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Java Forum / General / March 2007How to create a JAR that contains only the class files needed
Hello all, I'm sure this has been asked before but I could not find it... is there a program out there that will create a JAR file that only includes the class files needed by the main class to run? Thanks in advance! > Hello all, > [quoted text clipped - 3 lines] > > Thanks in advance! I write a batch file to do that every time I create a new project. It is really pretty simple to do. I even have it clean up the class files and editor backup files.  SignatureKnute Johnson email s/nospam/knute/ On Mar 13, 9:39 am, Knute Johnson <nos...@rabbitbrush.frazmtn.com> wrote: > > Hello all, > [quoted text clipped - 12 lines] > Knute Johnson > email s/nospam/knute/ No, really a tool like a java profiler or something that can see which classes are loaded and used while running an application. So for example I include log4j or xerces but I don't use every class from there while running my application. So the question is if there is an application which can slim down, or make a list of actual classes that are used by a cirtain application. Thank You, Kuki Szabolcs On Mar 13, 9:39 am, Knute Johnson <nospam@rabbitbrush.frazmtn.com> wrote: > > Hello all, > [quoted text clipped - 12 lines] > Knute Johnson > email s/nospam/knute/ Please let me know if you find an answer to this question. I was thinking that it would require a profiler like JRat or something like that to create a list of classes that were loaded, during the application run. Then rebuild the jar file with only that list of file. Of course this method is somewhat dangerous because the application has to be tested with all the possible code paths. Because you might have somewhere new Class("com.xxxx").newInstance() call which otherwise is not mapped. > On Mar 13, 9:39 am, Knute Johnson <nospam@rabbitbrush.frazmtn.com> > wrote: [quoted text clipped - 23 lines] > have somewhere new Class("com.xxxx").newInstance() call which > otherwise is not mapped. I don't keep .class files laying around in my package tree. I only compile the classes I need for my application and then I delete them. I never have extra classes in my .jars. SignatureKnute Johnson email s/nospam/knute/ > On Mar 13, 9:39 am, Knute Johnson <nospam@rabbitbrush.frazmtn.com> > wrote: [quoted text clipped - 23 lines] > have somewhere new Class("com.xxxx").newInstance() call which > otherwise is not mapped. The easiest way I can think of is to use the -verbose:class option at runtime and see which classes are listed as loaded. >> Please let me know if you find an answer to this question. >> I was thinking that it would require a profiler like JRat or [quoted text clipped - 7 lines] >> have somewhere new Class("com.xxxx").newInstance() call which >> otherwise is not mapped. Java classes are always loaded lazily. Even wthout reflective calls, different code paths can result in different classes being loaded. > The easiest way I can think of is to use the -verbose:class option at > runtime and see which classes are listed as loaded. If you want to do it reliably, you'll need to analyze the class files and see which classes they reference (recursively, of course.) This is non-trivial. >>> Please let me know if you find an answer to this question. >>> I was thinking that it would require a profiler like JRat or [quoted text clipped - 17 lines] > see which classes they reference (recursively, of course.) This is > non-trivial. The problem with doing it like that is that one needs to analyze dead code instead of just the referenced class files. I figured it would be quite rare that someone has classes that they don't use at all in the code, instead the extraneous classes were referenced in unused (but still compiled) code. >>>> Please let me know if you find an answer to this question. >>>> I was thinking that it would require a profiler like JRat or [quoted text clipped - 23 lines] > code, instead the extraneous classes were referenced in unused (but > still compiled) code. They you'll need to exercise all of the code paths; guaranteeing that would be tricky at best. On Mar 13, 11:30 pm, "Mike Schilling" <mscottschill...