Code words implement the Forth kernel words. Code words are handy to collect actions inside a named word in the source text. This helps to clarify the source text.
All HolonJForth compiler words (e.g. : ; if ) are defined in the toolbox, in terms of meta compiler words of Holon. This enables you to look up the definition of every word in your program, even the definition of compiler words, which are usually hidden in the host. [I wonder whether someone wants to mingle with the compiler words, but you can if you feel like. Holon offers new degrees of programming freedom.]
HolonJ uses a proprietary objecttype mechanism in the compiler. Every Java variable (field) is represented by an objecttype in the host, which responds to the messages get, =: and others. The HolonJ objecttypes are defined in the toolbox module _Compiler.
The message get is optional. If you use a variable without a message, get is implied.