You can use a wide range of Java development environments, including the Java Development Kit (JDK) from Sun, to build Java CFX tags. You can download the JDK from Sun http://java.sun.com/j2se.
Macromedia recommends that you use one of the commercial Java IDEs, so you have an integrated environment for development, debugging, and project management.
To configure your development environment to build Java CFX tags, you must ensure that the supporting classes are visible to your Java compiler. These classes are located in the cfx.jar archive, located in one of the following directories:
Server configuration cf_root/wwwroot/WEB-INF/lib
J2EE configuration cf_webapp_root/WEB-INF/lib
Consult your Java development tool documentation to determine how to configure the compiler classpath for your particular environment.
The cfx.jar archive contains the classes in the com.allaire.cfx package, which are required for developing and deploying Java CFX tags.
When you create new Java CFX tags, you should compile them into the WEB-INF/classes directory. Doing this simplifies your development, debugging, and testing processes.
After you finish with development and testing, you can deploy your Java CFX tag anywhere on the classpath visible to ColdFusion. For more details on customizing the classpath, see Customizing and configuring Java.