I am trying to write a program in Java, which would collect a specified set of files from the physical location and place them in a jar in a certain directory.
I know I can use java.util.jar package for this. The package is great for sure, but I was wondering if there are any third party libraries that anyone at SO has used which they could recommend.
TL;DR: pick up files, create jar by placing them in pre-defined directories, all at run time in a java file.
P.S: I did not find any similar references to this question, but if there are then please refer me. Also, the title might be misleading, but I didn't find better words to explain my problem.
EDIT 1: I am not in anyway saying java.util.jar is bad or incomplete. All I am asking is if anyone has used any alternative solutions!
EDIT 2: I am trying to create the jar from inside the java program. The jar can be pretty big (~500mb) too. Trying to jar media files as well. So simply put, I pick up various files from certain locations on my drive and try to create a jar file by placing them in standard locations.
Thanks,
Ivar
Look at the java.util.zip package. Jars are just zip files with some extra stuff in 'em
Related
it's been a while since i've been working with java and especially with eclipse. My professor sent me a huge folder with many subfolders and subsubfolders, that mainly contain .class java files. Now I'm supposed to work on these files, but i just can't seem to figure out how to get all of them working. I found a few solutions for single class files, but i have a whole folder hirarchy here that i want to work on.
I hope you can help me - I read something about decompiling? How does that work?
Note that I have around 50 different files here that need to be accessible.
Thank you very much!
I suppose the class you are attending is not something like "CS 902 - Reverse Engineering", because if that was the case, you would know what to do with the .class files.
So, one of the following holds true:
Your professor has made a mistake, and instead of sending you the java files, he/she sent you the class files instead.
Your professor sent you the entire project, which contains both .java and .class files, and for some reason you have only managed to find the .class files, while the .java files are there, and you just haven't found them. Unfortunately, the convention in the java world is to store .class files in a subfolder under the project root, so if you copy the project folder, you are copying .class files together with everything else.
Your assignment is to write new code which makes use of classes and interfaces supplied by your professor, but your professor does not want you to have the source code of those files. In this case, you can still work with the .class files, because the public definitions contained therein are parseable by Eclipse and usable in your project, without any reverse engineering. So, what you need to do is to find a way to tell eclipse that these .class files form a "Class Library" which is supposed to be used by your project, and then go ahead and develop new .java files making use of the library. I don't remember how this is done in Eclipse, but you should be able to find it out by yourself, or look it up, or perhaps someone else might post a how-to answer. However, at this point we do not even know whether this is in fact what you need to do.
You can use a java decompiler like JD-GUI, you can find it at http://jd.benow.ca/ . This is a very handy tool to have when you want to view a decompiled version of your jar. There are plugins available for eclipse and intellij as well.
I have a program that imports its required classes from a .jar source.
However I have also unzipped said .jar source in order to search its file directory to gather up class names for a list within the same program.
The problem is that the class ** appears more than once in the classpath, this is due to it being simultaneously in the bin and as a library. I need both elements for separate, yet equally code features.
I've found removing the file directory of the .jar source solves the problem however my list is now blank.
Anyone know of a way to do both?
Based on what you said above in the comments, if your package names start with com.somethingfromsourceforge.* then I would change com.somethingfromsourceforge to com.hopeless and the pathing issue should be resolved. Try this and let us know.
I have created a program in Java using eclipse that contains a couple of folders with graphics and files that get read from and written to. What I need is a way to export the whole program in some executable format so that anyone can run my program.
I've had a look around online and I notice that people suggest creating an executable JAR file. However I have my reservations about this since I suspect it will choose to ignore the graphics & other files that the program uses, only focusing on the actual source code.
Please could someone suggest a solution to this issue, it is absolutely essential that the files and graphics are packaged up with the rest of the code.
On another related note; at present I'm referencing the files & graphics using files paths that are specific to my computer. If I were to use another solution such as creating an installable program how should I handle these filepaths? Apologies if this is a naive question, however I'm new to this sort of thing.
However I have my reservations about this since I suspect it will choose to ignore the graphics & other files that the program uses, only focusing on the actual source code.
When you think you may have a solution but it doesn't work, you should test that theory.
A jar file is absolutely the right solution for this. However, you need to make sure that Eclipse considers them as resources on the build path so that it will copy them into the jar file. Then you just need to refer to them from the jar file:
On another related note; at present I'm referencing the files & graphics using files paths that are specific to my computer. If I were to use another solution such as creating an installable program how should I handle these filepaths?
Use Class.getResource() or Class.getResourceAsStream() or the ClassLoader equivalents. That will let you load your resources directly from the jar file, without even having separate files on the file system.
I'm working on a java android project. this project requires to use specific commands.
these commands are all developed in c++/c but I've been given two files (.jar and .so) that are supposed to "turn them into" java, so I can use them in my java android project.
The thing is, what am I supposed to do with these 2 files?? I've read a lot of stuff (mostly about creating the .jar and .so, but I don't care about this step, for I already have the 2 files)
I tried to import the .jar (import external lib), I tried to add the .so via the static loading :
//static {
// System.loadLibrary("MySoFile");
// }
All I get is a stack overflow error or a problem with the DEX file...
Has anybody ever tried to do this??
I don't seem to get the point here...all I want to do is being able to use the commands in the .jar file.... ://
thanks in advance!!
Take a look at this answer about adding jar files. '.so' files can usually just be drag and dropped to the project.
All you need to do is make sure the jar is in your classpath and you can then access the classes within this jar. A jar is just an archive of classes, you don't need to load the library into memory or something similar.
You may want to read the answer to the question here How to use classes from .jar files?
we have downloaded jar files for lambdaj and its dependencies which are again jar files.
we do not know how to go about it. we have copied these files in the
C:\Program Files\Java\jre6\lib\ext
have set the class path in environment variales as:
variable: classpath
path: C:\Program Files\Java\jre6\lib\ext
but we do not know how to go further. we want to run some lambdaj programs.
can anyone suggest how to run lambdaj programs?
You would run a Java program that requires lambdaj in exactly the same way you'd run any other java program with an external dependency, i.e. by invoking the java executable passing in the fully-qualified name of the Main class, or the JAR with an appropriate manifest, or by deploying it in a servlet container, etc. Additionally you should be putting the LambdaJ JAR on the classpath for this invocation, not in the lib folder for your entire JVM.
What have you tried so far and why/how is it not working? Your question at the moment is a bit analogous to "I want to use Microsoft Word to view some Word documents, how do I do this?".
Update for comment 1: You said "it's not working". That doesn't help anyone address your problem as it gives no clue what you expected to happen and what you observed, only that they were different. As for where JAR files can be stored - you can put them in any directory, so long as that directory is on the classpath (or you add it to the classpath) of the Java application that runs. The canonical place to put external dependencies is in a folder called lib below the root of your project, but the important thing is that you choose somewhere consistent and sensible.
It sounds like you don't quite grok Java and classpaths yet. If you have followed some tutorials and are still stuck, ask for help to let you understand. Adding more detail to your question, including the layout of your files, the commands you issued, and the response that came back would be useful too.
If you are using Netbeans create a project and right click on the Libraries folder within the desired project. Click Add JAR/Folder...