java.sun.com/j2se/1.3/docs/guide/rmi/spec/rmiTOC.html , chapter 8.

Problem while generating stub and skeleton in ejb

Hi All,
I am learning Ejb,i developed a simple hello world application .And i am trying to generate stub and skeleton for that using weblogic.ejbc.I am getting the following error
C:\nkmb\ejb\HelloEjb>java weblogic.ejbc slb.jar
<Jun 22, 2006 9:55:35 AM EDT> <Warning> <EJB> <BEA-010212> <The EJB 'HelloBean(J
ar: slb.jar)' contains at least one method without an explicit transaction attri
bute setting. The default transaction attribute of Supports will be used for the
following methods: remote[hello()] >
C:\nkmb\ejb\HelloEjb\ejbcgen\examples\HelloBean_gbyfgg_Impl.java:11: cannot a
ccess java.io.Serializable
bad class file: C:\Program Files\Java\jre1.5.0_06\lib\rt.jar(java/io/Serializabl
e.class)
class file has wrong version 49.0, should be 48.0
Please remove or make sure it appears in the correct subdirectory of the classpa
th.
public final class HelloBean_gbyfgg_Impl
^
1 error
Exec failed .. exiting
can anybody help me to getting out of this problem.
thanks inadvance,
nkmb

Try the following forum (about EJB technology)
http://forum.java.sun.com/forum.jspa?forumID=13

Unable to get stubs and skeletons

hai..
im new to rmi..
help me plz...
here i do have four java files..
G:/sen/rmi>
AddServerIntf.java
AddServerImpl.java
AddServer.java
AddClient.java
i compiled these four files
G:sen/rmi> javac AddServerIntf.java AddServerImpl.java AddServer.java AddClient.java
successfully compiled and got class files..
G:/sen/rmi>
AddServerIntf.class
AddServerImpl.class
AddServer.class
AddClient.class
then i wanted to create stubs and skeletons...so i did the below thing..
G:sen/rmi> rmic AddServerImpl
bt im getting below error..
error: Class AddServerImpl not found.
1 error
here i didnt use any packages in these four java files..and i have four class files in G:/sen/rmi>..
did i do any mistakes..?
should i do anything before use rmic....?
plzzz help me..
thanks in advance..

(a) Are these classes in a package? say 'rmi'?
If so, you should be in the directory containing the package when you compile and when you run rmic, and you should provide the fully qualified class name to rmic, e.g. rmic rmi.AddServerImpl.
(b) Skeletons haven't been needed since 1998, and haven't been produced by rmic except on special request since 1.5.

Location of ejbc Utility for generating stub and skeleton in SunONe.

Hi everybody,
I am using Sun One Application Server 7 update 2. Looking for the location of ejbc utility in filesystem for generating stub and skeleton.. Any help regarding this will be appreciated.
Thanks,
Santa

Try the following forum (about EJB technology)
http://forum.java.sun.com/forum.jspa?forumID=13

EJB stub and skeleton code

I would like to examine the EJB stub and skeleton code that OC4J is generating for my applications. Is there a way to do this?

The stub and skeleton code is built into the $OC4J_HOME/application_deployments... The file is called deployment.cache which is a ZIP file of the stubs and skeleton code.

Stub and skeleton generation?

I was looking through the documentation and couldn't find this. Where does the stub and skeletons for an EJB get generated?
When you deploy the archive in the console?
Is there a standalone compiler for ejbs?

Dana,
When you deploy an application (eg, jdbc-simple), then ejbc is done on the fly by the deployment backend. In addition, a client jar is created and placed in $INSTANCE/applications/j2ee-apps/jdbc-simple_1/.
You can also retrieve the client jar during deployment by specifying the "--retrieve" option of "asadmin deploy". For more information, type "asadmin deploy --help"
Thanks,
- deepak

Stub and Skeleton

what does it mean "Stub and Skeleton"
No, i am not asking for dictionary meaning . but in terms of programming . what it means ?
can you explicitly ( an example will be be good ) explain what does it mean in programming ? thanks for the time

ceil,....thanks for the answer .
but u have already implemented method :)it's technically implemented, but logically it doesn't yet do what it is supposed to.
stubs are usually generated by a tool or another developer (, who may also be a tool.).
i am not able to get you properly. ..so can i call
like below ?
Stub
interface ABC
void someMethod(); // not implemeted bcoz its
interface
}No, an un-implemented method like that (or abstract) is not]/b] called a stub. a stub only refers to "logically" unimplemented methods.
OR do u want to mean a set of Stub is a skeleton ?Yep :)

Stub and skeleton for local EJBs

is there a stub and skeleton for local EJBs ?

