Eclipse auto-formatter, disable auto line-wrapping of comment lines

I think that the thing you are specifically asking about you can achieve by editing your formatter:

• Window -> Preferences -> Java -> Code Style -> Formatter. There edit you click on Edit...
• If you are using the default Eclipse formatter you will need to edit the profile name (you cna not edit built in profile).
• Go to comments
• Deselect line comment formatting.

That way no formatting of comments of the type // will be done.