How to add description to method or class

You can use javadocs using /** comments */

For a method basically you can have

/**
The Desciption of the method to explain what the method does
@param the parameters used by the method
@return the value returned by the method
@throws what kind of exception does this method throw
*/

You can use this link for futher help http://www.oracle.com/technetwork/java/javase/documentation/index-137868.html#descriptions

Use javadoc comments - /** This is a comment */

Check this link for detailed documentation http://en.wikipedia.org/wiki/Javadoc