Organizing Java files and other practicalities - JavaTech: An Introduction to Scientific and Technical Computing with Java - page 138

allows the source code to refer to Applet rather than java.applet.Applet .
That is, instead of
public class MyApplet extends java.applet.Applet {...}
we use
import java.applet.Applet;
public class MyApplet extends Applet {...}
Any appearance of the name Applet is automatically interpreted as java.
applet.Applet . There can be multiple import statements to import fully
qualified class names from multiple packages. All import statements appear at
the top of a class definition file, immediately after the package statement and
before the opening line of the class body itself. Of course, valid comments may
appear anywhere.
The java.applet package is small, containing only the Applet class. A
large package like java.io contains (in Java 1.4.2) 50 classes plus 16 exception
classes and 10 interfaces (see Chapter 9 for a description of I/O in Java). To use the
import notation for each of these classes could become unwieldy even though
a typical program would be highly unlikely to use more than just a few of the
50 classes. For example, a typical program might use the following classes from
the java.io package: BufferedWriter , FileInputStream , FileOut-
putStream , FileReader , FileWriter , etc. That program would also likely
check for at least java.io.IOException if not some of the sub-exceptions
like java.io.EOFException and java.io.FileNotFoundException .
In this case the list of imports at the top of the file would look like this:
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileOutoutStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.EOFException;
import java.io.FileNotFoundException;
...
public class MyClass {...}
Using classes from several other packages, as most non-trivial programs do,
would lead to a very long list of import statements. To reduce the size of the
list, the compiler also supports the * notation to import an entire package at once
rather than specifying each imported class name separately. Therefore, the above
example can be reduced to
import java.io.*;
...
public class MyClass { ... }