Symptoms

In some cases Support staff may give customers a patched class to add to their instance that will correct an issue or add extra debugging. After deploying this class and restarting, Confluence fails to start with the error message:

nested exception is java.lang.ClassFormatError: Incompatible magic value 3199925962 in class file com/atlassian/confluence/user/PersonalInformation

Cause

Certain browsers will corrupt class files when downloading them.

Resolution

• Ask Support to zip the class file first before uploading it
• Or, use another browser to download the file