help with java class's

[Chuma2]

i have a .jar file and id like to replace one of the files with a code i already have, is this possible if so can u plz help me -ill be home in like 7-8hrs and check all the responses
(btw the file i have isnt in binary its a code for the class

[DєfKOniK]

i have a .jar file and id like to replace one of the files with a code i already have, is this possible if so can u plz help me -ill be home in like 7-8hrs and check all the responses
(btw the file i have isnt in binary its a code for the class

reverse engineering... not familiar with it java wise. But can unjar the file and just decompile it. It wont give you the exact code to it, but if you can code it will do.