It's addressed near the end: > Eliminating the main method altogether may seem like the natural next step, but it would work against the goal of gracefully evo

It's addressed near the end: > Eliminating the main method altogether may seem like the natural next step, but it would work against the goal of gracefully evolving a first Java program to a larger one and would impose some non-obvious restrictions (see below): The "see below" boils down to there being a number of differences between how class-level and method-level code units (fields vs. variables) work, and blurring the line there isn't worth the minor additional effort of writing a main() method.