I have a problem and I do not seem to find anything on the web regarding it: I have created an application in Java that creates zip files using java.util.zip. The application was originally developed using JDK 1.5 on a 32-bit Machine and it worked flawlessly. Now the application needs to run on a 64-bit machine (Java's motto: write once run everywhere). The JDK on that machine is the 64-bit version and the application generates the zip files but the problem is that the files can no longer be opened. WinZip/Windows indicate that the file is corrupt (the "corrupt" file has the same size as the file generated on a 32-bit machine). Has anyone encountered the same problem or similar?