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 \"// com

Answer 1

It makes modifying and formatting long comments extremely painful.

Most editors provide some sort of wrapping facility to automatically wrap text into lines of readable length. If every line starts with a '//' those will get moved around, then have to be deleted, and new ones re-inserted. All that tedious work can be avoided using '/* */ style comments.