@hotmail.com> wrote: > >> Please let me know if you find an answer to this question. > >> I was thinking that it would require a profiler like JRat or [quoted text clipped - 17 lines] > see which classes they reference (recursively, of course.) This is > non-trivial. Actually, it is not that hard. There is a library called ASM from Objectweb that parses the class files. It is quite easy to create the dependency graph from this. I wrote a program for the OSGi headers that makes a dependency graph but this is based on packages, not classes (OSGi is very focused on seeing a package as a first class citizen). The program is currently not creating the payload of the jar from this tree but that would be quite trivial to add. You can download the code from http://www.aqute.biz/repo/biz/aQute/bnd/0.0.115/bnd-0.0.115.jar. The source code is in the JAR in the OPT-INF/src directory. This program actually has its own class file parser. Kind regards, Peter Kriens > Hello all, > [quoted text clipped - 3 lines] > > Thanks in advance! I will tell you a way to create a Executable jar First write a Manifest.mf file with contents as Manifest-version:1.0 Main-Class:Hello then create the archiving using the jar command jar cmf Manifest.mf Hello.jar Hello.class if you don't give java file then no problem All the best.... On Mar 13, 3:43 pm, "sivasu.in...@gmail.com" <sivasu.in...@gmail.com> wrote: > > Hello all, > [quoted text clipped - 14 lines] > > All the best.... Yes, that is a good way to create an executable jar file, but what we would like is to have an application that would analyze which classes are needed by a main function. For example: when we have a source tree of 2000+ files and we create another main class which might use only 1% of this code base, then it would be nice to have an application that could detect which classes are used by that newly created java/main class. And this way be able to have a jar file with only 40 files instead of 2000+. Hope this is clear enough ... > I'm sure this has been asked before but I could not find it... is > there a program out there that will create a JAR file that only > includes the class files needed by the main class to run? Many obfuscators have this feature (it comes almost for free as a side effect of the analysis an obfuscator has to do anyway). E.g. ProGuard. Some links: http://jarg.sourceforge.net/ http://www.alphaworks.ibm.com/tech/jax/ http://www.e-t.com/jshrink.html http://proguard.sourceforge.net/ http://www.fightingquaker.com/jaropt/ Note: I haven't so much as downloaded /any/ of those packages. -- chris On Mar 13, 6:08 pm, "Chris Uppal" <chris.up...@metagnostic.REMOVE- THIS.org> wrote: > > I'm sure this has been asked before but I could not find it... is > > there a program out there that will create a JAR file that only [quoted text clipped - 14 lines] > > -- chris Great Thank You, Many Thanks :) PS: here is something nice for you :) http://www.youtube.com/watch?v=is8bR6UtqxA >> I'm sure this has been asked before but I could not find it... is >> there a program out there that will create a JAR file that only [quoted text clipped - 3 lines] > side effect of the analysis an obfuscator has to do anyway). E.g. > ProGuard. Note that these probably won't work when classes are loaded reflectively, e.g. using Class.forName(). They certainly won't work when a simple static analysis won't reveal the name of the class to be found. "Bryan" <BTRichardson@gmail.com> wrote on 12 Mar 2007 21:54:10 -0700 in comp.lang.java.programmer: >Hello all, > >I'm sure this has been asked before but I could not find it... is >there a program out there that will create a JAR file that only >includes the class files needed by the main class to run? Check this: http://www.bmsi.com/java/ZipLock.java SignatureCheck out QueryForm, a free, open source, Java/Swing-based front end for relational databases. http://qform.sourceforge.net If you're a musician, check out RPitch Relative Pitch Ear Training Software. http://rpitch.sourceforge.net > I'm sure this has been asked before but I could not find it... is > there a program out there that will create a JAR file that only > includes the class files needed by the main class to run? javac will automatically compile any source file for which it needs the class file (so long as you use the correct file names). So do a fresh build specifying only the main class and any other class you use through reflection or other means (services, for instance). javac will compile those files that you need. Bob is now your mother's brother. Tom Hawtin ... > ...is > there a program out there that will create a JAR file that only > includes the class files needed by the main class to run? The JVM itself (at runtime) can act as the program which determines the classes required. If the application is deployed using JWS, and the packages* broken into separate parts and specified as 'lazy' downloads, not only will the minimum classes be downloaded for the application, but should the end user go into a part of the program that requires classes that are *not* cached locally, the classes will be downloaded, cached, and made available to the JVM before proceeding. * I Think it can also be done for individual classes, as well as packages. Andrew T. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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