From beginning on CaptainCasa provided a sophisticated hot deployment mechanism that is a significant accelerator during development: after changing your Java code you do not have to rebuild and restart your runtime (Tomcat, …) but classes are exchanged within the runtime “on the fly”. – CaptainCasa’s hot deployment itself is built on running the UI-related classes in some own class loader and restarting this class loader independent from the class loader of e.g. your Tomcat runtime.
Now there is interesting alternative which is especially interesting for projects which do not strictly separate the UI-related classes from the logic-related classes: the open source technology HotSwapAgent allows to exchange/update the classes that are loaded within your running Tomcat (or other runtime) dynamically. The installation and configuration is simple, we use the technology both internally and in customer projects in the meantime.
Please check the following documentation for details: Developing with HotSwapAgent
(This documentation is part of our official documentation site as well – section “Specific Documentation”.)