Corrupted Class File - what exception to expect?

Hi all,
Does anyone know what type of exception to expect in case of a JVM trying to access a corrupted class file?
Lets say ftping a class file to a unix box in a text or something stupid like that.
Thanks
D

java.lang.ClassFormatError

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$1.class files - what are they?

This is probably a really dumb question, but here
goes....
Having written an applet, I used the deployment wizard to create
a jar file, and moved this on to a web-server. When I open a
HTML document which attempts to call the applet, I get a
ClassNotFoundException, the class in question being my applet
class name, but with a "$1" suffix on the name. I noticed that a
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anyone know what this is for, and how to get round this
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Thanks, Rich
null

JDeveloper Team (guest) wrote:
: Hi Rich,
: I haven't seen this one before. I asked around in QA and they
: weren't aware of it either. Could you provide some more info
: that might help us track down the source of this problem:
: What is the name of the file as it appears in your project?
(the
: .java file), and what exactly is the name of the .class file
that
: is being generated (<filename>.class$1?)
: Thanks for the additional information.
: -L
: Rich (guest) wrote:
: : This is probably a really dumb question, but here
: : goes....
: : Having written an applet, I used the deployment wizard to
: create
: : a jar file, and moved this on to a web-server. When I open a
: : HTML document which attempts to call the applet, I get a
: : ClassNotFoundException, the class in question being my applet
: : class name, but with a "$1" suffix on the name. I noticed
that
: a
: : file of this name has been created in my JDeveloper
"myclasses"
: : directory, and has also been deployed in the jar file. Does
: : anyone know what this is for, and how to get round this
: : problem? Any help would be much appreciated.
: : Thanks, Rich
They are the files with the inner classes of main class, i
think..... if you have a "pp.java" with a inner class ( such a
event listener or something like this), you obtain to files
"pp.class" and "pp$1.class", hope this helps...
Regards, Ignacio Ortega
null

Corrupted QT file - what went wrong?

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Pls help I got following error while executing class file.
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Edited by: Mubin_Attar on May 19, 2008 6:34 PM

Mubin_Attar wrote:
Pls help I got following error while executing class file.
Exception in thread main java.lang.NoClassDefFoundError : main
Edited by: Mubin_Attar on May 19, 2008 6:34 PMIt appears that you typed "java main" or something like that, which means you have a file named "main.class". This is telling you that you don't have such a file.

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ejp wrote:
Once it is on the web host server, anyone can have access to it.That's not true. You're off on the wrong track before you even start. You need to acquire a proper understanding of a web server and its configuration. Your problem can be solved via correct configuration of the server. Nothing to do with obfuscation.So your telling me that once I've uploaded all my .class files and everything else to my host provider, that the people running the server do not have access to it? I find this hard to believe....
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Hi,
I have installed J2SDK1.4.2_03 in D: drive in folder JavaApplications.
Have appended the path: ;D:\JavaApplications\bin in System Variable.
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Error message appears:
Error: could not open C:\Program Files\Java\j2re1.4.2_03\lib\i386\jvm.cfg
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You are right. The older version is being found first. After removing the older version I can run the .class file.
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If you have two public class in a java file what will be the error ?

Q:If you have two public class in a java file what will be the error and how will you remove that.?

Kannan_S wrote:
I dont want you to be on that list . Here goes my explanation..
A class is well defined with members and functions
An abstract class is not defined well as compared to a full fledged class (talking more generically)
An interface is more abstract.
I was asking the author who has posted this question to be like a class(very clear)
and not either as an abstract class or an interface
Hope i have made it clear..Not in the slightest. This has absolutely no bearing whatsoever on the question asked. Not to mention that classes are classes, and all equal in the eyes of the compiler, be they abstract, concrete or interfaces. It's difficult to see what your point is, to be honest, but I suspect it wouldn't be worth seeing anyway

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every time i want to update my phone, i see an alart message saying that the firmware file is corrupted...what do i do now....i am using 5.1.1 and it is jailbroked.......i face the same problem while restoring......plz help.....TOUFIQ

Jailbroken phoned are not supported here. Anything could be wrong with it - it is jailbroken.

