Import: what's the faster?

Question

Hi,
my question is related to the "import" command. I'm quite sure that specifying each class with a single import line (i.e., without using wildcards such as '*') will produce a faster compilation, but someone told me that the use of wildcards will produce faster runtime programs. Is it true?
I don't think that the import can influence the runtime performances, but only the compiling ones. Nevertheless I'd like to know what do you think about, in order to discard my doubt.
Thanks.

Answer 1

>
I'll go even further:
If you have so many import statements in your source
code file that you feel it's necessary to use "import
package.*;", then that's a red flag that the source
file is too big. A refactoring may be in order.
To see if a source file is too big, I look at the "size" of the file. If you don't know how to do this, right click on the file and click properties, or go to the command prompt and type dir nameoffile. If you are using Linux, type ls instead of dir. I don't think the use of the * correlates well with oversized source files.
Here is the import statements for two classes in the JDK source files, "whose" programmers are most likely "smart people".
java.awt.Canvas:
import java.awt.image.BufferStrategy;
import java.awt.peer.CanvasPeer;
import javax.accessibility.*;
javax.swing.ComboBox:
import java.beans.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import javax.swing.event.*;
import javax.swing.plaf.*;
import javax.swing.border.*;
import javax.accessibility.*;
To be fair, I looked at many classes. The most explicit import statements I saw were about 6 (not 10), and 6 is closer to 3, so I win +). Joking. I did notice that files used from packages such as java.util and java.io were more likely to be explicity coded than those from the awt and swing packages.