End of line comments:

// comment

Convenient but if you write code after the //, it all gets grayed out.

Block comments:

/* comment */

Advantage is that they can appear anywhere, span multiple lines, etc.

And here’s a line of code with a comment in the middle of it:

int counter /* comment */ = 0; Please don’t do that. It’s legal, but it’s poor coding practice, because it makes the code harder to read. – Java 7 for Absolute Beginners

Note that Javadoc comments are similar to block comments but with an extra asterisk at the beginning:

/** * This method makes a Cat object chase the given Mouse object. * @param mouse an instance of the Mouse class for our cat to chase */’ – Java 7 for Absolute Beginners

Really important tip: Don’t worry about line breaks when you’re writing comments. Press Command + Shift + F and it formats everything. You want to keep comments to about 80px. Get into the issue of line breaks with code. Sometimes line breaks with commands can be problematic – such as wrapping comment code.


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