C#：

class Base
{
  public void foo()
  {
     System.Console.WriteLine("base");
  }
}
 
class Derived : Base
{
  static void Main(string[] args)
  {
    Base b = new Base();
    b.foo();
    b = new Derived();
    b.foo();
  }
  public new void foo()
  {
    System.Console.WriteLine("derived");
  }
}

Java的：

class Base {
  public void foo() {
    System.out.println("Base");
  }  
}
 
class Derived extends Base {
  public void foo() {
    System.out.println("Derived");
  }
 
  public static void main(String []s) {
    Base b = new Base();
    b.foo();
    b = new Derived();
    b.foo();
  }
}

2)当从一种语言迁移到另一种语言时,我们需要确保顺利过渡.