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failed developer certification

 
Chris Lee
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Hi Guys,
I just got my test result today, and I found out I failed the developer certification because grader said my server failed to start. I tried testing my server following my own steps in my readme and was able to start the server! What should I do? Any suggestion is appreciated!
thanks
Chris
 
Andrew Monkhouse
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Hi Chris,
Step 1: Give your application to someone who is not technical and see if they can start it following your instructions. Do not say a word while they try it - just watch and see if they misinterpret something you wrote.
Step 2: If possible, give your application to someone who is experienced at breaking software and see if they can think of some way to follow your instructions and still have it not work. An example was another post on this board where someone mentioned getting a command prompt and entering the command "java -jar server.jar" without first changing to the uninstall directory or setting a class path. I could find a way to break those instructions.
Step 3: If all else fails, post the relevent part of your instructions here so we can critique it.
Step 4: If you managed to get agreement that the server does work following your instructions, then write to Sun and ask for it to be reviewed as the server does start when your instructions are followed.
Regards, Andrew
 
frank sun
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Sometimes, when the server changes to another machine, we should modify the file java.policy, so as to allow the client to connect to.
Should the program modify the file java.policy automatically whenever the server changes it's server and port?
Regards!
Frank
 
Andrew Monkhouse
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Hi Frank,
Do you really need a policy file? My applications seem to work just fine without one.
If you do need one, then I suggest you provide a policy file that does not need changing, such as:
grant {
// Allow everything for now
permission java.security.AllPermission;
};

And then make a comment in your documentation stating that the provided policy file is insecure and should be modified for production use. Then give an example "secure" policy file in the documentation.
That way you have covered the fact that this policy file allows too much access, but you have not caused yourself problems with providing a policy file that might cause your program to fail.
Regards, Andrew
 
Mark Spritzler
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No need for a policy file, because there is no need for an RMISecurityManager.
Mark
 
frank sun
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Originally posted by Mark Spritzler:
No need for a policy file, because there is no need for an RMISecurityManager.
Mark

But when I remove the policy file from the working directory, the program show error message like 'connection refused...'.
So, how do you make it without the java.policy file? do I need to add any special code in the program?
Regards!
Frank
 
Chris Lee
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Thanks for the advice. I think I'll try letting someone follow my procedure in the readme to see if anything might cause the server fail to start.
By the way, what is the email address I should send to if I have to email Sun regarding this issue?
 
Mark Spritzler
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Frank you must remove your RMISecurityManager from your code.
Mark
 
Andrew Monkhouse
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Hi Chris,
From the instructions in the new assignments:
If you feel you must ask your question, you should address it to who2contact@sun.com. Clearly indicate that the question relates to the Sun Certified Developer Exam, provide your candidate ID number, name, and include your return email address in the body of your message. Describe your issue as briefly as reasonably possible; you will be asked for more information if necessary.

Regards, Andrew
 
frank sun
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Originally posted by Mark Spritzler:
Frank you must remove your RMISecurityManager from your code.
Mark

Hi, Mark
I don't have any RMISecurityManager in the code(RMIFactoryImpl) when binding the service.
Could you detail it more?
Regards!
Frank
 
Barry Gaunt
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Originally posted by Chris Lee:
Thanks for the advice. I think I'll try letting someone follow my procedure in the readme to see if anything might cause the server fail to start.

Chris, did you ever take a Sun Java programming course, one with an instructor from Sun? Sometimes they give their e-mail addresses for contact after the course.
If so, you could try to contact him/her to referee the issue. If you can prove to them your server will start then you have a better chance to get an appeal through to the SCJD developers. Dunno, just an idea.
-Barry
 
Mark Spritzler
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Originally posted by frank sun:

Hi, Mark
I don't have any RMISecurityManager in the code(RMIFactoryImpl) when binding the service.
Could you detail it more?
Regards!
Frank

Simply put a policy file in conjunction with a SecurityManager is what returns connection refused type errors. So if both are removed then you will have all access.
I had no policy file or security manager, the startup was;


and


No policy, no security manager.
Somewhere either in your code with a SecurityManager or in your command line specifying a policy file you have something there that is causing this error. Or maybe you are giving the wrong IP address for your client to connect to the server.
Mark
 
frank sun
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Hi, Mark
I forgot to remove the java.policy file in the directory, for now, it works.
Thanks a lot!
Frank
 
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