HTTP header size limit

There's no HTTP header size limit

but Tomcat has HTTP header size limit.

In Tomcat 7, it's 8KB

and you can set 'maxHttpHeaderSize' to change it:

The maximum size of the request and response HTTP header, specified in bytes. If not specified, this attribute is set to 8192 (8 KB).

You can find a sample for testing Tomcat HTTP header size limit as follows:

https://github.com/izeye/samples-spring-boot/blob/master/src/test/java/samples/springboot/gs/serving_web_content/TestControllerTests.java

References:
http://stackoverflow.com/questions/686217/maximum-on-http-header-values
http://tomcat.apache.org/tomcat-7.0-doc/config/http.html