Source Files

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

package MyPack;
import java.util.Date;

public class Main {
  public static void main(String args[]) {
    System.out.println(new Date());
  }
}
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Package:
  1. What is a Java Package
  2. Importing Packages
  3. static import
  4. Source Files