| Error Message | Likely Cause | Solution | |----------------|----------------|-----------| | Exception in thread "main" java.lang.UnsupportedClassVersionError | Java version mismatch | Install Java 11 or 17 (the version compiled against) | | Could not find or load main class | Corrupted JAR or missing manifest | Redownload the file or verify it wasn’t truncated | | Connection refused | The target server is offline or wrong IP | Check network, firewall rules, and server status | | No such file or directory | You mistyped the filename | Ensure the exact case: ravenbsclient189jar (all lowercase) |
| Your situation | Action | |----------------|--------| | You don’t know the source | Delete it | | You downloaded from a suspicious link | Delete + scan PC | | It’s from a trusted private server community | Run in VM first | | You just want to see what it does | Use Windows Sandbox | file name ravenbsclient189jar