Why is '//' style multiline comment bad (in Java)?

Question

http://java.sun.com/docs/codeconv/html/CodeConventions.doc4.html#286 I was reading the above section of Java coding convention and started to wonder why it says "// comment.....shouldn't be used on consecutive multiple lines for text comments" Copy pasted the relevant section here for convenience: The // comment delimiter can comment out a complete line or only a partial line. It shouldn't be used on consecutive multiple lines for text comments; however, it can be used in consecutive multiple lines for commenting out sections of code. Is there any rational reason for this?

Accepted Answer

Actually, I've been using `//` for multiple lines for years and never suffered any serious problem with it. I'm not a big fan of `/*...*/` anymore because you get:

```
/* I'm commenting out all this code for a moment
  ...
  /* And here is a multi line comment
     that was hidden in the middle */
  ...
*/ 
```

Thank the compiler it gets upset and tells me of the problem.

Where as:

```
...
// And here is a multi line comment
// that was hidden in the middle
...
```

becomes with a single macro:

```
// ...
// // And here is a multi line comment
// // that was hidden in the middle
// ...
```

and is happily reversed with another single macro that returns it back to the original form

and as for:

```
  // but now you have 
  // trouble edditing
  // your comments so
  // that every  line
  // is of equal size
```

I say:

```
  // Tough, this is a piece of code not a 
  // published novel
  // and if varying lengths
  // make
  // it hard for you to read then heaven
  // forbid how you handle the code
```

And don't you just hate edditing:

```
/******************************************************************
 * Program: Foo.java                                              *
 ******************************************************************
 * Author:  Codey Art Work                                        *
 * Purpose: To do something with something and get something not  *
 *          forgetting something else.                            *
 ******************************************************************
 * Revision History:                                              *
 ******************************************************************
 *  Date  | Author |                                              *
 *--------|--------|----------------------------------------------*
 * 1/2/09 | Jack   | Now I have to keep all my comments in this   * 
 *        |        | tiny little space and if I edit it I just go *
 *        |        | aaarrrrrrggggggggggghhhhhhhhhhh!!!!!!!!!!!!! *
 ******************************************************************/
```

which always seem to appear in places insisting on `/* */` over `//`

And I'd just like to say to the Stack Overflow guys, this is really cool editor. Doing code samples is so easy.

Why is '//' style multiline comment bad (in Java)?

Solution

Problem