Let’s say you have deployed your package and then suddenly you realize that your code need some changes. Now you can save some work (and time); by just updating the single class file.
(Make sure you have build your new .java code file. – Check the time stamp of the class file (it’s in the WEB-INF/classes/ folder, if it’s changed.)

1. Since .EAR files are archives you can open the .EAR file with WinRAR.
2. Browse to the to updated Web Archive (for example projectWeb.war) in WinRAR
3. Open the war file with WinRar. (make sure it won’t be opened by WinZip); right click the .WAR file and choose View File (ALT+V)
4. Now the .WAR file is opened in WinRar simply drag the updated .class file into the archive.
5a. WinRar will notice that the .war file has been updated. – Say yes to the popup.
5b. WinRar will notice that the .ear file has been updated.- Say yes to the popup.
6. Double check, close WinRar, open the .ear file again, and check if the .war file as well the .class file where updated (see timestamp).