Velocity is a view technology comparable to JSP) that Turbine officially supports. Many Turbine developers feel Velocity is an excellent alternative to JSP for web application development.
Jetspeed 1 is an open source portal engine built on top of the Turbine web application framework. It was used to develop a ready-to-go portal solution with open technology.
Turbine uses Log4j2 for a logging framework. No more commenting System.out.println()'s in your code!
Maven is a Java project management and project comprehension tool. Maven is based on the concept of a project object model (POM) in that all the artifacts produced by Maven are a result of consulting a well defined model for your project.
Torque is a persistence layer. Torque includes a generator to generate all the database resources required by your application and includes a runtime environment to run the generated classes.
Maven article - Maven ties together tools for better code management. by Jeff Linwood, published in JavaWorld on October 11, 2002.
Velocity Introduction - Start up the Velocity Template Engine. by Geir Magnusson, Jr., published in JavaWorld on December 28, 2001.
On the Velocity site, there is Jon Stevens' You Make The Decision, which compares Velocity to JSP.
Then there is Jason Hunter's Problems with JSP.