RMI exception

You have not generated stubs for the server class. You need to do:

rmic fullClassName

Then start the rmiregistry service. And then try to start your server application.

>> can i run the RMI client from JSP ?

You mean a JSP talking to the server using RMI? That should be possible.

http://www.javaalmanac.com/egs/java.rmi/DefineRemote.html

Have a look at the "related examples" as well.

so each time u create the stub file, you need to copy it over to the client as well.

hi,
sorry for late reply.
i have done it myself.
i did not check mail so i could not reply .

i took the help of the "Complete Reference"by  herb schield . i followed all the steps there and it started working immediately. the steps were very easy to understand and comfortable.

i want to close this question

What exactly was the problem? I mean - what were you missing last time? As far as I know, you had not generated stubs.

>As far as I know, you had not generated stubs

yes. correct.

i opened my books and found all the steps information and followed steps.
anyway,

 will you please tell me, what are the files need to copy to the client. i did it blindly. i dont understood it.
i copied...a)_stub file (b) client class file  and (c) serverinterface

if i use more additional classes(may be beans, ) should i copy that too ?

what to copy and waht not to copy is a dilema till now.

of course, my application is running but i am not cool. i have some hesitation about what to copy and what not to copy to the client.



and one more question :

after rmic fullclassname...i got a stub and a skel file....wha are these guys ?



thanks for the response.
please respond.

you just need to copy the interface that you extends Remote, and the stub file.
that's it.

I'm sure you have an interface that look like this:

public interface XXX extend Remote{
    public void dosth() throws RemoteException;
}

right?

just copy this over to the client side along with the stub file.

>>after rmic fullclassname...i got a stub and a skel file....wha are these guys ?
RMI uses a remote object's stub class as a proxy in clients so that clients can communicate with a particular remote object.
The client communicate with the server through stub file(s).

btw, which version of Jdk you are using?
if you use the latest version of jdk, you won't get a skel file anymore. ;-)

>if you use the latest version of jdk, you won't get a skel file anymore
but i am getting  skel !! ....my java version is 1.4.


i am also surprised why other tutorials  talks too much about security !!...there was no security, no java  policy ...nothing involved. does it mean those tutorials are wrong ?


yes. thanks...i am going to split the points

>> my java version is 1.4.

1.4 will still give the skel. 1.5 will not give them.

>> does it mean those tutorials are wrong ?

No. Security is the next step. It comes after you have done the basics.

>>but i am getting  skel !! ....my java version is 1.4.
ok, well, i'm not sure since which version skel is no longer being created. ;-)
i'm using 1.5

security might be an issue when you develop some commercial application. but if you are learning, you can put that a side and concentrate on the RMI structure.

You will discover that RMI is fun! ;-)

mayankeagle is fast....

:)

right now, i  copy the files  to the client machine. and then i invoke remote method and the remote method works.
everything is fine.

 >Security is the next step
>security might be an issue when you develop some commercial application
i am confused.

my  application is running on 1099 port. do u meant to change port to 2000 ? is that u mean by security ?

i did not mean that . i mean sometimes i have noticed to run the RMI  application
with -Djava command and java policy . so, its a peculiar  things to me, i tried to use -Djava command and java policy file but that did not worked.


However,

i) even  if i use so called "Security" do i have to copy files ? or copying files is always ?
2)can u tell how do i use this security ?

>>my  application is running on 1099 port. do u meant to change port to 2000 ? is that u mean by security ?
no.

about security, follow this link ( a bit outdated i guess, but provide the info)

http://www.ccs.neu.edu/home/kenb/com3337/rmi_tut.html

www.purpletech.com/talks/RMI.ppt - mentioned bout stub-skel, security..

You need permission to connect to the particular ports, etc - those aspects are covered in security. Those topics get more complicated when you are connecting to remote servers behind fire-walls, etc

hi, i need some time to read those tutorials. both of you have helped me a lot.  i'll come back

hi,i read in PPT provided by you,
this line...
"Registry VM needs to be able to find stub file(s).You must set the CLASSPATH to include the directory containing the stub file..."

very strange . you know, i did not do it. but still my application running !!...surprising.
my RMI class file is in c:\RMICODE\packages\classes


and i started the rmiregistry from c:\start rmiregistry


the application running perfectly !!.

you see i did not use any -classpath option while running rmiregistry.

is that statement in the PPT wrong ?

the PPT says...

Creating an RMI Client
=======================
Install a Security Manager




System.setSecurityManager(
      new RMISecurityManager());
Adder a = (Adder) Naming.lookup("adder");

int sum = a.add(2,2);
System.out.println("2+2=" + sum);


just this much !!  so, if i want the security then i should add this ..

System.setSecurityManager(
      new RMISecurityManager());


to my client code. rest is same . is that all ?



but in another tutorial(http://www.ccs.neu.edu/home/kenb/com3337/rmi_tut.html)...they are talking about -Djava & policy file and so many things.


i am confused what to do and what not to do.







can you please tell me the steps ?

here i am starting the steps.


STEP1 : i should add System.setSecurityManager (new SecurityManager()); in my client code. is this correct ?


STEP2: How do i compile now ? whats the command ? my RMI codes are in e:\rmicode\com.web packages

STEP3: How do i run my client now ?


please provide a clear example otherwise its going to be difficult to understand.

i appreciate your help.

Thank you

 

>> hi,i read in PPT provided by you,
>>this line...
>>"Registry VM needs to be able to find stub file(s).You must set the CLASSPATH to include the directory containing the >>stub file..."

>>very strange . you know, i did not do it. but still my application running !!...surprising.
>>my RMI class file is in c:\RMICODE\packages\classes
you might have done that without you realize it ;-)
it is actually the same thing with setting the classpath for your java class so that your jvm can find them.
if you are using IDE, the IDE might have set the classpath for your java classes for you.


>>is that statement in the PPT wrong ?
no. you dont need to specify the classpath when u are running registry. you only need to specified it when you run your java code.

The default security manager uses a policy that is defined in a collection of policy files. For the locations of these files see the documentation of the policytool program. If one wishes to grant additional permissions, then one can specify them in a policy file and then request that they be loaded using options such as the following:

java -Djava.security.manager -Djava.security.policy=policy-file MyClass

so,
System.setSecurityManager (new SecurityManager());
should be enough.

Here's a brush-up on classpath: http://www.mindprod.com/jgloss/classpath.html

>For the locations of these files see the documentation of the policytool >program.

where this policy file resides in j2sdk 1.4 ? is it inside "lib" folder ? is it inside "bin" folder  or where is the location ?...i want to see those policy files. i am very much curious about the content of those files.


>java -Djava.security.manager -Djava.security.policy=policy-file MyClass

who will run this command ?

only client ?

only server ?

server and client both ?

excellent ratings to you