Import confusion

Question

import java.io.*
and
import java.io.BufferedReader ;
import java.io.InputStreamReader ;
import java.io.IOException ;
are same or different ?
io.* means all classes are included ?

Answer 1

praggy wrote:
you mean to say that any time rather than writing specific
java.io.DataInputStream;
if if write java.io.*; it is much safe.I just meant that "import java.io.*;" would have more or less the same effect as writing an import for each of the classes in the java.io package.
There are a couple of problems with using the "*" form. (By the way it is called type import on demand)
(1) It is quite possible for classes in two packages to have the same name. (Think about the Date class for instance.) If you say
import java.sql.*;
import java.util.*;
    // later...
Date d = ...Which Date do you mean? You would have to consult the "rules" to find out. A single type import is much clearer.
(2) The type import on demand is less self documenting. If you include a single type import for each class you need (and none you don't need) then you can tell at a glance what the dependencies are.
I don't consider it a problem that (as was suggested earlier) "Through java.io.* you only get the classes and interfaces in java.io package but not other package inside java.io package." Because you shouldn't expect this in the first place. The type import on demand is just that: a type import, not an import of subpackages. Ie, just an import of classes and interfaces.