As you become more advanced at writing Java programs, the solutions you use to create your programs will become longer and more complicated. Furthermore, as we will see in later chapters, Java was designed to manage complexity by having us divide up our code into separate classes, very often across multiple files.
Code comments are a part of the Java program that do not have any function in the program itself. The compiler ignores them. They serve to help the programmer document, explain, and clarify their code to make it more understandable to themselves at a later date, or to other programmers who might need to use or modify it.
We have already seen a single-line comment:
// this is a comment explaining what is going on
The previous comment begins with the two forward slash characters //. The comment ends at the end of the line. So, anything on that line is for humans only, whereas anything on the next line (unless it's another comment) needs to be syntactically correct...