Dynatrace automatically captures several thread related performance measures. Check out the list of measures and search for Thread. Also - click on "Create Measure" in that Measure Dialog in your System Profile and see what other measures are available - especially under Tomcat.
Last thing you can do is to capture ANY JMX MEtric from Tomcat. Check out https://community.dynatrace.com/community/display/...
I even had found the metrics, my question arose when the two metrics dynaTrace tomcat did not match the information obtained from the Tomcat Manager. Is there any reason to be different?
The answer my own question is that probably dynaTrace bring the sum of tomcat threads for all actors with a certain group of agents ... while I was viewing only one JVM. I will check the material, because I believe a JMX Custom is required.