How to Use Comments in Java
A comment in Java is a bit of text that provides explanations of your code. The compiler ignores comments, so you can place any text you want in a comment. Using plenty of comments in your programs is a good idea to explain what your program does and how it works.
Java has two basic types of comments: end-of-line comments, and traditional comments.
An end-of-line comment begins with the sequence // (a pair of consecutive slashes) and ends at the end of the line. You can place an end-of-line comment at the end of any line. Everything you type after the // is ignored by the compiler. For example:
total = total * discountPercent; // calculate the discounted total
If you want, you can also place end-of-line comments on separate lines, like this:
// calculate the discounted total total = total * discountPercent;
You can also place end-of-line comments in the middle of statements that span two or more lines. For example:
total = (total * discountPercent) // apply the discount first + salesTax; // then add the sales tax
A traditional comment begins with the sequence /*, ends with the sequence */, and can span multiple lines. Here’s an example:
/* HelloApp sample program. This program demonstrates the basic structure that all Java programs must follow. */
A traditional comment can begin and end anywhere on a line. If you want, you can even sandwich a comment between other Java programming elements, like this:
x = (y + /* a strange place for a comment */ 5) / z;