To create a java package

The package statement (for example, package graphics;) must be the first line in the source file. There can be only one package statement in each source file, and it applies to all types in the file.

Note: If you put multiple types in a single source file, only one can be public, and it must have the same name as the source file. For example, you can define public class Circle in the file Circle.java, define public interface Draggable in the file Draggable.java, define public enum Day in the file Day.java, and so forth.

You can include non-public types in the same file as a public type (this is strongly discouraged, unless the non-public types are small and closely related to the public type), but only the public type will be accessible from outside of the package. All the top-level, non-public types will be package private.

If you put the graphics interface and classes listed in the preceding section in a package called graphics, you would need six source files, like this:

//in the Draggable.java file

package graphics;

public interface Draggable {

    . . .

}

//in the Graphic.java file

package graphics;

public abstract class Graphic {

    . . .

}

//in the Circle.java file

package graphics;

public class Circle extends Graphic

    implements Draggable {

    . . .

}

//in the Rectangle.java file

package graphics;

public class Rectangle extends Graphic

    implements Draggable {

    . . .

}

//in the Point.java file

package graphics;

public class Point extends Graphic

    implements Draggable {

    . . .

}

//in the Line.java file

package graphics;

public class Line extends Graphic

    implements Draggable {

    . . .

}

If you do not use a package statement, your type ends up in an unnamed package. Generally speaking, an unnamed package is only for small or temporary applications or when you are just beginning the development process. Otherwise, classes and interfaces