1. My company recently started using Open Message Queue (the Sun implementation of JMS) in its applications. Would we have to switch to ActiveMQ to use the Camel framework?
No, you can use the JMS component to connect to any JMS provider.
http://camel.apache.org/jms.html
Chapter 7 contains more information on how to use the JMS component (also a short intro to JMS is in chapter 2).
2. I was looking into Camel a few weeks ago, and downloaded the install file. It seemed (from the size of the download) to be a huge install. My first impression was that it would be heavyweight to run, sucking up lots of CPU cycles. Is this the case?
The core of Camel is only about 1.5MB. Other than that you only need a few more jars to run Camel. See
http://camel.apache.org/what-jars-do-i-need.html
The distribution size comes from all the components. You will not need to load all these components into memory unless you are connecting to all the 70+ types of things Camel can connect to. That is pretty unlikely
3. How steep is the learning curve for Camel?
We have found that users have an easy time learning Camel for the most part given its expressive and natural to read DSL (it almost reads as it does). That said, knowing something about
Java , Spring and also Apache
Maven would help you starting out a lot.
Cheers,
Jon