Creating a bucket on fake-gcs-server using the Java Storage client failed with: invalid character '\x1f' looking for beginning of value, raised from HttpStorageRpc.translate. Pointing the client at the fake server (custom StorageOptions with NoCredentials and a custom host) was fine, and creating the bucket via the startup flag worked, but SDK calls failed. Another user traced it: \x1f is the first byte of a gzipped payload. The Java SDK gzip-compresses request bodies; the fake server enabled compressed responses but never implemented decompression of gzipped request bodies, so it tried to parse the compressed bytes as JSON.