Java organization of classes.

Java organization of classes

• It's normal to arrange java classes in packages to separate classes from each other given the type of data they handle.
• If you study Java API library you will see that all the classes are arranged inside the packages.
• A class is declared to belong to a particular package with the package statement.
• There can be only one package statement in a java file and the statement should be the first in the java file.
  Java Package notation example:

  package mytools.text;
  class TextComponent {
   ...
  }
  ...

• Package names are constructed hierarchically, using a dot-separated naming convention.

Java Importing Classes

package somewhere.else;
 class MyClass {
      mytools.text.TextEditor editBoy;
        ...
    }
...

package somewhere.else;
import mytools.text.TextEditor;
class MyClass {
    TextEditor editBoy;
    ...
}
...

package somewhere.else;
import mytools.text.*;
class MyClass {
    TextEditor editBoy;
    ...
}
...

import static java.lang.Math.*;
// This will import all static Methods from java.lang.Math class 
...
    // usage
    double circumference = 2 * PI * radius;
    double length = sin( theta ) * side;
    int bigger = max( a, b );
    int positive = abs( num );
...