Verify the source, run a malware scan, and open it only in a secure, isolated environment (like an IDE or a virtual machine). To give you a more specific review, could you tell me:
This is a RAR archive, which means it likely contains multiple related files, such as Java classes (implied by the .Clazz naming convention), source code, or project configuration files.
Like any compressed file from an untrusted source, it should be scanned with antivirus software before extraction. The contents, particularly if they are compiled Java ( .class ) files, should be analyzed to ensure they perform the expected tasks.
Drainage Somerset