public class A{ 
  private ArrayList components = new ArrayList(); 

  public void add(B component){ 
    this.components.add(component); 
  }

   public void remove(B component){
     this.components.remove(component);
   }

   public int getComponentsCount(){
     return components.size(); 
  }

}

Ok, one of my friend comes in and has another idea of how to implement this:

public class A{ 
  private ArrayList components = new ArrayList(); 

  public BCollection getComponents(){ 
    return new BCollection(components);
   }
}


and Here is his BCollection class:


public class BCollection{ 
  private ArrayList components = null; 
  
  public BCollection(ArrayList components){ 
    this.components = components; 
  }

  public void add(B component){ 
    this.components.add(component); 
  }

  public void remove(B component){
     this.components.remove(component);
  } 
  
  public int getComponentsCount(){ 
    return this.components.size(); 
  }

}


According to him, that way we don't to have "A" around to operate on components. But to me, it's kind of breaking the encapsulation, which shoudl be avoided. 

What do you guys think? Any strong reason why/why not doing this?

Thanks,
Bujin Wang