Not in the traditional sense in that there is no marshalling/unmarshalling for EJB local invocations
since they have pass-by-reference semantics. However, the actual implementation of the
EJB reference is not exposed to the application, so in practice the Java EE vendor can have
whatever artifacts it wants under the covers. Like all EJB invocations, the Local EJB client
holds a special reference object that is distinct from the bean class instance itself.
--ken

RMI, stubs and skeleton and EJB

HI,
IN RMI we copy stub on client machine and skeleton on Server machine.
EJBs are said to be extension of RMI.
In EJB when we deploy EJB on the app Server server generates stubs and skeleton.
But on the client machine we don't copy any stub.
So from where these stubs (home stub and remote stub ) comes on client machine because we only depoly the EJB at server and then use that from client
Can anybody explain this ?
Thanks,
Ankur Mittal

Hi,
A number of these answers are correct. The thing to keep in mind is that the entire issue of RMI stubs and the mechanism by which those stubs are made available to the runtime code(whether that code is running in a J2EE server or a client) is vendor-specific. One important thing to note is that these generated artifacts are not present in a portable J2EE archive (.ear, ejb-jar, .war, etc.)
If needed, they are generated at some point by the J2EE implementation. Some vendors expose tools that generate these artifacts. The original J2EE 1.4 SDK beta release had such a tool called j2eec.
Alternatively, many vendors generate them as part of the deployment stage itself. In that case, it's typical for the deployment process to produce some output file that contains the generated artifacts. This is the approach used in the current J2EE 1.4 SDK. The output file is usually referred to as a client.jar. The stubs are automatically available to any code running within the server, but client applications that need them must somehow make the client.jar available to the client JVM. For Application Clients, this is done by specifying the client.jar as one of the input arguments to the runclient command. For stand-alone clients, the client.jar is simply added to the user-classpath when starting the JVM.
Some vendors also support automatic stub-downloading. This has the advantage that the stubs don't have to be available to the client classpath when the client starts. The downside is that using automatic stub downloading requires that a security manager be installed in the client JVM. That typically isn't an issue for the Application Client container, but many stand-alone clients are not coded to instantiate a security manager.
Yet another approach is to dynamically generate the stubs within the client code itself. This is one of the best options since it completely removes the notion of stubs from the developer's view. It's too bad this wasn't done from the beginning, since stub configuration is one of the most common errors encountered by EJB developers. In addition, the static generation of such artifacts is often a deployment-time bottleneck. Finally, note that the EJB Remote view is only one of many J2EE technologies that potentially require such generated artifacts. E.g., web services implementations typically rely on some of the same mechanisms to marshall and unmarshall requests.
--ken
Kenneth Saks
J2EE SDK Engineering
SUN Microsystems

Stubs and Skeletons

I am struggling to understand RMI quite a bit, and what I am looking at just now is Stubs and Skeletons. I was hoping that someone could help fill in the gaps for me. Here's what I (think I) know:
The RMIC compiler creates Stubs and Skeletons
The stub acts as a proxy for the server object
The skeleton acts as a proxy for the remote object
The stub serialises parameters, and passes a byte stream to the remote object
It deserialises the return value for the server
The skeleton deserialises the inputs to remote objects
It serialises the return values
Any help would be greatly appreciated. If the above is complete garbage - just let me have it! lol

The stub acts as a proxy for the server objectCorrect. At the client.
The skeleton acts as a proxy for the remote objectNo. There is no difference between 'the server object' and 'the remote object' so this explains nothing. The skeleton was used to mediate between the incoming call stream at the server and the remote object, by calling its methods: prior to the introduction of reflection, you needed a piece of generated code to do that, that knew about the actual remote methods and signatures. Since 1998, reflection has been used to do that. So in reality you don't need to worry about skeletons at all.
The stub serialises parameters, and passes a byte stream to the remote object
It deserialises the return value for the serverCorrect.
The skeleton deserialises the inputs to remote objects
It serialises the return valuesCorrect, and it also calls the appropriate method in the remote object (which by this time is a local object in the same JVM).
But skeletons are just a historical curiosity now.

