what is the difference of multiline and documentation?

Answer 1

Multi-line comments are collectively called implementation comments, while Javadoc comments are called documentation comments. Implementation comments are used for internal documentation. To internally document a program non-executable human-readable implementation comments are inserted. These comments should be used to give overviews of code and provide additional information that is not readily available in the code itself.

On the other hand Javadoc comments too inserted into the source code but they are read by a special javadoc tool in order to generate source code documentation.

Answer 2

Java multi-line or traditional comments (/*...*/)
Javadoc or Java documentation comments (/**...*/)

Answer 3

what if we run the program? will we find any difference ?