How many Threads used in an ESB Service?

Issue

We have an end-to-end invocation as below:
WS Client -> JAX-WS service -> ESB service -> Business service

• The initial esb call is made from JAX-WS is using synchronous service invoker.
• We are using staticwiretap[asynchronous] to make internal service calls as mentioned

We would like to know if
1. This entire invocation is serviced on a single thread or more than one thread.
2. If it requires more than one thread, could you please tell us how many threads would be required for the attached jboss-esb.xml.
3. Currently, we have configured maxThreads property to 100 assuming that each transaction will use only one thread.
<property name="maxThreads" value="100"/>

• Is there a way to check how many threads are idle/used at any point in time.