Information
The STRICT_SERVLET_COMPLIANCE influences Tomcat's behavior in several subtle ways. See the References below for the complete list. It is recommended that STRICT_SERVLET_COMPLIANCE be set to true
When STRICT_SERVLET_COMPLIANCE is set to true Tomcat will always send an HTTP Content-type header when responding to requests. This is significant as the behavior of web browsers is inconsistent in the absence of the Content-type header. Some browsers will attempt to determine the appropriate content-type by sniffing
Solution
Start Tomcat with strict compliance enabled, add -Dorg.apache.catalina.STRICT_SERVLET_COMPLIANCE=true to your startup script.
Impact:
Changing this to true will change a number of other default values which is likely to break the majority of systems as some browsers are unable to correctly handle the cookie headers that result from a strict adherence to the specifications. Please refer to the referenced documentation for a complete list of changed values. Defaults, regardless of whether or not they have been changed by setting org.apache.catalina.STRICT_SERVLET_COMPLIANCE can always be overridden by explicitly setting the appropriate system property or element attribute.