Tomcat blocking when handle huge HTTPS connections

Tomcat blocking when handle huge HTTPS connections

We use HTTPS to do file upload from client to tomcat web server, sometimes
we will met the tomcat blocking issue, but don't know why this happens, in
normal case, file can be uploaded successfully.
When tomcat is blocking, all the https connections can't be created, after
about 5 minutes, some https connections will be released.
Not sure what trigger the tomcat go blocking, and how to avoid this,
helps!!!Thanks!