Editing View a Java Class File using a decompiler

{{TipImported
|id=54
|previous=53
|next=58
|created=March 22, 2001
|complexity=intermediate
|author=bhaskar_v_k
|version=5.7
|rating=148/48
|category1=Java
|category2=
}}
Do you wish you could view a Java Class File using Vim?

First of all you will need a Java Decompiler to decompile the Class File. I would suggest the JAD decompiler by Pavel Kouznetsov
* http://www.varaneckas.com/jad

It's a command line decompiler and absolutely free.

Next create a vimscript file called jad.vim:

<pre>
augr class
au!
au bufreadpost,filereadpost *.class %!d:jad.exe -noctor -ff -i -p %
au bufreadpost,filereadpost *.class set readonly
au bufreadpost,filereadpost *.class set ft=java
au bufreadpost,filereadpost *.class normal gg=G
au bufreadpost,filereadpost *.class set nomodified
augr END
</pre>

Note: Keep the Jad.exe in a directory without white spaces. The -p options directs JAD to send the output to standard output instead of a .jad file. Other options are described on the JAD site.

Next add the following line in the [[vimrc]] file.

<pre>
so jad.vim
</pre>

Next time you do vim abc.class, voila, you have the source code for abc.class.

NOTE: I have written the script so as to open the class file read only, So that u dont accidently modify it. U can also exted this script to unjar a jar file and then view each file in the JAR file.

==Comments==

I modified this a little bit to use the improved file runtime organisation of vim60, I don't know if other will like it better but here it is:
I added to filetype.vim:
 augroup filetypedetect
 au! BufRead,BufNewFile *.jad setfiletype java
 au! BufRead,BufNewFile *.class setfiletype class
 augroup END

and created in ftplugin a class.vim with
 %!jad.exe -noctor -ff -i -p %
 set readonly
 set ft=java
 normal gg=G
 set nomodified

----
If you don't want to 'hit ENTER' after every decompilation, you can add 'silent' to some of the lines:

 au bufreadpost,filereadpost *.class silent %!jad -noctor -ff -i -p %

and maybe even:

 au bufreadpost,filereadpost *.class silent normal gg=G

----
I can now select any class file, right click, and select the "Edit with Vim" option to view the source.

I'm just wondering, how do I change this to if I do the same to a jar file, and it will show me the contents of the jar file, as in a jar -tf, and if I select any of the entries, I can view the source?

I tried opening the jar file using WinZip, and if I view any of the entries in it using vim, I'll get something like this:
JavaClassFileReadException: can't open input file on `C:\Documents'
JavaClassFileReadException: can't open input file on `and'
JavaClassFileReadException: can't open input file on `Settings\gwunwai\Local'
JavaClassFileReadException: can't open input file on `Settings\Temp\Version.class'

I think that's because WinZip extracts the zip entries into my temp directory, which contains white spaces.

Is there some way around this?

----
you can change the command to %!jad.exe -noctor -ff -i -p "%"
(enclosed the % with quotes). It worked for me

----