How to Javadoc a Class's Individual Enums

You do it just like any other variable you would javadoc.

/**
 *  Colors that can be used
 */
public enum Color
{
    /**
     * Red color
     */
    red,

    /**
     * Blue color
     */
    blue

}

EDIT:

From Paŭlo Ebermann : The enum is a separate class. You can't include its full documentation in the enclosing class (at least, without patching the standard doclet).

You can create link to each enum's item. All items will be listed in javadocs to enum class.

/**
 *  Colors that can be used
 *  {@link #RED}
 *  {@link #BLUE}
 */
public enum Color {

    /**
     * Red color
     */
     RED,

    /**
     * Blue color
     */
    BLUE
}