View a Java Class File using a decompiler

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Tip: #54 - View a Java Class File using a decompiler

Created: March 22, 2001 18:21 Complexity: intermediate Author: bhaskar_v_k--AT--hotmail.com Version: 5.7 Karma: 148/48 Imported from: Tip#54

Do you wish you could view a Java Class File using Vim?

Well your query ends here.

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.geocities.com/SiliconValley/Bridge/8617/jad.html

Its a command line decompiler and absolutely free.

You can use any command line decompiler of ur choice.

Next create a vimscript file called jad.vim as

######################### FILE START ################ 
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 
######################## FILE END ##################### 

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.

so jad.vim 

Next time you do vim abc.class, viola, 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.

thanks

bhaskar

Any suggestions are welcome

Comments

Hi, first I love this script 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

b.cerrina--AT--wanadoo.fr , August 21, 2001 13:54

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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 

(thanks to myitcv on #vim--AT--EFnet)

roel--AT--SP-AM_almende.com , February 24, 2004 6:00

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Nice script!!

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?

gwunwai--AT--pacific.net.sg , June 6, 2004 23:06

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

Anonymous , July 13, 2005 11:18

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