How is Java source file organized

Java Source File

All Java source files must end with the .java extension. A source file should contain, at most, one top-level public class definition. If a public class is present, the class name should match the unextended filename.

Three top-level elements known as compilation units may appear in a file. None of these elements is required.

If they are present, then they must appear in the following order:

1. Package declaration
2. Import statements
3. Class, interface, and enum definitions

Example

package MyPack;//from w w  w . j a va2  s. co  m
import java.util.Date;

public class Main {
  public static void main(String args[]) {
    System.out.println(new Date());
  }
}