TOMCAT 9 Modify Session ID Lenght

For tomcat 9 you can modify the length of Session ID or JSESSIONID value, for do this you should uncomment and add the next lines in the conf/context.xml file:

    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <Manager pathname="" >
        <SessionIdGenerator sessionIdLength="128" />
    </Manager>

In this example JSESSIONID is increased to 128

https://tomcat.apache.org/tomcat-9.0-doc/config/manager.html

I hope this helps you