Java：注释/* * * */

Question

Quick question, it there a difference between:

/* This is first line of comments
This is the second line
And this will be the last line
*/

and:

 /*This is first line of comments
*This is the second line
*And this will be the last line 
*/

in java language?

The source I learned from teaches the second form, but I found out the fist one works too.

Answer 1

There is no difference at all as far as the compiler is concerned. It's just a matter of what looks pretty and what documentation generators rely upon. That last point is surprisingly important: particularly in Java. (Javadoc relies upon well-defined comment forms.) /* defines the start of a comment, and you'll stay in "comment mode" until the first */ is reached.

So further /* are allowed within a comment block (but they don't nest so you still only need one closing */ ). And the single line comment // within a comment block is benign: //*/ will close a comment block.

Answer 2

There is difference between

/* This is first line of comments
This is the second line
And this will be the last line
*/

And

/**
 * This is javadoc
 * Refer to <a href="http://docs.oracle.com/javase/7/docs/technotes/guides/javadoc/">javadoc</a> for details
 */

Answer 3

/* text.... */

The compiler ignores everything from /* to */.

/** documentation */

This is a documentation comment and in general its called doc comment.
The JDK javadoc tool uses doc comments when preparing automatically generated documentation.