Problem creating stub and skeleton.

C:\RMI\PRODUCT>rmic JDBCProductImpl
error: Invalid class file format in .\JDBCProductImpl.class. The major.minor ve
rsion '49.0' is too recent for this tool to understand.
error: Class JDBCProductImpl not found.
2 errors
C:\RMI\PRODUCT>
what's wrong??
could somebody please tell me?thanks in advance.

You are using a higher JDK version for compiling your class than what the rmic is expecting. Try using javac -version "1.x" FileName.java while compiling. And don't forget to specify something for x (4 should work).

RMIC compiling the server to get the stub and skelton problem

i have this problem
i'm new to RMI
and i tried to simulate the same interfaces and class in the RMI java tutorial and when i tried to use rmic to create the stub and skeleton i didnt get any thing
my RMI server application is called
c:\samplestep\ServerAPP\ServerEngine.java
and i complied this java file with
c:\samplestep\ServerAPP>javac ServerEngine.java and it works well
i have d:\jdk1.3
and i have D:\ORANT\jdev(which is Oracle JDeveloper IDE)
my classpath system variable (windows 2000 professional)
Looks like this
D:\jdk1.3\bin;D:\jdk1.3\jre\lib\rt.jar; some other paths;
c:\samplestep\ServerAPP;
D:\ORANT\jdk\bin;D:\ORANT\jdk\jre\lib\rt.jar
and at the command line prompt i wrote
c:\samplestep\ServerAPP>rmic -d c:\samplestep\ServerAPP -classpath c:\samplestep\ServerAPP\ServerEngine
and the result was the help associated to the rmic command
and no stub or skelton class are generated
could any one help me please(required urgently)
my email is [email protected]

Hi Batal,
Did you follow all the steps required to create a RMIServer and RMI Client.
Step1: Define an interface(IRMIInterface) that extends Remote
Step2 : Define a class(RMIServer) that implements extends UnicastRemovetObject and extends IRMIInterface
Step3 : Compile the IRMIInterface.
Step4: Compile the RMIServer.
Step5: Try RMI compile.
If you have tried all these, just verify whether the class files are there, before you do rmi compile.
You could have got some errors while compiling, why cant you post them
LathaDhamo

Stub and Naming Service

While registering a remote object with a naming service, for example, Naming.rebind("MyService", remoteobj),the stub gets registered and that stub is sent by a registry to a client in response to Naming.lookup(""MyService). Then client becomes able to call method remotely. I tried a example in which I did not bind a remote object and I had a stub on client. And at client I created an object of stub class and invoked a remote method but it did not work. Why it is necessary to have a remote object bound to registry at server, because it ultimately binds stub and that stub is sent by a call (Naming.lookup("MyService")). To me the only requirement is to have a stub at client side to make remote calls. Is there any additional information sent by a registry to a client in addition to sending a stub in a rsponse to callNaming.lookup("MYService") which isneeded at client for calling remote method on stub. Another point is that Stub needs to know the IP address and port no. to be able to talk to listening service on remote jvm for execution of methods there, but when I decompiled the stub, I did not find anything like that. I would be thankfull to you if you provide me a clear picture of what I have asked for.
Thanks in advance

Since you have no clue what remote procedure calls are all about, I would suggest you take the tutorial on RMI. This should answer all your questions.
Additionally, you should also take a lesson in using separate paragraphs when writing.

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Note that the backup that iTunes makes doe not include media.
To move mdia to the new computer see:
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Why stub and skeleton ?

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