DrClap, schapel, jschell whats better architecture jar files or class files

What would be a better architecture for deployment. Jar files or class files. We were recently having a debate at work as to generate installation scripts that put jar files on the system where the app is being installed or to make the script generate class files at the desired location.
It would be good to know as to what you ppl think and what are the pros and cons of both.
Some claimed with class files it would be easier to put in patches later on and I kinda agree with that. However your thoughts would be appreciated.
Come on DrClap, schapel, jschell, jsalonen....... I am a fan of yours already

This, of course, is why topics shouldn't be addressed to individuals - they are likely to never see it. Today is the first time I have seen this, and that is due solely to a search that I was running.
Why would you use one over the other?
----Distribution costs
It takes more time to send a bunch of class files down the wire than a single jar file. However, it takes more time to send a jar than a single class file. So there is a delicate trade off in a web application where one is using java. If you send the jar every time it is modified the entire jar must be moved. Class files take less time, but all of them must be moved for a new person.
So in this case if you have a fixed based of users (internal use), and a majority of the files do not change then class files are better. If the user base is transitory and large (external use) then a jar file is probably better.
----Usage:
You can use reflection to dynamically add functionality to an application. If you use a jar file then the application must be restarted for the changes to take effect. If you use class files then the application does not have to be restarted. Obviously the second only works if you have some way to dynamically notify the application that new classes are available - like a database.
This becomes very relevant if you do not want to restart the application and you do not have a distributed application base in place.
Also the older classes, even if not used, are still loaded in the application unless it is restarted (presuming a class loader is not used.) Most of the time this does not make difference.
Since in the above it is likely that there is not a large distribution problem, when the usage is a concern then the best strategy is as class files. They allow the most flexibility and there is unlikely to be any concern at all how it is packaged.
-------Misc
Speed. Someone suggested speed. Guessing I would say that the jar file is going to be faster. Once the Sun jvm gets the file it doesn't let go. And as pointed out opening files is rather costly. However, I doubt this is going to be a significant cost on any system. Startup costs, although sometimes annoying, are seldom significant in terms of application performance.
Security. The is a certain level of security with a jar file. You have one jar file and distribute it to the help desk people. And one of them deletes it accidently. It is going to be a lot easier to figure that out than if they deleted one class file. Additionally it is probably easier to encrypt/decrypt a jar file (if you really must) than class files.
Dynamic class loading. If you are storing classes in non-traditional places, like a database rather than files, then it is probably going to be easier if you do it as class files.
Testing. It is easier to replace a class file in a testing environment to fix a bug than a jar file. Particularily if the make process for the jar file rebuilds everything.

I followed your help directions on "Corrupt extension files" under "Unable to install add-ons", foolishly deleting the files you told me to. Now firefox won't open. I tried reinstalling firefox but it still won't open. Now what do I do?

I was trying to install the SEOQuake add on. After clicking install Firefox would hang up saying the script had timed out and asking if I want to stop it or continue. Didn't matter which option I chose nothing would happen. The only way to stop it was to close Firefox and restart. Tried restarting the computer. Still wouldn't install. Tried installing the Outwit add on and got the same error leading me to conclude it was a problem with Firefox, not the add on. I found this help page <http://support.mozilla.com/en-US/kb/Unable+to+install+add-ons?s=addons+won't+install&as=s> and did everything it told me to. Finally at the end I got to "Corrupt extension files". I foolishly deleted the files you told me to and now Firefox won't even start! I tried reinstalling Firefox and it still won't start. Tried restarting the computer. I have no idea how to get back to where I was let alone install the add ons I wanted to install. Please help. At this point I'd just be happy to be able to get Firefox working.

See [[Troubleshooting extensions and themes]] and [[Troubleshooting plugins]]
You can use "Disable all add-ons" on the [[Safe mode]] start window to disable all extensions.
Create a new profile as a test to check if your current profile is causing the problems.<br />
See [[Basic Troubleshooting#Make_a_new_profile|Basic Troubleshooting: Make a new profile]]
If that new profile works then you can transfer some files from the old profile to that new profile (be careful not to copy corrupted files)<br />
See http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Corrupted Class File - what exception to expect?

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