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Index › Programming Questions & Help › Integration › Using decompiled .jar files
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Using decompiled .jar files (Read 1140 times)
mulder
Using decompiled .jar files
Nov 2nd, 2006, 5:21am  
If someone exports their project as an applet for the web, can you take that .jar file, decompile it and use the code to recreate the project directly in Processing on your local machine? If not, is there any way to get the original code out of the .jar file, without trying to convince the project author to make it available?

Is it possible to use Processing to import the .jar file and parse the code automagically, or could this feature be added?

Mulder
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JohnG
Re: Using decompiled .jar files
Reply #1 - Nov 2nd, 2006, 11:57am  
a: no.
b: theoretically maybe, but not in any nice way, and it's really not a good idea, and it'd probably take you longer to work out what was going on than if you just wrote your own version from scratch.
c: no.

As another issue, the code is copyright the original author, and decompiling it and using it without permission is almost certainly against the law wherever you are.
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mulder
Re: Using decompiled .jar files
Reply #2 - Nov 2nd, 2006, 3:16pm  
The code may be copyrighted if the author invokes that rights, but decompiling it is not against the law. International copyright law still allows for anyone to borrow ideas and concepts from any work.
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JohnG
Re: Using decompiled .jar files
Reply #3 - Nov 2nd, 2006, 3:49pm  
Things are copyrighted unless stated oterwise, the author does not need to invoke anything.

Ideas and concepts yes, code no. You can see the ideas and concepts from the results, which means you don't need to decompaile the .jar file.
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mulder
Re: Using decompiled .jar files
Reply #4 - Nov 2nd, 2006, 3:54pm  
No, the author can claim copyright upon creation, but to actually have it and protect it requires registration with the copyright office.

Ideas and concepts includes code, as there are only a finite number of ways to accomplish the same thing in code. One cannot learn from what they can't see, and therefore they can't use what they learn to do something else. So, if you had to decompile a .jar file to see what was going on, it's perfectly legal.

Mulder
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JohnG
Re: Using decompiled .jar files
Reply #5 - Nov 2nd, 2006, 4:12pm  
mulder wrote on Nov 2nd, 2006, 3:54pm:
No, the author can claim copyright upon creation, but to actually have it and protect it requires registration with the copyright office.


Bzzt, wrong.
http://www.copyright.gov/help/faq/faq-general.html#what

"Do I have to register with your office to be protected
No. In general, registration is voluntary. Copyright exists from the moment the work is created. You will have to register, however, if you wish to bring a lawsuit for infringement of a U.S. work. See Circular 1, Copyright Basics, section “Copyright Registration.” "
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mulder
Re: Using decompiled .jar files
Reply #6 - Nov 2nd, 2006, 4:18pm  
Apparently you just want to argue. As I said, and the copyright office confirms, the author can claim copyright upon creation, but to actually have it, registration is required; otherwise it cannot be protected, even if they had it. Someone else may have claimed and registered a copyright previously for the same thing.

Mulder
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JohnG
Re: Using decompiled .jar files
Reply #7 - Nov 2nd, 2006, 4:33pm  
I do not "just want to argue", you seem to be ignoring what I'm saying because you want to believe what you're wanting to do is right.

I'd have though that "copyright exists from the moment the work is created" is pretty plain, and says that it exists without registration, automatically, without having to be claimed, and the rest of that snippet says that registration is only required IF you want to bring a lawsuit for breach of copyright.

> Someone else may have claimed and registered a copyright previously for the same thing.

You appear to be confusing copyright and patents. 2 people can both draw a simple picture for instance, even if it's of the same thing, and extremely similar, both have copyright of their work, no matter how similar.

It shoudl also be noted that that wonderfully power grabbing law known as DMCA also has things to say about reverse engineering things, which may or may not apply.


Also from a moral point of view, if you've contacted the author and asked for the code and he or she has said no, you should accept this and embrace the challenge of writing your own code to do similar things.

And as a final also, there's a not-insignificant chance that the person who wrote the code you're wanting to get at may be on these forums...
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mulder
Re: Using decompiled .jar files
Reply #8 - Nov 2nd, 2006, 5:08pm  
What I want to do is find out if decompiling a .jar file would help me to recreate something in Processing. If what you said previously is true, then it's not (easily) possible.

Yes copyright exists from the moment of creation, but if the author is not claiming that right, it has no bearing on the issue. If someone were to be in violation of a claimed copyright, you would have to prove the violation, and prior registration would be required; otherwise, that lawsuit is going nowhere. This is why all the original Star Trek episodes from the 1960s are in the public domain; they were never registered with the copyright office, so neither Paramount nor the estate of Gene Roddenberry can make any claim.

No, I'm not confusing copyrights and patents; you can't patent a computer program or any code, but you can copyright a program and unique code. But since there's only a limited number of ways to do certain things in code, those methods can't be copyrighted. DMCA doesn't apply here.

Having contacted the author(s) of the code in question, I've received no reply yet, so I don't have any idea when or if I will get a response, much less what it would be. In the event I never get one, I was simply exploring what other alternatives I would have to try to recreate the project in Processing so I could see it and experiment with it by altering various parameters. The author(s) of those projects may be on the forums, in which case I would hope they would reply to my email; I'm not trying to do anything illegal or unethical.

Incidentally, I did post a response to your reply yesterday about saving or exporting files to .ai or .PDF format here:

http://processing.org/discourse/yabb_beta/YaBB.cgi?board=LibraryProblems;action=display;num=1162397232

and I also sent you a private message asking for an email address so I could email an entire project to you that I also want to get the output in .ai or .PDF format.

Mulder
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JohnG
Re: Using decompiled .jar files
Reply #9 - Nov 3rd, 2006, 10:36am  
Sorry I didn't see the private message, there's no big notification when there's new messages, I've replied now.
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