package pkg1[．pkg2[．pkg3…]];

package net.java.util;

public class Something{

   ...

}

package animals;

interface Animal {

   public void eat();

   public void travel();

}

package animals;

/* 文件名 : MammalInt.java */

public class MammalInt implements Animal{

   public void eat(){

      System.out.println("Mammal eats");

   }

   public void travel(){

      System.out.println("Mammal travels");

   } 

   public int noOfLegs(){

      return 0;

   }

   public static void main(String args[]){

      MammalInt m = new MammalInt();

      m.eat();

      m.travel();

   }

}

import package1[.package2…].(classname|*);

package payroll;

public class Boss

{

   public void payEmployee(Employee e)

   {

      e.mailCheck();

   }

}

package vehicle;

public class Car {

   // 类实现

}

package com.runoob.test;

public class Runoob {

}

class Google {

}