What would be the easiest way to view classes, methods, properties, etc. inside a jar file? I'm looking for something equivalent to the very useful Lutz Roeder .NET Reflector - for Java
Using the JDK, jar -tf will list the files in the jar. javap will give you more details from a particular class file.
I usually open them with 7-Zip... It allows at least to see packages and classes and resources.
Should I need to see methods or fields, I would use Jad but of course, it is better to rely on (good) JavaDoc...
Now, somewhere on SO was mentioned some Eclipse plug-ins, to find in which jar file a class is located, perhaps they can do more (ie. what you requested).
[EDIT] Reference to SO thread. Not what is asked, but somehow related, thus useful: Java: How do I know which jar file to use given a class name?
What I use personally is JD-GUI. It is a free 'decompiler', as it allows you to see the source code, classes, and objects in the classes, as well as see the file structure in a tree menu to the left. However, it does not allow you to modify the classes directly.
JD-GUI's website: http://jd.benow.ca/
Method names, fields, etc.
By adding a jar to a project in an IDE, you can usually see methods and field names, but not the detailed implementation. NetBeans can do it, Eclipse probably, IntelliJ probably, etc. You can browse the jar structure directly within the IDE.
Just the contents
For anything such as viewing the contents, you could use :
jar tvf jarfile.jar- winzip or any zip tool
The source code
To access source code, you would use a decompiler such as JAD or one of its frontends or another decompiler. If the code is obfuscated, then ...
Extending Tom Hawtin answer, you can pipe the listing to filter out desired class or files:
jar tf my-fat-jar-file.jar | grep filename
This should work on bash/zsh and similars, or emacs' eshell.
Additional information: https://docs.oracle.com/javase/tutorial/deployment/jar/view.html
Use unzip -l <jar-file-name>.jar for example, if you have a jar file with name test.jar then unzip -l test.jar will list the content of jar file.
According to the manual of unzip command with option - l.
list archive files (short format). The names, uncompressed file sizes and modification dates and times of the specified files are printed, along with totals for all files specified. If UnZip was compiled with OS2_EAS defined, the -l option also lists columns for the sizes of stored OS/2 extended attributes (EAs) and OS/2 access control lists (ACLs). In addition, the zipfile comment and individual file comments (if any) are displayed. If a file was archived from a single-case file system (for example, the old MS-DOS FAT file system) and the -L option was given, the filename is converted to lowercase and is prefixed with a caret (^)
You can also use zipinfo <your jar file>. if your OS supports this.
Use WinRar. It will open the folder structure for you in intact manner. Also allows in-archive editing, while preserving paths.
Afterall, a JAR file is a ZIP archive only.
If you like to see whats inside, simply rename as first option below..
F2 & Rename to jarfile.zip//Use any unzipper...jar tvf jarfile.jarjar tf jarfile.jar
If I understand correctly, you want to see not only classes but also methods, properties and so on. The only tool I know that can do it is Eclipse - if you add a jar to project classpath, you would be able to browse its classes with methods and properties using usual package explorer.
Anyway, this is a good idea for a good standalone Java tool
Jad is klunky and no longer maintained. I've switched to "Java Decompiler", which has a slick UI and support for new language features.
Every decompiler I've used, though, runs into code it doesn't successfully decompile. For those, it helps to understand the disassembled Java byte code produced by the standard JDK tool, javap.
Well, a jar-file is just a zip-file, so if you unzip it (with your favorite unzipping utility), you get all the files inside.
If you want to look inside the class files to see the methods, you'll need a tool for that. As PhiLho mentions, Eclipse is able to do that (by default), and I would think most Java IDEs are capable of that.
In Eclipse 3.4 do
- Drag the jar file in question into a Java project. A copy of the jar file appears.
- Right click on the jar file, and choose "Build Path" -> "Add to Build Path".
- Jar file is moved to "Referenced Libraries" node, where it can be opened and navigated in the Project Explorer pane.
If seeing source code too is an issue, open a new question.
For navigation on Jar-file level (as a zip file) I use 7zip which works very well, and allows seeing and editing entries which is great for trouble shooting.
One way to do this is to open the perspective in "Package explorer". Doing this you can see the structure of your jar with class details. For this check the library folder in your project using package explorer.
Window>>Show View>>Other>>Java>>Package Explorer
Another way is, you can use JarPlug as a eclipse plugin. This works in eclipse/springsource
If you are in windows and using powershell and you are looking for a file in a jar you can do:
jar -tf .\[JAR_NAME] | where {$_ -match "[FILENAME]"}
jar -tvf file_name.jar
above will only print names of the files.
To view the content of files, you can extract the files in a folder by:
jar -xvf file_name.jar
this will unzip jar file & put the content in same directory where you are running this.
Or in Windows rename .jar file to .zip & then you can unzip to extract & view the content of jar file. As jar is internally a zip file.
You can open them with most decompression utilities these days, then just get something like DJ Java Decompiler if you want to view the source.
Bndtools provides a free JAR viewer plugin for Eclipse.
Add the Eclipse update site and install only the viewer.
I prefer JAR Browser, it has a simple interface where you can browse multiple JARs, and search for a specific class across multiple JARs simultaneously.
Eclipse 3.4 JDT
It is not the quickest way because you have to drag it into your eclipse first. But you will have full java class browsing, even with decompile enabled.
I've set the default action in windows to "Open with WinZip". This makes it easy to manage JARs as archives. You can even add/remove files manually.
I think Java Decomplier is your best option you can download from here: http://jd.benow.ca/ Preview http://jd.benow.ca/img/screenshot17.png
My requirement was to view the content of a file (like a property file) inside the jar, without actually extracting the jar. If anyone reached this thread just like me, try this command -
unzip -p myjar.jar myfile.txt
This worked well for me!
You could try JarSpy. There is an IDEA plugin version of it that I use.
Your IDE should also support this. My IDE (SlickeEdit) calls it a "tag library." Simply add a tag library for the jar file, and you should be able to browse the classes and methods in a hierarchical manner.
On Mac there's Jarzilla
I use JarExplorer or JarVisualizer.
You could try JarNavigator to view and search contents of a jar file.
java -xf some-j.jar will unzip a JAR file.
Also you can use Luyten - An Open Source Java Decompiler Gui
来源：https://stackoverflow.com/questions/320510/viewing-contents-of-a-jar-file