I am using eclipse IDE and want to edit the attached source file of the jar file. For doing this i downloaded the src.zip and attached the file, but it is opening as a .class though I am able to read the file (which is a .class file) but i also want to edit the file.
Why I am not allowed to edit it? how to open an attached file with .java extension not .class extension.
thanks in advance
That's not possible. In order to edit the source, you have to unpack the JAR and create an eclipse project, from which you can then create a JAR with the modified code.
Because you have to link it... Source files are not tied to compiled classes in jar, so if you edit it, nothing will happen to the jar file
You have to create a separate project in Eclipse, and rebuild the jar with your modifications
.class files are not readable by human being unless you decompile it. Many decompilers exist. Carefull about what you are allowed to do and what you aren't, though...
Usually, .java aren't in .jar.
Related
I have a .jar file and When I extract it, It gives me all the .class files present in that jar file.
I have decompiled all the .class files using http://jd.benow.ca/ tool but i want that all the .class files should save into .java files.
Right now i can see only the code but extension is not converting to .java.
Anybody Please help me in this.
you can use javadecompilers and its works perfectly
and in the next step you decompile with Upload and Decompileand this page be showing
and thats is just copy the package folder from the jarname.zip and paste it in you project.
i tested its work for me .
you can see this answer for more.
jd-cmd
https://github.com/kwart/jd-cmd
works fine for decompiling. I used it to convert whole jars into source code. Look up the command line options for more details, e.g. --outputDir for specifying a directory for the generated source code.
How can I edit code in a .class file in a .jar file using Android Studio? I have already tried to edit it of course. The class I am trying to edit is a read only for some reason.
Jar files are compressed archives (zipped files) of .class files( and few other resources). .class files are compiled .java files. You can not edit a compiled file in normal situation unless you decompile to get source code, edit the code and recompile again.
Decompiling is a tedious process, thus getting a source code is the best option here.
Note: You can rename the .jar file to a .zip file and can open it using any compression tool such as winrar or winzip to see the content.
Is there any chance, to recreate a (netbeans-)project from a .jar file?
Becuase I trusted some silly cryption-software that corrupt's my file.
Is their any suggestion or solution?
I already extracted the .jar file with terminal commands 'jar xf MyJarFile.jar'.
But I can't read the code in it...
You could decompile the jar into the sources and then create a new project and drag all the sources into your src folder. I like using JD-GUI for decompiling .jars: http://java.decompiler.free.fr/?q=jdgui
I also recommend using JD-GUI, it helped me a lot when my simple text editor corrupted my .java files and I was able to convert the classes back into source using it.
delete the $ files first, then Jad is the best, jdgui makes errors.
Let's say I have a folder that contains various typs of files. Some of them are regular .java files that are to be compiled, others are in their own format and others are .java files that are not to be compiled (but I want them to appear in the /bin/ folder). Is it possible to accomplish that in Eclipse?
I've tried taking it out of the build path but them it won't appear in the output folder :(
The following screenshot depicts an example situation: I want Tests.java, X.java and Value.java to be compiled to the output folder bin/creates_java_contracts_file. In that same folder, I'll want to have rfn.rfn, Value.spc and X.spc, plus ValueContractsClass.java(uncompiled).
Another alternative is to either copy the files over to bin yourself, or change the file extension from .java to whatever you want (say, .njava or .foo).
I'm guessing you want to retain the .java files for some specific reason?
UPDATE
Exclude them from the build path, as you tried
Manually copy the .java files to your output folder
This prevents the files from being compiled, and they will survive a "Clean..." build, by my testing, meaning they don't get deleted when Eclipse scrubs the output folder.
If you are using ANT, you can do a simple file copy.
I have a jar file which is used in html file as applet. I want to modify the content of the jar file and to rebuild the jar file so that the html will work fine with the new jar file. How can i do this??
I already tried unzipping using 7zip nad modified the source and created the new jar. But when i use it in html it shows some java.lang.Classnotfound error
You can unjar or rejar the classes and source files as you wish.
unjar
jar -xvf abc.jar
jar
jar cf abc.jar input-files
http://docs.oracle.com/javase/tutorial/deployment/jar/build.html
Make the changes in the code (.java files), recompile to get the .class files. Then simply replace the old .class files in the jar with the new ones. I usually use WinZip, but you can use whatever app that can handle .Zip files. It should just work.
I've faced cases where the launcher of the app uses some sort of verification and checks for this kind of changes. I had to use a new launch script. This doesn't seem to be your case though.
This is surely possible from the command line. Use the u option for jar
From the Java Tutorials:
jar uf jar-file input-file(s)
"Any files already in the archive having the same pathname as a file being added will be overwritten."
See Updating a JAR File
A brief test shows this quickly updates changes apart from trying to delete the file.
I haven't seen this answer on other threads about modifying jar files, and many, marked as duplicates, suggest there is no alternative but to remake the jar completely. Please correct if wrong.
JARs are just ZIP files, use whatever utility you like and edit away!
Disclaimer: When reverse engineering any code be sure that you are staying within the limits of the law and adhering to the license of that code.
Follow the instructions above to unpack the JAR.
Find the original source of the JAR (perhaps its on SourceForge) and download the source, modify the source, and rebuild your own JAR.
You can also decompile the class files in the JAR. This is a rather advanced process and has a lot of "gotchas".