I've been successfully using gzip compression with embedded tomcat 7. Example: Programatically enable GZIP Tomcat 7 (embedded).
After I ugraded to tomcat8, the responses started flowing in uncompressed.
Nor Tomcat8 configuration reference (https://tomcat.apache.org/tomcat-8.0-doc/config/http.html), neither Tomcat8 Migration guide (https://tomcat.apache.org/migration-8.html) mention this issue.
Any ideas?